But the dozing might just be a proxy for sleep apnea.
Regular daytime dozing forewarns of a significantly increased risk of stroke in older Americans, researchers reported at the American Stroke Association’s International Stroke Conference 2008.
Stroke risk was two- to four-fold greater in those with moderate dozing. This suggests that daytime dozing “may be an important and novel stroke risk factor,” said Bernadette Boden-Albala, Ph.D., lead author of the study.
In this study, dozing refers to a person unintentionally falling asleep.
Among 2,153 participants in a prospective study with an average follow-up of 2.3 years, the risk of stroke was 2.6 times greater for those classified as doing “some dozing” compared to those with “no dozing.” Those in the “significant dozing” group had a 4.5 times higher risk.
“Those are significant numbers,” said Boden-Albala, an assistant professor of neurology at Columbia University’s College of Physicians and Surgeons in New York City. “We were surprised that the impact was that high for such a short period of time.”
Sleep scientists previously have found evidence that people who experience apnea, brief periods when breathing stops during sleep, have an increased stroke risk. Research indicates that daytime sleepiness can result from sleeping poorly because of nighttime apnea.
Maybe the sleep apnea causes a sleep deficit which causes cardiovascular damage. Or maybe an oxygen deficit all night long while repeatedly going into shallow breathing modes causes the damage.
Sleep apnea is linked to all sorts of diseases you want to avoid like heart disease and cognitve decline. Of the various risk factors for sleep apnea about the only one you can do something about is obesity (unless you want to get a sex change operation into being a female).
Getting a stroke is up there with brain cancer and Alzheimer's Disease on the list of Terrible Things That Happen To Our Brains In Old Age. Together they provide a very compelling reason why we should support more rapid development of rejuvenation treatments to reverse the aging process.
You shouldn't complain to fat people about their weight. They are saving you money. A study in Plos Medicine found that obesity costs more in the short term but earlier death cuts total medical costs.
Background
Obesity is a major cause of morbidity and mortality and is associated with high medical expenditures. It has been suggested that obesity prevention could result in cost savings. The objective of this study was to estimate the annual and lifetime medical costs attributable to obesity, to compare those to similar costs attributable to smoking, and to discuss the implications for prevention.
Methods and Findings
With a simulation model, lifetime health-care costs were estimated for a cohort of obese people aged 20 y at baseline. To assess the impact of obesity, comparisons were made with similar cohorts of smokers and “healthy-living” persons (defined as nonsmokers with a body mass index between 18.5 and 25). Except for relative risk values, all input parameters of the simulation model were based on data from The Netherlands. In sensitivity analyses the effects of epidemiologic parameters and cost definitions were assessed. Until age 56 y, annual health expenditure was highest for obese people. At older ages, smokers incurred higher costs. Because of differences in life expectancy, however, lifetime health expenditure was highest among healthy-living people and lowest for smokers. Obese individuals held an intermediate position. Alternative values of epidemiologic parameters and cost definitions did not alter these conclusions.
Conclusions
Although effective obesity prevention leads to a decrease in costs of obesity-related diseases, this decrease is offset by cost increases due to diseases unrelated to obesity in life-years gained. Obesity prevention may be an important and cost-effective way of improving public health, but it is not a cure for increasing health expenditures.
However, if you expect the development of artificial intelligence and/or nanobots to make manufacturing cheaper in a few decades then it makes sense to get everyone to eat less and stop smoking now. Any deferral of medical costs, even if they'll be greater in the future, will be easy to afford once the Singularity happens.
Of course, if the nanobots take over and turn hostile toward us in the Singularity (and FuturePundit does not wear Panglossian glasses) then we won't get treated for illnesses and we won't become young again. Just as the technology comes into existence that can make our bodies young again the artificial intelligences in control of that technology might just make us extinct.
Update: This study ignores one important consideration: productivity A healthier person produces more wealth. One needs to look at lifetime income earned and taxes paid along side of health care costs to come up with net economic effects. I'm expecting non-smokers to produce more than smokers because the brains of non-smokers operate less toxified. Non-smokers are going to miss fewer days of work due to illness and operate more productively while they are there. I watch the smokers taking smoking breaks. What does that cost?
People in their 40s are most unhappy?
Using data on 2 million people, from 80 nations, researchers from the University of Warwick and Dartmouth College in the US have found an extraordinarily consistent international pattern in depression and happiness levels that leaves us most miserable in middle age.
Their paper entitled "Is Well-being U-Shaped over the Life Cycle?" is to be published shortly in Social Science & Medicine, the world’s most-cited social science journal. The researchers found happiness levels followed a U shaped curve, with happiness higher towards the start and end of our lives and leaving us most miserable in middle age. Many previous studies of the life-course had suggested that psychological well-being stayed relatively flat and consistent as we aged.
In Britain unhappiness peaks at the same age for men and women. But in America unhappiness peaks 10 years later for men than for women. Why is that? Any guesses?
Using a sample of 1 million people from the UK, the researchers discovered that for both men and women the probability of depression peaks around 44 years of age. In the US they found a significant difference between men and women with unhappiness reaching a peak at around 40 years of age for women and 50 years of age for men.
Once full body rejuvenation becomes possible will people with youthful bodies feel happier than our current middle aged? Or will people feel compelled to stay in competition and hence feel frustrated? Maybe youthful people will spend decades and even centuries competing to get ahead with bodies and minds that are capable of allowing them to compete very intensely? Then again, maybe the robots will take over and wipe us out.
This unhappiness curve was found in a very large assortment of countries which have radically different economic conditions, customs, and laws. This suggests a biological cause rather than a social one.
They found the same U-shape in happiness levels and life satisfaction by age for 72 countries: Albania; Argentina; Australia; Azerbaijan; Belarus; Belgium; Bosnia; Brazil; Brunei; Bulgaria; Cambodia; Canada; Chile; China; Colombia; Costa Rica; Croatia; Czech Republic; Denmark; Dominican Republic; Ecuador; El Salvador; Estonia; Finland; France; Germany; Greece; Honduras; Hungary; Iceland; Iraq; Ireland; Israel; Italy; Japan; Kyrgyzstan; Laos; Latvia; Lithuania; Luxembourg; Macedonia; Malta; Mexico; Myanmar; Netherlands; Nicaragua; Nigeria; Norway; Paraguay; Peru; Philippines; Poland; Portugal; Puerto Rico; Romania; Russia; Serbia; Singapore; Slovakia; South Africa; South Korea; Spain; Sweden; Switzerland; Tanzania; Turkey; United Kingdom; Ukraine; Uruguay; USA; Uzbekistan; and Zimbabwe.
Find your country on the list?
The researchers found that some of the most obvious suspect factors were not the causes of mid-life unhappiness.
The authors, economists Professor Andrew Oswald from the University of Warwick and Professor David Blanchflower from Dartmouth College in the US, believe that the U-shaped effect stems from something inside human beings. They show that signs of mid-life depression are found in all kinds of people; it is not caused by having young children in the house, by divorce, or by changes in jobs or income.
I wonder if the mid-life unhappiness is due to the end of dreams of what is possible in youth combined with the need to struggle daily to get ahead. Then as people get older maybe they develop peace of mind about their lots in life and feel less dissatisfied about their stations in life. As brains age memory recall decreases and we lose imagination. Maybe with age a decaying ability to daydream also reduces dissatisfaction over what is as compared to what might be.
Maybe higher blood testosterone reduces the risk of bone fractures as you age.
Men over age 60 who have low blood testosterone levels may be at a higher risk for fractures, according to a report in the January 14 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
One-third of all osteoporotic fractures caused by porous bones occur in men, according to background information in the article. Men with a previous osteoporotic fracture have three to four times the risk of having another fracture than a woman of the same age with a fracture. “Preventing the first such fracture may have major public health implications,” the authors note. “Thus, understanding the determinants of fracture risk in men may reduce the burden of disease through facilitating better prevention strategies.”
Christian Meier, M.D., of the University of Sydney, Concord, New South Wales, Australia, and colleagues observed 609 men (average age 72.6) between January 1989 and December 2005. The men’s bone mineral density and lifestyle factors were recorded at the beginning of the study. Serum testosterone and estradiol (an estrogen) levels were measured and the occurrence of a low-trauma fracture (associated with a fall from standing height or less) was determined during follow-up.
Low-trauma fractures occurred in 113 men during follow-up with the risk of fracture significantly higher in those with low testosterone levels. “Twenty-five men experienced multiple incident fractures,” the authors note. “A total of 149 incident fractures were reported, including 55 vertebral, 27 hip, 28 rib, six wrist and 16 upper and 17 lower extremity fractures.”
“After adjustment for sex hormone−binding globulin (a blood protein), serum testosterone and serum estradiol levels were associated with overall fracture risk,” according to the authors. “After further adjustment for major risk factors of fractures (age, weight or bone mineral density, fracture history, smoking status, calcium intake and sex hormone−binding globulin), lower testosterone was still associated with increased risk of fracture, particularly with hip and non-vertebral fractures.”
The problem with this sort of study is that it doesn't prove the direction of cause and effect. Does poorer health contribute to both lower testosterone and greater risk of bone fracture? Would supplemental testosterone reduce risk fracture? If it did then would it not increase the risk of other health problems? Hard to say. What we really need: rejuvenating cell therapies and gene therapies that will work far better than the most optimistic benefit we could hope to derive from hormone therapy.
Don't get too much or too little sleep.
The study, authored by James E. Gangwisch, PhD, of Columbia University in New York, explored the relationship between sleep duration and the diagnosis of diabetes over an eight-to-10-year follow-up period between 1982 and 1992 among 8,992 subjects who participated in the Epidemiologic Follow-Up Studies of the first National Health and Nutrition Examination Survey. The subjects’ ages ranged from 32 to 86 years.
According to the results, subjects who reported sleeping five or fewer hours and subjects who reported sleeping nine or more hours were significantly more likely to have incident diabetes over the follow-up period than were subjects who reported sleeping seven hours, even after adjusting for variables such as physical activity, depression, alcohol consumption, ethnicity, education, marital status, age, obesity and history of hypertension.
The effect of short sleep duration on diabetes incidence is likely to be related in part to the influence of short sleep duration upon body weight and hypertension, said Dr. Gangwisch. Experimental studies have shown sleep deprivation to decrease glucose tolerance and compromise insulin sensitivity by increasing sympathietic nervous system activity, raising evening cortisol levels and decreasing cerebral glucose utilization. The increased burden on the pancreas from insulin resistance can, over time, compromise â-cell function and lead to type two diabetes, warned Dr. Gangwisch.
Too little sleep accelerates your aging.
Knowledge about how to slow your aging only helps if you act on it. Anyone going to change their sleep habits as a result of reading this?
CAMBRIDGE, England, Nov. 26 -- In otherwise healthy men, low testosterone is associated with an increased risk of death from any cause as well as from cardiovascular causes and cancer, researchers here said.
For all-cause mortality, each increase of six nanomoles of testosterone per liter of serum was associated with about a 14% drop in the risk of death, Kay-Tee Khaw, M.B.B.Ch., of the University of Cambridge School of Clinical Medicine, and colleagues reported in the Dec. 4 issue of Circulation.
These results come from a study on over eleven thousand men enrolled in the European Prospective Investigation into Cancer in Norfolk England. If you have low testosterone you especially ought to try to reduce other risk factors.
Lead author Dr Kay-Tee Khaw (University of Cambridge School of Clinical Medicine, UK) commented to heartwire: "This is the largest study of testosterone levels ever conducted. We don't know whether the association shown between higher levels of testosterone and lower mortality is causal or just a marker of something else, but regardless of this, it appears that low testosterone levels do identify a group at increased risk of cardiovascular death who could benefit from more aggressive treatments in terms of cholesterol and blood-pressure lowering."
Curiously, the men with higher testosterone did not appear to have higher risk of prostate cancer.
This result is consistent with some other recent studies on this topic. See my posts Low Testosterone Men Die More Rapidly and Low Testosterone Men Die Sooner.
Harvard economist Gregory Mankiw has an interesting article in the New York Times about medical spending. Differences in life expectancies between Americans and Canadians are not due to superior medical care under a socialist system.
The differences between the neighbors are indeed significant. Life expectancy at birth is 2.6 years greater for Canadian men than for American men, and 2.3 years greater for Canadian women than American women. Infant mortality in the United States is 6.8 per 1,000 live births, versus 5.3 in Canada.
These facts are often taken as evidence for the inadequacy of the American health system. But a recent study by June and Dave O’Neill, economists at Baruch College, from which these numbers come, shows that the difference in health outcomes has more to do with broader social forces.
For example, Americans are more likely than Canadians to die by accident or by homicide. For men in their 20s, mortality rates are more than 50 percent higher in the United States than in Canada, but the O’Neills show that accidents and homicides account for most of that gap.
Mankiw points out that Americans also have a higher incidence of obesity than Canadians. This makes Americans less healthy than Canadians. Mankiw wrote his article in order to make economic arguments about health care policy. But there's also a lesson here down below the level of national policy: The odds are that you can do far more for your health by improving your diet and lifestyle than you can by getting more health care. Think about that. Sure, there are people out there who would benefit from early detection of cancer or by taking statin drugs. But you probably could do more for your health by changing your diet and getting more exercise than by getting more medical care.
To put it another way: Medical treatments today have pretty severe limits on what they can accomplish. For many diseases we have no cures. For other diseases where cures are sometimes available the treatments have success rates well below 100%. You are better off adopting diet and lifestyle practices (more vegetables, more exercise) that will reduce your odds of getting sick in the first place. There's no magical place in the world (at least not yet) where either capitalism or socialism will supply you with cure-all health care.
Autoimmune disease rheumatoid arthritis is not just painful and debilitating. Sufferers of rheumatoid arthritis are not benefiting from the rising life expectancies which the rest of the American population is experiencing.
An autoimmune inflammatory disease that takes a progressive toll on the heart, kidney and liver as well as the joints, rheumatoid arthritis (RA) is associated with a high risk of early death. This sobering fact is well known. Less is known about whether longevity has improved for RA patients over the past few decades of remarkable improvements in longevity in the general population. Are earlier diagnosis, breakthrough drugs, and more aggressive antirheumatic treatment regimens paying off in terms of survival"
Okay, so RA doesn't just tear up your joints. It attacks your internal organs. No wonder RA sufferers have shorter life expectancies. But has the advance of modern medicine since the late 1950s done anything to increase the life expectancies of RA sufferers? No.
For answers to this vital question, researchers at the Mayo Clinic conducted a sweeping comparison of mortality trends among RA subjects with those in the general population. Their unsettling results, presented in the November 2007 issue of Arthritis & Rheumatism (http://www.interscience.wiley.com/journal/arthritis), underscore the urgent need to find strategies that will work to reduce the excess mortality consistently associated with RA.
Drawn from the comprehensive medical records of all residents of Olmsted County, Minnesota, 822 RA subjects were identified. The subjects included all residents of Rochester, Minnesota, first diagnosed with RA between January 1, 1955, and January 1, 1995, as well as all Olmsted County residents diagnosed with RA between January 1, 1995, and January 1, 2000. The subjects were 71.5 percent women, with a mean age of 57.6 years at RA incidence. All were followed up through their entire medical records until death or January 1, 2007. The median time of follow-up was 11.7 years, during which 445 of the RA subjects died.
Researchers compared the survival rates of patients diagnosed with RA in 5 time periods: 1955-1964, 1965-1974, 1975-1984, 1985-1994, and 1995-2000 using Cox regression models, adjusting for age and sex. In the 5 time periods, there was no significant difference in survival rates for RA subjects—which also means no significant gains in longevity.
Well that's bad. So what to do about it? If you don't already have rheumatoid arthritis (or other auto-immune disorders) then get more vitamin D for reduced RA risk (abstract here). Also, eat less red meat. Reduce your risks of debilitating and life shortening diseases. Eat a better diet.
Any thoughts on the mechanism behind this?
BRONX, NY – People with more years of education lose their memory faster than those with less education in the years prior to a diagnosis of dementia, according to a study by researchers at Albert Einstein College of Medicine of Yeshiva University, published in the October 23rd issue of the medical journal Neurology.
The study included 117 people who developed dementia out of an original cohort of 488. The researchers, led by Charles B. Hall, Ph.D., associate professor of epidemiology and population health at Einstein, followed study participants for an average of six years using annual cognitive tests. Study participants ranged in formal education levels of less than three years of elementary school to individuals with postgraduate education.
The study found for each additional year of formal education, the rapid accelerated memory decline associated with oncoming dementia was delayed by approximately two and one half months. However, once that accelerated decline commenced, the people with more education saw their rate of cognitive decline accelerate 4 percent faster for each additional year of education. The latter portion of this finding corroborates previous research, which had shown that people with more education had more rapid memory loss after diagnosis of dementia.
Maybe the smarter people can lose more neurons before they show symptoms of decay. Then their disease is more developed when they finally start showing symptoms and by then they are on a steeper later part of the declining slope.
I really want rejuvenation therapies for my brain. I'm so not looking forward to the intellectual decline of old age. But I'm hopeful that the accelerating pace of biotechnological advance will provide solutions before most of us become demented.
But levels above average do not help and so don't go hog wild with the testosterone.
Older men with low levels of testosterone may have an increased long-term risk of death compared to men with normal testosterone, according to a new study accepted for publication in the Journal of Clinical Endocrinology & Metabolism (JCEM).
"This is the first report linking low levels of testosterone with earlier death in relatively healthy older men,” said Gail Laughlin, Ph.D., assistant professor at the University of California San Diego. “These results do not suggest testosterone supplementation for all older men, because levels above average did not make a difference.”
This study involved 794 men, ages 50 to 91 years, who were living in a southern California community and who participated in the Rancho Bernardo Study in the 1980s. Men whose total testosterone levels at the beginning of the study were in the lowest quartile (<241 ng/dl) were 40 percent more likely to die over the next 18 hears than those with higher levels. This difference was not explained by age, illness, adiposity, or lifestyle.
“We want to emphasize that this is an observational study,” said Laughlin. “We cannot recommend that any man take testosterone based on these results. Only randomized clinical trials can determine whether testosterone supplements are safe and can promote longevity. In the meantime, lifestyle changes to prevent or decrease obesity may also extend longevity."
Approximately 30 percent of men 60 years and older are estimated to have low testosterone, which is often accompanied by symptoms such as low bone and muscle mass, increased fat mass, low energy, and impaired physical, sexual, and cognitive function.
Keep in mind that boosting testosterone might boost your risk of prostate cancer. We need much more detailed information about hormone supplement therapies. Probably they are a net benefit for some people and a net harm for others. We can't predict accurately enough who will gain and who will lose from assorted hormone replacements.
On average 6.7% of the US workforce has arthritis severe enough to limit their ability to work.
Persons who are limited in their work by arthritis are considered to have arthritis-attributable work limitation (AAWL). In the United States, AAWL affects one in 20 working-age adults (aged 18--64 years) and one in three working-age adults with self-reported, doctor-diagnosed arthritis (2). To estimate state-specific prevalence of AAWL and the percentage employed among working-age U.S. adults with AAWL, CDC analyzed data from the 2003 Behavioral Risk Factor Surveillance System (BRFSS) survey. This report describes the results of that analysis, which indicated that the state-specific prevalence of AAWL among all working-age adults ranged from 3.4% (Hawaii) to 15.0% (Kentucky) (median among states: 6.7%) in 2003. Among those with self-reported, doctor-diagnosed arthritis, the prevalence of AAWL ranged from 25.1% (Nevada) to 51.3% (Kentucky) (median among states: 33.0%). In every state, persons with work limitations attributed to arthritis reported being employed less frequently than working-age adults in the state overall and persons with arthritis but not work limitations.
The percentages will rise as average age rises. Therefore the benefits of effective treatments will rise as well. Therefore we stand more to gain from developing treatments as our population ages.
Rejuvenation therapies such as gene therapies and stem cell treatments will some day slash the rate of disability caused by arthritis and could also slash disability caused by other degenerative diseases. We would each suffer less and produce more and make more money and live better lives if those therapies came sooner rather than later. I personally am convinced by the argument that we can stop and reverse aging of joints and of the rest of the body.
Widespread use of influenza vaccines haven't lowered death rates among old folks.
Researchers are questioning how much the flu vaccine prevents flu-related deaths among older people, saying it may provide less protection starting around age 70, as immune systems decline with age.
In a review article in the October issue of Lancet Infectious Diseases, researchers including Dr. Lisa Jackson, a senior investigator at the Group Health Center for Health Studies, say evidence that all older people should get flu vaccines is weak.
Read the full article for the details.
The problem is rickety old immune systems.
A further piece of research found that over-65s produced only half or a quarter of the antibodies to flu vaccines that younger people did. Vaccination coverage has risen steeply in the US, from 15% of the target population in 1980 to 65% today, they write. But there has been no matching drop in influenza deaths.
We need the ability to rejuvenate our immune systems. In particular we need a way to kill old immune cells that are too worn out so that healthier immune cells can take their place. Plus, we need the ability to grow replacement thymus glands. All of this will come with time. But we could get these advances sooner if we pushed harder for them.
For most of the remaining unconquered diseases we aren't going to cure them or prevent them without developing the ability to do rejuvenation on each portion of the body which malfunctions with each disease. Attempts to cure the many diseases and disorders of old age will inevitably lead to efforts to rejuvenate various malfunctioning parts of the body. Successful efforts to rejuvenate various parts of the body will lead us to the point where we can fix so many parts that full body rejuvenation becomes possible.
In Europe more people are killed by cold weather than by warm weather.
How will heat and cold deaths change over the coming century with global warming? Let us for the moment assume—very unrealistically—that we will not adapt at all to the future heat. Still, the biggest cross-European cold/heat study concludes that for an increase of 3.6 degrees Fahrenheit in the average European temperatures, “our data suggest that any increases in mortality due to increased temperatures would be outweighed by much larger short-term declines in cold-related mortalities.” For Britain, it is estimated a 3.6°F increase will mean 2,000 more heat deaths but 20,000 fewer cold deaths. Likewise, another paper incorporating all studies on this issue and applying them to a broad variety of settings in both developed and developing countries found that “global warming may cause a decrease in mortality rates, especially of cardiovascular diseases.”
Mind you, this benefit of warmer weather might not be found in Africa, the Middle East, the Indian subcontinent, or other already very warm places.
In industrialized countries air conditioning appears to have decreased deaths from heat.
Yet something great happened in the decades following. Death rates in Philadelphia and around the country dropped in general because of better health care. But crucially, temperatures of 100°F today cause almost no excess deaths. However, people still die more because of cold weather. One of the main reasons for the lower heat susceptibility is most likely increased access to air-conditioning. Studies seem to indicate that over time and with sufficient resources, we actually learn to adapt to higher temperatures. Consequently we will experience fewer heat deaths even when temperatures rise.
Indeed humans live longer in warmer weather and cold weather seems to wear us out more quickly if we believe a paper by Olivier Deschenes and Enrico Moretti and published by the National Bureau of Economic Research:, Extreme Weather Events, Mortality and Migration.
We estimate the effect of extreme weather on life expectancy in the US. Using high frequency mortality data, we find that both extreme heat and extreme cold result in immediate increases in mortality. However, the increase in mortality following extreme heat appears entirely driven by temporal displacement, while the increase in mortality following extreme cold is long lasting. The aggregate effect of cold on mortality is quantitatively large. We estimate that the number of annual deaths attributable to cold temperature is 27,940 or 1.3% of total deaths in the US. This effect is even larger in low income areas. Because the U.S. population has been moving from cold Northeastern states to the warmer Southwestern states, our findings have implications for understanding the causes of long-term increases in life expectancy. We calculate that every year, 5,400 deaths are delayed by changes in exposure to cold temperature induced by mobility. These longevity gains associated with long term trends in geographical mobility account for 8%-15% of the total gains in life expectancy experienced by the US population over the past 30 years. Thus mobility is an important but previously overlooked determinant of increased longevity in the United States. We also find that the probability of moving to a state that has fewer days of extreme cold is higher for the age groups that are predicted to benefit more in terms of lower mortality compared to the age groups that are predicted to benefit less.
Global warming, by decreasing exposure to cold weather, should therefore increase life expectancies of people who now live in colder climates.
I wonder whether the real benefit of a southward migration is reduced exposure to the cold or increased exposure to the rays of the sun. Greater sunlight exposure reduces depression and also increases vitamin D production and therefore reduces incidence of cancer and other diseases. But even if life expectancy benefit comes from more sunlight exposure a warming of northern climes will get people outside sooner in springtime and hence up their vitamin D production.
Cold weather also probably reduces levels of exercise. Plus, in warmer climes locally grown vegetables and fruits are available more of the year. So diets might be better in warmer areas of industrialized countries.
Some people profess to be disgusted by the sight of old men seducing young fertile women. But some biologists and anthropologists at Stanford University and UC Santa Barbara argue that the success of old men managing to impregnant younger women drove human evolution to extend human life expectancy.
Evolutionary theory predicts that senescence, a decline in survival rates with age, is the consequence of stronger selection on alleles that affect fertility or mortality earlier rather than later in life. Hamilton quantified this argument by showing that a rare mutation reducing survival is opposed by a selective force that declines with age over reproductive life. He used a female-only demographic model, predicting that female menopause at age ca. 50 yrs should be followed by a sharp increase in mortality, a “wall of death.” Human lives obviously do not display such a wall. Explanations of the evolution of lifespan beyond the age of female menopause have proven difficult to describe as explicit genetic models. Here we argue that the inclusion of males and mating patterns extends Hamilton's theory and predicts the pattern of human senescence. We analyze a general two-sex model to show that selection favors survival for as long as men reproduce. Male fertility can only result from matings with fertile females, and we present a range of data showing that males much older than 50 yrs have substantial realized fertility through matings with younger females, a pattern that was likely typical among early humans. Thus old-age male fertility provides a selective force against autosomal deleterious mutations at ages far past female menopause with no sharp upper age limit, eliminating the wall of death. Our findings illustrate the evolutionary importance of males and mating preferences, and show that one-sex demographic models are insufficient to describe the forces that shape human senescence.
Read the full research paper (free access at Plos One) for all the details.
Older Canadian men need to try harder to apply selective pressures for longer life. The brutal Amazonian Yanomamo men show this can be done.
Male fertility is nonzero till ages 55 yrs in Canada and the !Kung, 65 yrs in the Ache, 70 yrs in the Yanomamo, 60 yrs in the Tsimane, and 75 yrs in the Gambia.
So, look, you have a life expectancy that extends into the 70s or 80s because old guys managed to knock up young hot babe women. Is this upsetting? Disgusting? Reality can sometimes be that way (to quote Jello Biafra of the Dead Kennedys).
Nowadays the best ways to extend life are to develop great stem cell therapies and gene therapies. We should pursue those therapies with all the determination and gusto that old men of yesteryear (and of today) spent trying to bed young fertile women.
Update: As regular readers know, I try to look for practical ways to apply lessons I learn from reading about scientific progress. This report is no exception. I now feel obliged to knock up a beautiful woman once I reach 65 years old. I'm going to do it because I support eugenics for a longer lived human species.
Down with aging. First people gain weight and then their muscles start dissolving into fat.
Researchers have discovered that middle age spread seems to have an effect on waistlines but not weight as people get older.
Researchers, funded by the Medical Research Council, have found that people in early middle age seem to put on more weight more quickly than people slightly older. But the waistlines of the older group seem to grow more quickly.
The stage when the waistlines start expanding more rapidly is when the muscles wither.
One of the researchers Geoff Der, from the MRC’s Social and Public Health Sciences Unit in Glasgow explained:
“As people get older it seems that their bodies change… they lose muscle and get fatter – this explains why middle-age spread might not be reflected on the bathroom scales.”
He goes on: “This challenges the traditional method of measuring how fat a person is: the body mass index. The BMI is a good measure of lean body tissue, but an expanding waistline may be a more reliable measure of the amount of fatty tissue a person has gained. Although the people in the older middle age group in this study appeared to put on less weight than the younger people, their waist circumferences continued to grow over time. What appears to have been happening is that the increase in fat was being obscured by a loss of muscle mass.’’
So first you gain weight. Then your weight gain slows but some of your muscle mass gradually converts to fat. How disgusting. Really, we need rejuvenation therapies. Aging takes away your muscles and makes you fat. This is something we can do without. We should support bigger efforts to figure out how to avoid the decay of aging.
When you head into middle age the odds of keeping the weight off are definitely against you.
The researchers carried out a nine-year study of 1044 people aged either 39 or 59 in 1991. The height, waist circumference and weight of each participant was measured in 1991, 1995 and 2000, and used to measure changes in body mass index over time.
Only one in five (20%) of the people maintained a stable weight as the study progressed. Steady weight gain was measured in the younger group, more than 42% of study participants put on 10kg, 17% gained 5kg.
On average, both men and women in the younger group gained between 0.5kg and 1kg a year. This weight gain was fastest in their younger years. Those in the older age group gained least weight in the second half of the study, however, although their overall weight may not have changed their waist circumference did.
Aging is bad. The physical changes that come from the accumulation of damage to your body are a big and increasing negative. I'm talking downsides. I'm talking losses. Something to be avoided.
We need to seriously try to develop treatments that will reverse the aging process. The defeat of aging is an achievable goal and it is a goal that will be achieved in this century. But whether it comes soon enough for most of us depends on how hard we push to achieve it.
I hear the Beatles singing. "All the lonely people, where do they all come from? All the lonely people, where do they all belong?" University of Chicago psychologists Louise Hawkley and John Cacioppo find that lonely people find life more stressful.
However, when the psychologists looked at the lives of the middle-aged and old people in their study, they found that although the lonely ones reported the same number of stressful life events, they identified more sources of chronic stress and recalled more childhood adversity. Moreover, they differed in how they perceived their life experiences. Even when faced with similar challenges, the lonelier people appeared more helpless and threatened. And ironically, they were less apt to actively seek help when they are stressed out.
I also hear Mr. Mackey: "Stress is bad, mmmkay?" (not that he ever said that to my knowledge)
Loneliness cranks up a stressful flight-or-flight chemical state.
Hawkley and Cacioppo then took urine samples from both the lonely and the more contented volunteers, and found that the lonely ones had more of the hormone epinephrine flowing in their bodies. Epinephrine is one of the body’s “fight or flight” chemicals, and high levels indicate that lonely people go through life in a heightened state of arousal. As with blood pressure, this physiological toll likely becomes more apparent with aging. Since the body’s stress hormones are intricately involved in fighting inflammation and infection, it appears that loneliness contributes to the wear and tear of aging through this pathway as well.
Feeling lonely? That stress ages your body more rapidly.
Lonely people don't sleep as well.
There is more bad news. When we experience the depletion caused by stress, our bodies normally rely on restorative processes like sleep to shore us up. But when the researchers monitored the younger volunteers’ sleep, they found that the lonely nights were disturbed by many “micro awakenings.” That is, they appeared to sleep as much as the normal volunteers, but their sleep was of poorer quality. Not surprisingly, the lonelier people reported more daytime dysfunction. Since sleep tends to deteriorate with age anyway, the added hit from loneliness is probably compromising this natural restoration process even more.
You can read the original paper (paid access).
Seeking an end to your loneliness seems akin to seeking a medical treatment.
I also hear Roy Orbison singing "Only The Lonely".
There goes my baby, there goes my heart
They’re gone forever, so far apart
But only the lonely know wh-y-y I cry--only the lonely
Get moderate amounts of exercise for more lasting benefits.
DURHAM, N.C. – Scientists examining the relationship between the intensity and length of a workout and the duration of its benefits have made a surprising discovery: More isn't necessarily better, and none may be worse than we ever imagined.
"On the surface, it seems to make sense that the harder we exercise, the better off we'll be, and by some measures that's true," says lead author Cris Slentz, Ph.D, an exercise physiologist at Duke University Medical Center. "But our studies show that a modest amount of moderately intense exercise is the best way to significantly lower the level of a key blood marker linked to higher risk of heart disease and diabetes. More intense exercise doesn't seem to do that."
What may be even more remarkable, he says, is that some of the benefits derived from a modest exercise regimen appear to last much longer than those gained from a more rigorous program.
Triglyceride lowering benefits of exercise were longer lasting for those who only exercised moderately.
The researchers found that for the most part, no amount of exercise significantly changed LDL levels. HDL levels, however, tended to improve with the length and intensity of the workout, and that the benefit was sustained over time.
But perhaps the most interesting finding was that a modest, low-intensity workout – walking just 30 minutes per day, for example, dramatically lowered triglyceride levels. Triglycerides are the particles that carry fat around in the body, and they're also a good indicator of insulin resistance, a marker for diabetes. Lowering triglyceride levels lowers risk of heart disease and diabetes.
"A proper exercise program appears to be able to lower a person's insulin resistance in just a matter of days," says Kraus. "We were also amazed to see that the lower triglyceride levels stayed low even two weeks after the workouts ended." Longer, more intense workouts didn't have nearly the same impact, they say.
Wear your moles proudly, knowing you enjoy a biochemical advantage over your less moley brethren.
People with large numbers of moles may age slower than expected, according to a study from King's. Researchers studied the skin and telomere length (a marker of biological ageing found on all cells in the body) of more than 1800 twins and found that people with a high number of moles had longer telomeres.
The 10 year study from the Twin Research Unit was funded by the Wellcome Trust and is published in the July edition of Cancer Epidemiology Biomarkers & Prevention.
...
The researchers compared telomere length measurements in white cells with the number of moles in more than 1800 female twins (900 pairs of twins) aged between 18 and 79 years. They found that those with high numbers of moles (greater than 100) had longer telomeres than those with very few moles (fewer than 25). The difference between the two mole groups was equivalent to six to seven years of normal ageing (estimated by looking at the average rate of telomere length loss per year in the whole group). This was not affected by other factors such as age, weight or smoking.
These results suggest those with higher numbers of moles may have a delayed ageing as they have longer telomeres and appear to keep their moles for longer. In contrast, people with shorter telomeres have lower numbers of moles and appear to lose them quicker with age - which may be a marker of accelerated ageing.
Lead researcher Dr Veronique Bataille says: ‘The results of this study are very exciting as they show, for the first time, that moley people who have a slightly increased risk of melanoma may, on the other hand, have the benefit of a reduced rate of ageing. This could imply susceptibility to fewer age-related diseases such as heart disease or osteoporosis, for example. Further studies are needed to confirm these findings.'
We need follow-up population studies to measure life expectancy for those who have more and fewer moles. But telomere is a pretty good proxy for rate of aging. On that score see my posts Chronic Stress Accelerates Aging As Measured By Telomere Length and Telomere Length Indicates Mortality Risk.
If the melanin content of moles slows down general body aging why is that? After all, most of the body is not moles. Even most of the skin is not moles. So how could the presence of moles confer much protective effect? Are the moles a proxy for more melanin inside the body?
Could we slow the rate of aging by inducing most of our cells to produce more melanin?
Men with lower testosterone in their 50s and beyond do not live as long.
Low levels of testosterone may increase the long-term risk of death in men over 50 years old, according to researchers with the Department of Family and Preventive Medicine at the University of California, San Diego School of Medicine.
“The new study is only the second report linking deficiency of this sex hormone with increased death from all causes, over time, and the first to do so in relatively healthy men who are living in the community,” said Gail Laughlin, Ph.D., assistant professor and study author.
This result surprises me. I would have expected the testosterone to reduce life expectancies by upping the incidence of prostate cancer and by basically turning up the body's metabolism to a level that would cause the body to wear out more rapidly.
The men in this study have been tracked for the last 18 years.
“We have followed these men for an average of 18 years and our study strongly suggests that the association between testosterone levels and death is not simply due to some acute illness,” said Laughlin.
In the study, Laughlin and co-workers looked at death, no matter the cause, in nearly 800 men, ages 50 to 91 years, who were living in Rancho Bernardo, California. The participants have been members of the Rancho Bernardo Heart and Chronic Disease Study since the 1970s. At the beginning of the 1980s, almost one-third of these men had suboptimal blood testosterone levels for men their age.
The group with low testosterone levels had a 33 percent greater risk of death during the next 18 years than the men with higher testosterone. This difference was not explained by smoking, drinking, physical activity level or pre-existing diseases (such as diabetes or heart disease).
In this study, "low testosterone" levels were set at the lower limit of the normal range for young adult men. Testosterone declines slowly with aging in men and levels vary widely, with many older men still having testosterone levels in the range of young men. Twenty-nine percent of Rancho Bernardo men had low testosterone.
So them maybe testosterone patches would increase life expectancy in men who have lower levels of testosterone?
The men with lower testosterone had more fat on their wastes and more inflammation in their bodies.
Men with low testosterone were more likely to have elevated markers of inflammation, called inflammatory cytokines, which contribute to many diseases. Another characteristic that distinguished the men with low testosterone was a larger waist girth along with a cluster of cardiovascular and diabetes risk factors related to this type of fat accumulation.
This begs the question: If these low testosterone men took testosterone would their inflammation markers go down and their fat decrease? If so, would they then live longer? I would at least expect the reduction in body fat.
Jane Brody of the New York Times outlines some of the dismal details of eye aging.
How well do you see at night? If you're over 50, probably not as well as you think, no matter how many carrots you eat. The typical 50-year-old driver needs twice as much light to see as well after dark as a 30-year-old.
That is both inconvenient and dangerous. Some people are content to grow old and even try to justify the changes which happen to our bodies as the various pieces break down. But the changes to our bodies due to aging all seem like losses to me and with no compensating upside.
The tiny muscles in your irises become less able to adjust pupil sizes and so your pupils can't dilate as far and as quickly to let in more or less light as needed. As far as I'm concerned this is yet another argument for treating the development of rejuvenation therapies as an urgent matter deserving a massive research push.
In dim light or darkness, eyes adapt by widening the pupils to let in as much light as possible. The iris (the colored part of the eye surrounding the pupil) contains tiny muscles that control the size of the pupil. As you get older, these muscles (like most in the body) weaken and do not respond as well to the need to let in more light. The result is a small pupil when you try to see in poor light. It's as if your eyes were still young but you were wearing sunglasses at night.
Does the world seem darker as you get older? It literally is as far as the retinas of your eyes are concerned.
According to one account I found you start out with about 120 million rods for black/white seeing. You also start with about 6 to 7 million cones of 3 types for color sensitivity. The rods age more rapidly and hence the black/white night-time vision deteriorates so much.
There is also evidence that as we age we lose more rods than cones. In the young eye, rods outnumber cones by nine to one in the part of the retina called the macula. But an autopsy study of older adults found that while the cones remained intact, almost a third of the rods in the macula had been lost.
Plus, pigment production for rods slows as you age. Also, your lenses become more cloudy as UV light causes cross linkages to form in the lenses.
The diminished number of rods may be a factor, but in addition, the light-sensitive pigment in the rods regenerates more slowly in older eyes.
Another common change in older eyes is a gradual clouding of the lens - the formation of cataracts - which makes the lens less transparent and reduces the amount of light reaching the retina.
Some labs are working on designs of artificial replacement lenses. Also, other labs are working on ways to grow natural replacement lenses using cells and tissue engineering. One way or another we'll some day be able to replace aged lenses with lenses as young as those of a baby.
But we need much more in order to do eye rejuvenation. First off, we need cell therapies created from stem cells to send in youthful replacement muscle cells in the iris and around the eyeball. Plus, gene therapies might reinvigorate some of the aged eye muscle cells so as to avoid need for their replacement.
Aging muscles in the rest of the body also suffer from deaths of nerves that connect to them. This probably happens with eyeball muscles as well. So we might need cell therapies that grow new neurons to hook up to rejunvenated eyeball muscles.
We also need replacement cells for making rod pigments. Plus, we need cell therapies to replace lost rods and cones. Replacement rods and cones will need new nerve connections to them. Rejuvenation therapies that repair existing rods and cones would reduce the need for replacement neural connections by avoiding the loss of target rods and cones which the original eye neurons formed connections to.
We'll also need replacement cells for eye blood vessels so that the eye cells get plenty of nutrients. Creation of replacement vascular cells might also reduce the incidence of Age-related macular degeneration (AMD) diseases of the eye which involve aged arteries in the eye. On AMD Lou Pagnucco points me to a study which finds a role for excessive zinc deposits in the eye as contributors to AMD. We might also need therapies that remove built up zinc deposits.
Further on down the road we'll eventually witness the development of tissue engineering technologies so advanced that they can grow whole organ replacement parts. Replacement eyeballs will then provide much more thorough and comprehensive solutions to the problems of aging eyes. Though even if such eyeballs could be grown today we'd face the extremely difficult problem of how to hook up a replacement eyeball to all the nerves that stretch into eyes. Repairing our existing eyes might remain preferable many years due to the difficulty in connecting up new replacement eyes.
Your odds of reaching 85 are 69% if you avoid all the risk factors spelled out below.
Avoiding health risk factors in midlife such as smoking, being overweight, excessive drinking and hypertension is associated with a longer and healthier life in men, according to a study in the November 15 issue of JAMA, a theme issue on men's health.
Bradley J. Willcox, M.D., of the Pacific Health Research Institute and Kuakini Medical Center in Honolulu, presented the findings of the study today at a JAMA media briefing on men's health in New York.
Persons alive at age 85 years or older are the fastest-growing age group in most industrialized countries and are among the largest consumers of health care resources. Identifying strategies for remaining healthy, vigorous, and disability-free at older ages has become a major priority, according to background information in the article. Studies with substantial numbers of long-lived participants and characteristics associated with longer survival are rare but essential to identify risk factors for health and survival at older ages.
Dr. Willcox and colleagues examined potential biological, lifestyle, and sociodemographic risk factors present at middle-age to identify risk factors for healthy survival. The study included 5,820 Japanese-American middle-aged men (average age, 54) in the Kuakini Honolulu Heart Program/Honolulu Asia Aging Study. The participants were free of illness and functional impairments and were followed for up to 40 years (1965-2005) to assess overall and exceptional survival. Exceptional survival was defined as survival to a specified age (75, 80, 85, or 90 years) without incidence of 6 major chronic diseases and without physical and cognitive impairment. The diseases were coronary heart disease, stroke, cancer (excluding nonmelanoma skin cancer), chronic obstructive pulmonary disease, Parkinson disease, and treated diabetes. Of the 5,820 original participants, 2,451 participants (42 percent) survived to age 85 years and 655 participants (11 percent) met the criteria for exceptional survival to age 85 years.
Here are the core factors you have to work on to increase your odds of reaching 85.
The researchers found that high grip strength and avoidance of overweight, hyperglycemia, hypertension, smoking, and excessive alcohol consumption were associated with both overall and exceptional survival. In addition, high education and avoidance of hypertriglyceridemia (elevated triglyceride level) were associated with exceptional survival, and lack of a marital partner was associated with death before age 85 years.
Get married, stop smoking, build muscle strength, don't drink too much alcohol, eat a diet that keeps your triglycerides down. These are all known risk factors already.
Avoid all the risk factors and your odds of reaching 85 are very high.
Risk factor models based on cumulative risk factors (survival risk score) suggest that the probability of survival to age 85 years is as high as 69 percent with no risk factors and as low as 22 percent with 6 or more risk factors. The probability of exceptional (healthy) survival to age 85 years was 55 percent with no risk factors but decreased to 9 percent with 6 or more risk factors
Rejuvenation therapies are coming. The longer you can keep yourself alive the greater the odds you'll still be around when therapies that reverse aging make it to market.
Stress can have repercussions later in life in the form of chronic fatigue, according to a new study from Karolinska Institutet. People who considered their lives to be stressful at the start of the 1970s today suffer more often from chronic fatigue than others. The study was carried out with data from the Swedish Twin registry.
Chronic fatigue is a condition characterised by long-lasting and abnormal exhaustion, often accompanied by concentration impairment, mood swings, insomnia and pain in the muscles and joints. Despite extensive research, no root causes have been identified; all that scientists know so far is that it seems to appear across all ages and social classes in many different countries.
A research group from Karolinska Institutet has now been able to show that one of the direct causes of chronic fatigue is stress. Using the results from a health survey conducted amongst almost 20,000 twins from the Swedish Twin registry in 1973 and of a repeat survey of the same population in 1998 (which contained questions about chronic fatigue), the researchers found that the group who claimed to have stressful lives 25 years previously ran a 65 per cent greater chance of developing chronic fatigue than those who did not.
The scientists also noted a correlation between emotional instability and chronic fatigue. By limiting the analysis to identical twins, the researchers were able to dismiss any causal relationship. Instead, the correlation should be interpreted as there being genetic factors that are important for both emotional instability and chronic fatigue. Using the same method, the team has been able to show that stress does actually have a direct impact on the risk of developing chronic fatigue.
Chronic stress also accelerates aging as measured by chromosome telomere length. Telomeres get shorter with age and shorten more rapidly in people who suffer from chronic stress.
Some people feel more alive and productive under pressure. But if you feel chronically under pressure you are setting yourself up to age more rapidly and get debilitating illnesses.
Some scientists theorize that gum disease contributes to the development of atherosclerosis and heart disease. Here's another piece of evidence for the argument that you really ought to floss more often.
CHICAGO -- Researchers found an increased risk of coronary heart disease for people below the age of 60 who have more than four millimeters of alveolar bone loss (the bone that holds the teeth in the mouth) from periodontal disease, according to a new study that is printed in the Journal of Periodontology.
It was found that participants with coronary heart disease had an increase of periodontal disease indicators, including alveolar bone loss, clinical attachment loss and bleeding compared to the group without coronary heart disease.
"This study is distinctive because to our knowledge, it is the first to include both the alveolar bone loss and full mouth recording of clinical attachment loss as measurements of periodontal disease," explains Dr. Karen Geismar, Department of Periodontology, School of Dentistry, Faculty of Health Science, University of Copenhagen, Denmark. "Alveolar bone loss was recently found to be the periodontal variable that had the strongest association to coronary heart disease."
The association between periodontal disease and coronary heart disease has been that chronic infections and the inflammatory response from diseases such as periodontal disease may be involved in the initiation and progression of atherosclerosis.
I'm partial to toothpicks. Flossing is too distracting.
How much do chronic infections contribute to cardiovascular disease? The answer may vary by genetic make-up. A research group has a grant to try to find genetic factors which interact with infections to influence cardiovascular disease risk.
Dr. Harald Göring, principal investigator of the new $1.9 million grant from the National Heart, Lung and Blood Institute, titled “Genetics of Infection and Its Relation to CVD Risk,” says there has not been extensive research on the role infections play in the risk for cardiovascular disease. However, a number of epidemiological studies have shown a higher-than-average prevalence of infections among people who have suffered heart attacks, strokes, and a variety of other ailments.
Some common pathogens might contribute to heart disease risk. But some people might carry genetic variations that make them immune to these common pathogens.
These pathogens include Chlamydia pneumonia, a common cause of pneumonia; Helicobacter pylori, a major cause of ulcers; Porphyromonas gingivalis, commonly associated with gum disease; hepatitis A virus, most commonly spread among school-age children and young adults; herpes simplex virus 1, the cause of cold sores; Cytomegalovirus, or human herpesvirus 5, which particularly affects the salivary glands; and human herpesvirus 8, which induces Kaposi sarcoma in persons with immunodeficiency.
“What we want to know is, since these pathogens are so common and so easily spread, how have some people managed to avoid infection?” asked Göring. “Everyone has been exposed to them, but some people don’t have antibodies for them in their bloodstream, indicating that they’ve never been infected with these pathogens and mounted an immune response. So they may have some innate resistance to infection, some other way of preventing infection in the first place. That could be due to a difference in their genetic makeup.”
In a pilot study with 600 individuals from the San Antonio Family Heart Study, Göring has already shown evidence that there are genetic variants on chromosome 21 that influence susceptibility to Chlamydia pneumonia. Now he wants to look for genetic influences on susceptibility to all seven pathogens in a larger study population.
If pathogens contribute to the development of atherosclerosis and heart disease then we can develop counters such as vaccines, antibiotics, and even gene therapies to enhance immune systems. Plus, we can brush our teeth more often.
Update: While the influence of various pathogens on cardiovascular disease risk remains to be proven the claim that fruits and vegetables lower heart disease risk is based on a much larger body of evidence.
The analysis, published in the current issue of the Journal of Nutrition (Vol. 136, pp. 2588-2593), found that the risk of coronary heart disease (CHD), conditions that cause of 20 per cent of deaths in the US and 17 per cent of deaths in Europe, was cut by four per cent for each additional fruit and vegetable portion consumed, and by seven per cent for fruit portion intake.
The link between the risk of CHD and vegetable intake however was mixed with a more beneficial relationship observed for general cardiovascular mortality (26 per cent risk reduction) than for the more specific fatal and nonfatal heart attacks (myocardial infarction) (five per cent).
I wonder why the bigger benefit from fruits. Anthocyanins?
A pair of studies in the New England Journal of Medicine find that contrary to a controversial CDC study (more on it here) released last year being overweight (which is less heavy than being obese) really does shorten life expectancy.
Being overweight during midlife is associated with an increased risk of death, according to a new study conducted by the National Cancer Institute (NCI), part of the National Institutes of Health, in collaboration with AARP, the nation's leading organization for persons 50-Plus. Results of the study appear in the August 24, 2006, issue of the New England Journal of Medicine*.
Previous research had established a link between obesity and increased risk of death, but whether a relationship also existed between being overweight and increased risk of death remained uncertain. In 2004, the Centers for Disease Control and Prevention (CDC) reported that 34.1 percent of the U.S. adult population was overweight, but not obese**. Overweight and obesity are defined using a measurement called body-mass index (BMI), calculated as a person's weight divided by the square of their height. A BMI of 18.5 - 25.0 is considered normal, whereas people who have a BMI of 25.0 - 29.9 are considered overweight, and individuals with a BMI over 30.0 are regarded as obese. (Click to view BMI chart)
The NIH-AARP Diet and Health Study of 527,265 monitored the health status of Americans from 1995 through 2005 via mailed questionnaires and by surveying death records. When the analysis focused on BMI at age 50 among persons who had never smoked, the researchers, led by Kenneth F. Adams, Ph.D., of NCI's Division of Cancer Epidemiology and Genetics, found that the risk of mortality among participants who were overweight increased by 20 to 40 percent. Mortality risk among obese participants increased two to three-fold.
"BMI at age 50 gives a more accurate representation of the amount of excess fatness a person was exposed to over decades," said Michael F. Leitzmann, M.D., NCI, senior author of the study. "On the other hand, body weight reported at age 65, for example, might reflect a recent weight loss due to cancer or other disease. If that person then dies the next year, it would be inaccurate to classify that person in the normal BMI range when their pre-cancer BMI was actually overweight."
I think their focus on BMI before major illneseses develop is the correct approach. As people get older and sicker health problems start influencing body weight and weight becomes as much an effect as a cause of health status..
They also aimed at getting data on non-smokers in order to avoid weight reduction caused by smoking.
Some earlier studies have shown that being overweight was not associated with an increased risk of death. However, smoking and chronic illness are associated with a lower BMI and an increased risk of death, which may distort the relationship between BMI and mortality.
An advantage of the current study was the availability of data on more than 186,000 male and female participants who had never smoked. This allowed the researchers to untangle the complex relationships between body weight, smoking, existing disease, and risk of death. Other possible confounding factors that were accounted for included age, race or ethnic group, level of education, physical activity, and alcohol intake.
This result is not surprising given what we know about blood lipid levels and other aspects of metabolism among the overweight and obese.
A study on a Korean population found higher mortality with either high or low BMI.
While studies have linked being either underweight or overweight to poor health, the effect of being overweight or obese on the risk of dying has been a topic of recent controversy. Researchers have long used the body-mass index (BMI), weight in kilograms divided by the square of height in meters, as a measure of the appropriateness of weight in relation to height. Researchers from Yonsei University, in Seoul, South Korea, and the Johns Hopkins Bloomberg School of Public Health report in one of the largest studies to date (over 1.2 million study participants) that having either a high or low BMI increases risk of death. The researchers found that the effect of BMI on the risk of dying varied among major causes of death and that the risk of death from being overweight or obese was greater in younger people. The study is published in the Aug. 24, 2006, edition of the New England Journal of Medicine.
While higher BMI values was associated with less respiratory causes of death the higher BMI values were associated with higher rates of cancer and heart diease. Note that cancer and heart diseases are the two biggest killers.
The researchers found that the relationship of BMI with risk of dying varied among the major causes of death considered. The risk of death from cancer increased beginning at BMI levels of 26.0-28.0 and rose further at higher levels, according to the researchers. Risk for death from respiratory causes was highest at the lowest BMI values and decreased with higher BMI values, whereas the risk of death from atherosclerotic cardiovascular disease increased progressively with higher BMI values. Information on cardiovascular risk factors showed an increasingly unfavorable profile with increasing BMI values. Study participants younger than 50 years of age had the highest relative risk of death associated with a high BMI. The researchers report no evidence of an increased risk of death for 65-year-old and above, obese individuals.
Dr. Meir Stampfer, chairman of the epidemiology department at the Harvard School of Public Health who was not involved in either study, called both articles fine.
“They show quite convincingly, yet again, that overweight and, in particular, obesity, raise the risk of mortality,’’ Dr. Stampfer said. “It really should be the final word on this issue that’s arisen as to whether overweight is actually bad for you or not.”
For overweight people losing weight and keeping it off is hard. Drugs to suppress appetite will increase life expectancy.
Men with low testosterone are at greater risk of dying than men with normal testosterone.
Men who have a low testosterone level after age 40 may have a higher risk of death over a four-year period than those with normal levels of the hormone, according to a report in the August 14/28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Unlike women undergoing menopause, middle-aged men generally do not experience a dramatic decrease in the production of sex hormones, according to background information in the article. Testosterone levels gradually decline as a man ages, decreasing approximately 1.5 percent per year after age 30. The effects of low testosterone levels include decreased muscle mass and bone density, insulin resistance, decreased sex drive, less energy, irritability and feelings of depression.
Molly M. Shores, M.D., and colleagues at the VA Puget Sound Health Care System and University of Washington, Seattle, studied the relationship between hormone levels and death in a total of 858 male veterans older than age 40 years. All participants received care in the VA Puget Sound Health Care System and had their testosterone levels checked at least twice between 1994 and 1999, with at least one week and no more than two years elapsing between tests. The men were followed for an average of 4.3 years and a maximum of eight years, through 2002.
About 19 percent (166) of the men had a low testosterone level; 28 percent (240) had an equivocal testosterone level, meaning that their tests revealed an equal number of low and normal levels; and 53 percent (452) had normal testosterone levels. One-fifth (20.1 percent) of the men with normal testosterone levels died during the course of the study, compared with 24.6 percent of men with equivocal levels and 34.9 percent of those with low levels. Men with low testosterone levels had an 88 percent increase in risk of death compared with those who had normal levels. When the researchers considered other variables that may influence risk of death, such as age, other illnesses and body mass index, the association between low testosterone levels and death persisted.
Is the lower testosterone a cause of earlier death? Or is it just another symptom of the same underlying cause? If testosterone is a cause then will testosterone supplementation increase longevity among those whose testosterone is especially low?
Single folks are at higher risk of dying.
Those who have never married have a 58% higher risk of an earlier death, compared with a married reference group, found Robert Kaplan, Ph.D., of the University of California at Los Angeles and Richard Kronick, Ph.D., of UC San Diego.
Strikingly, the 58% never-married penalty was also higher than the 27% combined death rates for those who were separated or divorced and the 39% rate for widowed persons. they reported in the August issue of the Journal of Epidemiology and Community Health.
So if you are hesitating to enter some marriage since you think it has a high chance of failure maybe you ought to plunge in knowing that you are reducing your odds of death. On the other hand, I have a long time married friend who thinks being married makes the passage of time harder to bear.
I bet the never marrieds are less attractive than those who get married on average. Yes, there are some beautiful never-marrieds. But, again, I'm talking on average. Well, good looks are partly a measure of health.
"Having never been married may be associated with more severe isolation because it is associated with greater isolation from children and other family."
Alternatively, it might be that people who have underlying illnesses that threaten their health and shorten their life expectancy are deemed less suitable as marriage material.
Also, many of the never married men in the study died from infectious disease, most likely HIV, note the authors.
I bet a difference in average lifetime stress between the married and non-married is the biggest cause of the difference in life expectancy. Stress accelerates the aging process. Marriage could reduce stress in a number of ways. For example, I wonder if having two incomes reduces the stress of feared potential and actual unemployment.
I wonder how much of this result is due to IQ. Higher intelligence correlates with longer life expectancy and this relationship holds up even up into the genius range of IQ. Why is this relevant to marriage? Half Sigma has used the General Social Survey Wordsum test as a rough proxy for intelligence and found that the dumbest men have the lowest rates of marriage. Though the rate of never married climbs at the highest Wordsum score levels among men.
Some of the benefit from being married (at least for some married people) probably comes from having someone to pester you to see a doctor or eat better or just to assure you that you are not alone and unwanted.
The mind is a terrible thing to waste. The big risk factors for dementia are the same as the big risk factors for heart disease.
A method to predict a middle-aged person's chance of developing dementia has been devised by scientists.
The test calculates risk by assessing factors such as blood pressure level, body mass index and cholesterol levels, along with age and education.
Having any one of these risk factors doubles a person's chance of developing dementia, and having all three increases their chances by six times, said Dr. Miia Kivipelto, an associate professor at the Aging Research Centre in Stockholm, Sweden, and the study's lead author.
The risk of dementia in 20 years for the middle aged can be calculated with 70% accuracy.
By assessing factors such as blood pressure, body fat and cholesterol levels in 1,400 middle-aged Finns in the 1970s and 1980s, scientists were able to predict, with a 70% accuracy rate, the onset of dementia 20 years later.
If you have high blood pressure then take blood pressure loweriing medicine. If you have high cholesterol then take a statin drug (e.g. Crestor or Lipitor). Also get more exercise and eat better food.
Gina Kolata of the New York Times has written a great article surveying the building body of evidence which shows earlier generations got classic diseases of old age sooner and did so due to infections while very young and poorer nutrition. (and I strongly urge you to read the full article)
New research from around the world has begun to reveal a picture of humans today that is so different from what it was in the past that scientists say they are startled. Over the past 100 years, says one researcher, Robert W. Fogel of the University of Chicago, humans in the industrialized world have undergone “a form of evolution that is unique not only to humankind, but unique among the 7,000 or so generations of humans who have ever inhabited the earth.”
We humans alive today are physically way different on average as compared to previous generations.
In previous centuries heart disease, lung disease, and other ailments showed up decades earlier in human lives.
The biggest surprise emerging from the new studies is that many chronic ailments like heart disease, lung disease and arthritis are occurring an average of 10 to 25 years later than they used to. There is also less disability among older people today, according to a federal study that directly measures it. And that is not just because medical treatments like cataract surgery keep people functioning. Human bodies are simply not breaking down the way they did before.
What is most interesting about these results are the suspected causes: events in the womb and while still quite young can set people up for chronic diseases decades later.
The proposed reasons are as unexpected as the changes themselves. Improved medical care is only part of the explanation; studies suggest that the effects seem to have been set in motion by events early in life, even in the womb, that show up in middle and old age.
“What happens before the age of 2 has a permanent, lasting effect on your health, and that includes aging,” said Dr. David J. P. Barker, a professor of medicine at Oregon Health and Science University in Portland and a professor of epidemiology at the University of Southampton in England.
But it is too late for us to go back in time and tell our mothers to avoid people with colds and flus and other infectious diseases. Our bodies are damaged even from before birth. To fix that damage we need gene therapy, stem cells, and the rest of the panoply of coming rejuvenation therapies.
We are taller, heavier, live longer, get sick later. Almost half of 65 year olds can expect to reach 85. I want that percentage to rise much higher.
In 1900, 13 percent of people who were 65 could expect to see 85. Now, nearly half of 65-year-olds can expect to live that long.
People even look different today. American men, for example, are nearly 3 inches taller than they were 100 years ago and about 50 pounds heavier.
One factor that is different today is that we get infected less and suffer from infections for shorter periods of time. Improved hygiene (e.g. refrigerators and a variety of methods of killing and avoiding food borne pathogens), vaccines, antibiotics, better nutrition, and less exposure to extremes of weather all reduce our rates of infectious disease.
Even if one does not die while infected the infectious diseases take their toll and accelerate aging in a number of ways. First off, the pathogens directly do damage to the body. Second, the immune system's response does damage. In the process of attacking pathogens the immune response causes collateral damage to human tissue. Chemical compounds released by immune cells do damage to our own cells. Third, infection reduces our ability to stay nourished due to decreased appetite, diarrhea, decreased ability to do activities that bring in food, and other mechanisms. Therefore a reduction in infectious disease exposure has reduced the rate at which our bodies accumulate damage.
Conventional wisdom has it that people live longer today because when they do get sick medical treatments can keep them alive. But Dr. Fogel's study of US Civil War veteran medical records shows that back then people got serious illnesses at much younger ages, decades sooner. They lived with these illnesses for much of their lives.
Instead of inferring health from causes of death on death certificates, Dr. Fogel and his colleagues looked at health throughout life. They used the daily military history of each regiment in which each veteran served, which showed who was sick and for how long; census manuscripts; public health records; pension records; doctors’ certificates showing the results of periodic examinations of the pensioners; and death certificates.
They discovered that almost everyone of the Civil War generation was plagued by life-sapping illnesses, suffering for decades. And these were not some unusual subset of American men — 65 percent of the male population ages 18 to 25 signed up to serve in the Union Army. “They presumably thought they were fit enough to serve,” Dr. Fogel said.
Suddenly travel to the past in a time machine has gotten a lot less attractive. Even if one could go back with even more vaccines than we have today the environment back then would take a heavy toll. Though if you could go back and get rich and choose a less severe environment you could buffer yourself from some of the ravages of previous eras.
Note that people living back in the 1800s ate what today would be considered a much more natural diet. No pesticides. No trans fatty acids on french fries. But they had a much higher incidence of heart disease.
Eighty percent had heart disease by the time they were 60, compared with less than 50 percent today. By ages 65 to 74, 55 percent of the Union Army veterans had back problems. The comparable figure today is 35 percent.
That higher rate of heart disease could at least in part be due to chronic infections.
Economist Douglas V. Almond at Columbia University examined health records of children born around the time of the great killer 1918 influenza pandemic and found that women were pregnant during the pandemic gave birth to children who fared much worse by several measures as compared to children born right before or after the pandemic.
To his astonishment, Dr. Almond found that the children of women who were pregnant during the influenza epidemic had more illness, especially diabetes, for which the incidence was 20 percent higher by age 61. They also got less education — they were 15 percent less likely to graduate from high school. The men’s incomes were 5 percent to 7 percent lower, and the families were more likely to receive public assistance.
The effects, Dr. Almond said, occurred in whites and nonwhites, in rich and poor, in men and women. He convinced himself, he said, that there was something to the Barker hypothesis.
Pet peeve: I think employers should organize workplaces to reduce the incidence of diseases transmission at work. Discourage sick people from working. I hate hearing people coughing over the cubicle walls and then seeing other people getting sick. Not only does this cost economically but it is probably also shortening our lifespans. Workplace doors, bathrooms, kitchens, and other locations could be reworked to reduce touching of common surfaces.
You wash your hands in the lavatory sink but have to turn the turn the faucet handle to turn off the water (how about foot pedals?) and then turn a door handle to get out of the ro
