The advantage of being smart is getting bigger when it comes to longevity.
ATLANTA—May 13, 2008—A new study finds a gap in overall death rates between Americans with less than high school education and college graduates increased rapidly from 1993 to 2001. The study, which appears in the May 14 issue of PLoS ONE, says the widening gap was due to significant decreases in mortality from all causes, heart disease, cancer, stroke, and other conditions, in the most educated while death rates among the least educated remained relatively unchanged. The study is the first to examine recent trends in socioeconomic inequalities in mortality from all causes as well as several leading causes of death in the United States using national individual-level socioeconomic measures.
American Cancer Society epidemiologists led by Ahmedin Jemal, Ph.D., working with scientists from the Centers for Disease Control and Prevention’s National Center for Health Statistics (NCHS) used data from the National Vital Statistics System (NVSS) and death certificate information to analyze more than 3.5 million deaths recorded from 1993 to 2001. They found the overall death rate from all causes decreased significantly during the time period among the most educated (≥16 years) men and women, with the largest decrease in black men. In contrast, the all cause death rate actually increased in those with less than a high school education. The annual percent increase was largest among white women with less than 12 years of education (3.2 percent per year), but was also statistically significant (0.7 percent per year) in white women who had completed high school. The authors say the growing gap was caused largely by an unprecedented decrease in the all-cause death rate among the most educated men (totaling 36 percent in black men and 25 percent in white men over the nine-year interval) largely due to decreases in death rates from HIV infection, cancer, and heart disease.
We calculated annual age-standardized death rates from 1993–2001 for 25–64 year old non-Hispanic whites and blacks by level of education for all causes and for the seven most common causes of death using death certificate information from 43 states and Washington, D.C. Regression analysis was used to estimate annual percent change. The inequalities in all cause death rates between Americans with less than high school education and college graduates increased rapidly from 1993 to 2001 due to both significant decreases in mortality from all causes, heart disease, cancer, stroke, and other conditions in the most educated and lack of change or increases among the least educated. For white women, the all cause death rate increased significantly by 3.2 percent per year in the least educated and by 0.7 percent per year in high school graduates. The rate ratio (RR) comparing the least versus most educated increased from 2.9 (95% CI, 2.8–3.1) in 1993 to 4.4 (4.1–4.6) in 2001 among white men, from 2.1 (1.8–2.5) to 3.4 (2.9–3–9) in black men, and from 2.6 (2.4–2.7) to 3.8 (3.6–4.0) in white women.
Why do I make the claim that this result is due more to intelligence than to education? Linda Gottfredson and Ian Deary have demonstrated intelligence is a powerful variable for influencing longevity (PDF format).
ABSTRACT—Large epidemiological studies of almost an entire population in Scotland have found that intelligence (as measured by an IQ-type test) in childhood predicts substantial differences in adult morbidity and mortality, including deaths from cancers and cardiovascular diseases. These relations remain significant after controlling for socioeconomic variables. One possible, partial explanation of these results is that intelligence enhances individuals’ care of their own health because it represents learning, reasoning, and problem-solving skills useful in preventing chronic disease and accidental injury and in adhering to complex treatment regimens.
Also see Gottfredson's paper Intelligence: Is it the epidemiologists' elusive "fundamental cause" of social class inequalities in health? (PDF format).
My guess is that as the amount of useful knowledge available to influence longevity has increased (e.g. results from dietary and lifestyle research and new types of treatments that require patients to do much self-administration of drugs and therapies) the advantage of being smart has been amplified. If you get sick and you are smart you have more clinical trials to investigate, diets to try, and treatments to follow carefully. You are better able to understand why a treatment should benefit you and therefore more motivated to stick with it. Rather than follow the advice of one doctor you can seek out multiple experts, ask tough questions, and compare notes with other smart people chasing better treatments. You are better able to see through self-serving advice of specialists who are trying to boost their income. You are more likely to recognize serious side effects of treatments and challenge the wisdom of continued use of a treatment.
In the much longer run rejuvenation treatment delivery will become so automated and the treatments so incredibly effective that even the dumbest among us will benefit. But in the shorter run having brains and utilizing those brains to make diet, lifestyle, and other choices to maximize health can provide a big edge.
Under the impression that rising crop price are driven mainly by rising demand? Rising costs suggest that crop production won't rise fast in response to higher prices.
"The price of crops drove what farmers did last year," said Chad Hart, an Iowa State University agriculture economist. Now "it's costs, and that's prompting farmers to reevaluate how they allocate their land this year."
The cost of farming an acre of corn, for example, has risen almost 47% over the last year, according to Wells Fargo & Co. estimates, outpacing the 35% increase in the price of corn in the same period.
It's the same with rice. The price on the futures market of U.S.-grown long grain rice -- the type that is in short supply worldwide -- has risen 64% this year to $22.74 per one hundred pounds. (Such a move also pushes up the price of medium grain rice, which makes up most of what is grown in California.) Still, farmers are expected to plant 549,000 acres of California rice this year, up less than 3% from last year, according to the U.S. Department of Agriculture.
The fact that the cost of farming an acre of corn went up faster than the price of corn makes me think that corn's Energy Return On Energy Invested (EROEI) is rather low. How much of that corn inputs cost increase comes from nitrogen fertilizer whose production is very energy intensive or other chemicals whose production is very energy intensive?
That higher cost of production combined with high prices for wheat and soy are combining to restrict corn plantings. In spite of rising demand for corn for both food and ethanol and a huge increase in prices the amount of corn planted in the United States in 2008 will go down.
Farmers are now expected to plant 86 million acres of corn this year, the Department of Agriculture predicted March 31, down 8 percent from last year, which was the highest since World War II.
Soy doesn't need nitrogen fertilizer since soy roots cooperate with bacteria to fix hydrogen to nitrogen to produce ammonia. The USDA March 2008 plantings report shows some signs of the effects of the high cost of ammonia fertilizer with a shift toward soy and away from corn.
The March 31 report says farmers in all but one U.S. state intend to plant more soybeans this year.
An estimated 75 million acres will be dedicated to the crop, an 18 percent jump from 2007. The U.S. is the world's No. 1 soybean producer.
An acre of corn might yield 160 bushels. Each bushel of corn has about 400,000 BTU of energy (less or more depending on whether you use it for heating or eating). So what happens to total produced available human caloric energy when crops shift from corn to soy? Acreage planted in soybeans might yield 30-43 bushels per acre (depending on whether irrigated). We get 60 lbs per bushel of soy and 17,035 BTU per pound. That is about 1 million BTU per bushel which is higher than the 400,000 or so BTU per bushel of corn. But since land produces only a quarter the number of bushels per acre of soybeans as compared to corn the result is less energy produced per acre. Less energy in. Less energy out. The problem for us is that as we gradually lose the ability to use fossil fuels to produce ammonia fertilizer our crop yields will drop.
The cost of nitrogen fertilizers will likely go much higher as fossil fuels costs continue to rise. But what about other types of fertilizer? A Fortune article about Canadian potash mining company Mosaic reveals expansion of potash mines takes many years.
All this begs a key question: Won't rising demand and sky-high prices lead to new fertilizer supply coming online and eventually to lower prices? Over time, it probably will. But the barriers to entry for newcomers are high. The mine shaft in Esterhazy cost $50 million when it was completed in 1962. "To replicate that today would be $500 million--just to put the shaft down," says Prokopanko. "And it's going to take you five years minimum to develop a new mine complex and a mill and all the infrastructure. Total, it would probably cost you $2.5 billion." (Mosaic recently announced mine-expansion plans that will increase its annual potash production from 10 million metric tons to 17 million, a project expected to cost $3.2 billion over 12 years.)
But in the bigger scheme of things $2.5 billion is not a lot of money. Phosphate and potassium production can probably scale up to meet growing demand - albeit with a delay until big capital expenditures bring new production capacity on line. But ammonia's big price run-up is driven by fossil fuels price increases and the relief there is harder to imagine.
What I'd like to know about the long term cost of nitrogen fertilizer: How much higher does nitrogen fertilizer cost need to rise before electricity as a power source for generating nitrogen fertilizer would become cost competitive? That price, whatever it is, represents the longer term ceiling on nitrogen fertilizer prices.
Maumee agribusiness The Andersons Inc. raised its price for diammonium phosphate farm fertilizer by 177 percent in the last 1½ years.
A short ton, which cost $260 in October, 2006, was $721 in February.
“Fertilizer prices continue to soar. It seems like they just keep going up and up and up,” Mr. Durham, the Henry County farmer, said.
As a result, a March 1 survey by the Ag Department’s Ohio office showed state farmers will plant 3.35 million acres of corn this year, a decrease of 13 percent from last year.
Meanwhile, planting of soybeans, which produce their own nitrogen, will be up 8 percent.
Farmers across the country are expected to plant 8 percent fewer acres in corn this year than in 2007, but Pennsylvania farmers will plant 1 percent more corn than last year, according to a crops expert in Penn State's College of Agricultural Sciences.
A recent NCGA white paper reported that natural gas, which supplies hydrogen for the production of ammonia and has historically accounted for 70 percent of the cost of ammonia production, has seen its price quadruple since 1999 -- from $2 to $8 per million BTUs, ballooning its share of the total ammonia production cost to 85 to 90 percent. Since then, 26 ammonia plants have closed and U.S. production capacity has decreased by 40 percent.
The report also accounts how transportation and distribution costs have jumped, driving up the price of nitrogen since the U.S. has turned to global sources. Ocean freight fees rose from 300 percent to 400 percent from January 2003 to 2008, and shipping anhydrous ammonia by rail has almost doubled since January 2005.
Edward Yardeni, made famous for calling the big 1990s bull market in advance, claims the flow of capital into agriculture will cut crop prices.
TORONTO — Market strategist Ed Yardeni, who made a name for himself with accurate calls on the U.S. stock market's bull runs of recent decades, says that soaring food prices won't last because farmers are rushing to plant more crops and agricultural productivity is increasing with new investment.
“There's so much capital now that's going to pour into agriculture that I think food prices are going to come down sharply,” Mr. Yardeni said at a presentation Wednesday morning sponsored by Thomson Reuters Academy.
That only works if costs do not keep pace with prices. Well, our really big question for your consideration: Will farm costs keep pace with rising food demand from industrializing Asia?
If you feel paranoid because you feel you are being watched then your reaction is rational. Though I would advise "Don't worry, be happy".
Zaba Inc.'s ZabaSearch.com turns up public records such as criminal history and birthdates. Spock Networks Inc.'s Spock.com and Wink Technologies Inc.'s Wink.com are "people-search engines" that specialize in digging up personal pages, such as social-networking profiles, buried deep in the Web. Spokeo.com is a search site operated by Spokeo Inc., a startup that lets users see what their friends are doing on other Web sites. Zillow Inc.'s Zillow.com estimates the value of people's homes, while the Huffington Post's Fundrace feature tracks their campaign donations. Jigsaw Data Corp.'s Jigsaw.com, meanwhile, lets people share details with each other from business cards they've collected -- a sort of gray market for Rolodex data.
Check up on the political leanings of your neighbors.
Some sites use the ability to snoop as a selling point. The Huffington Post's Fundrace feature, which allows users to enter their addresses and see a map showing their neighbors' political donations, uses this come-on: "Want to know ... whether that new guy you're seeing is actually a Republican or just dresses like one?"
Got a friend, neighbor, boss, or local political figure whose personal details pique your curiosity? Give these sites a whirl and let us know if you are successful in finding out surprising facts about them.
Rebecca Smith of the Wall Street Journal reports on the thinking of big new nuclear power plant buyers. Nuclear power is seen to cost double to quadruple previous estimates.
A new generation of nuclear power plants is on the drawing boards in the U.S., but the projected cost is causing some sticker shock: $5 billion to $12 billion a plant, double to quadruple earlier rough estimates.
What became of all the efforts to develop newer lower cost designs? Are these cost increases due to the Asian demand for commodities driving up the cost of iron ore, concrete, and other construction materials?
The latest projections follow months of tough negotiations between utility companies and key suppliers, and suggest efforts to control costs are proving elusive. Estimates released in recent weeks by experienced nuclear operators -- NRG Energy Inc., Progress Energy Inc., Exelon Corp., Southern Co. and FPL Group Inc. -- "have blown by our highest estimate" of costs computed just eight months ago, said Jim Hempstead, a senior credit officer at Moody's Investors Service credit-rating agency in New York.
Oil costs a lot. Then coal and natural gas go up in price in response. Optimists think we still have nuclear as another substitute. But its costs have skyrocketed as well. The inflationary pressures seem inescapable. Photovoltaics might be our only hope for cheap future energy. It doesn't do well as a baseline energy source. But PV makers are coming up with innovations that lower costs.
The Congressional Budget Office still hopes for eventual cheaper nukes.
The Congressional Budget Office just finished a rosy-glasses report on nuclear economics. Even while acknowledging that historical costs for nuclear plants always doubled or tripled their initial estimates, the CBO took heart from promises made by manufacturers of next-generation reactors and a single on-time and on-budget project in Japan to project cheaper nuclear construction costs in the future.
Whether nuclear costs can come down depends on why they are high in the first place. Does anyone know where these cost increases come from? Can innovations in speed of construction yield big cost savings?
Back 8 months ago Moody's was already pretty pessimistic on nuclear costs. But they've become even more pessimistic.
While utilities reportedly have priced the cost of a kilowatt of nuclear power at $3,000 to $4,000, Moody's Investors Services said in October that a more realistic price would be $5,000 to $6,000. That puts the cost of a 1,500-megawatt nuclear plant at about $9 billion, according to reports.
Wulf Bernotat, chairman and chief executive of E.ON, the German energy giant that owns Powergen, has told The Times that the cost per plant could be as high as €6 billion (£4.8 billion) - nearly double the Government's latest £2.8 billion estimate.
Still, getting your own national nuclear power plant has become all the rage.
VIENNA -- At least 40 developing countries from the Persian Gulf region to Latin America have recently approached U.N. officials here to signal interest in starting nuclear power programs, a trend that concerned proliferation experts say could provide the building blocks of nuclear arsenals in some of those nations.
On a day when oil hit a new intra-day trading high of $126.40 we also received indications that attempts to boost world oil production continue to hit roadblocks.
Eni, Italy's largest oil company, and partners developing the Kashagan oil field in the Caspian Sea may delay production by as much as two years, the fourth postponement at the 7 billion- to 9 billion-barrel Kazakhstan discovery.
The start of commercial output may not occur until 2012 or 2013, said Dinara Shaimardanova, an aide to Energy Minister Sauat Mynbayev, confirming his remarks earlier in the capital, Astana. Eni in January said the field, which was the world's biggest discovery in three decades, was expected to start in 2011.
The original plan was to get it into production in 2005. Then it slipped to 2008 and then to 2011. Now production on this field, which is projected to peak at 1.5 million barrels per day, looks to come too late to delay Peak Oil. In a way that is a good thing since the late arriving Kashagan oil will slow the rate to production decline as the world comes off peak production.
Indonesia's leaders think they should leave OPEC because Indonesia has become a net oil importer.
While polemics were going on on its plan to increase domestic fuel oil prices prompted by world crude price hikes, the Indonesian government came up this week with an idea to quit the Organization of Petroleum Exporting Countries (OPEC).
The story of Indonesia fits perfectly with the Export Land Model where demand in the exporting countries soars while their production declines. Look at how oil production and consumption have played out in Indonesia.
Other oil producing countries are heading down Indonesia's path. Some of the big oil producing countries sell gasoline internally at far below market prices. Venezuela, Saudi Arabia, Iran, Qatar, Bahrain and a few other countries sell gasoline for less than $1 per gallon. These gasoline prices mean demand surges in those countries and if they only maintain constant production their exports go down. On top of that Asian demand rises. The Western industrialized countries can afford to outbid some of the poorest countries. But Asian demand and oil producer internal demand will take oil away from the West. Hence the rapid run up in oil prices.House Speaker Agung Laksono said Indonesia`s domestic oil prices much depended on the price of world oil. Indonesia`s oil production and consumption were quite unbalanced with a production of 925,000 barrels per day while its consumption reached 1.4 million barrels per day.
He said that 15 years ago, Indonesia`s daily oil production reached 1.4 million barrels while its consumption reached only about 300,000 barrels per day.
The country's oil production fell for a fourth straight month in April, confirming pessimistic forecasts for the year, while exports rose on the back of improved weather.
Industry and Energy Ministry data released Sunday showed that production stood at 9.72 million barrels per day, down from 9.76 million bpd in March and more than 2 percent lower compared with the post-Soviet high of 9.93 million bpd in October.
Russia is one of the more rapidly growing markets for cars. More metal mouths to feed.
Russian oil executives are claiming that lower taxes could turn around oil production. But this is the same message we heard from the US oil industry in the 1970s. It didn't work then. It won't work now.
Oil output in Russia, the world's biggest supplier after Saudi Arabia, has ``peaked'' and may decline in the coming years, said billionaire Viktor Vekselberg, an owner of BP Plc's venture TNK-BP.
Russian companies need tax breaks to spur exploration and development of new fields to revive growth, Vekselberg told an American Chamber of Commerce conference in Moscow today.
Lukoil president Vagit Alekperov tells a similar story. Leave aside the reason they say Russian production will decline and focus on the decline itself. Russia is one more country that has crossed over onto the list of countries on the down slope for oil production.
The sooner you prepare for what is coming the easier your transition will be. Go smaller with your next car purchase. When you buy that car gasoline will sell for much less than gas will cost when you sell it. Think about how else you can get yourself more energy efficient. Think about whether you can move closer to work or switch to a job which is closer to home. Your commute will make a big impact on your living standard. Find lower energy hobbies. Our energy situation will get much worse before it starts to get better.
Update: Fund manager Tim Guinness, chairman of Investec Asset Management, says oil demand destruction in the industrialized countries is getting offset by demand growth in China, India, and the Middle East. He expects oil prices to hit $200 by 2010.
"What is going on is that OECD demand destruction is somewhere between 200,000 to 500,000 barrels per day (bpd) at the moment, while demand growth in the developing world is still over one million bpd," he said.
This will be a recurring pattern in coming years. Oil consumption in industrialized countries has probably peaked. I expect prices to keep going up at least until the whole world goes into a recession.
Writing in the Yale Daily News Divya Subrahmanyam points to high dollar offers for ideal egg donors.
“Ivy League Egg Donor Wanted.”
Sound familiar? From the News to the New Haven Register, this and similar ads for egg donors have appeared in the pages of local newspapers, attempting to lure intelligent Yale women with sums ranging from $5,000 to $100,000.
One Web site, offering $35,000 is looking for a “Genius Asian donor,” and describes the ideal match: “You should have or be working on a university degree from a world-class university, you should have high standardized test scores, and preferably have some outstanding achievements and awards.”
Another, EliteDonors.com seeks a donor who is Caucasian, “very attractive,” “height 5’9” or taller” and “athletic.” The ad claims to offer $100,000 as minimum compensation.
That $100,000 seems like a large sum of money for human eggs today. But suppose that choosing the right egg results in a smarter child with a responsible, calm, and motivated disposition. The boost in life time income could be many times that initial $100,000 investment.
The value from choosing "premium" eggs will soar as plummeting costs of DNA sequencing technologies bring about an explosion of discoveries about genetic variations for controlling intelligence and personality. The ability to choose between eggs based on detailed genetic profile of donors will greatly increase the probability of getting some desired genetic outcome.
The initial genetic screening of potential donors still doesn't control for the randomness of which portion of a person's DNA went into each egg. But that will become a solvable problem. Fertilization of multiple eggs and genetic testing of each embryo is already possible today. Once we know what thousands of genetic variations do to determine IQ, personality, physical attractiveness, and many other attributes screening of multiple embryos will become very desirable. At that point expect to see skyrocketing prices for donor eggs with the most desired attributes.
An Israeli Jewish doctor successfully started a pregnancy in an Arab girl at the age of 16.
The total fertility rate in Israel is currently estimated at 2.77 children born per woman, one of the highest rates in the world. Ronit Haimov-Kochman, a gynaecologist at Hadassah Mount Scopus Medical Center in Jerusalem, recently led a team of doctors that successfully performed in vitro fertilization (IVF) on a 16-year-old girl. The patient, AH, had had extensive medical and surgical fertility treatment since the age of 14. Haimov-Kochman tells Ewen Callaway why she helped a teenager get pregnant – and why other Arab teens are likely to follow.
The Israelis are losing a demographic battle of the womb to the much more fertile Arabs.
This fertility doctor sees respecting the mentality and cultural norms of another group as important drivers in her decision. Personally, I'm not suicidal. Quite the opposite in fact. But I respect the cultural norms that cause this doctor to behave suicidally for her culture (though I'd lose all that respect if my own culture was threatened). On second thought, introspecting I see that I do not feel that respect. Indifference is more like it. Not my country. Not my culture.
So what contributed to your team's eventual decision to treat AH?
Treatment of AH was based on the couple's decision to start therapy. Respecting the patient's mentality and cultural norms, the patient's right for therapy, and its wide availability in Israel all contributed to our decision to treat the patient.
It is understandable that in a society with an exceedingly high fertility rate, where the major role of the female spouse is to bear and rear children, strong peer and family pressure is imposed on infertile patients – especially the young and less educated ones.
What do you all think? Do 14 year old Muslim girls in Jerusalem have a right to begin fertility treatment?
More basically, is there a basic right to reproduction? If so, why? Does it not matter what the consequences are?
The Financial Times reports the Chinese government wants the Chinese to buy lots of farmland in other countries in order to boost production to feed China.
Chinese companies will be encouraged to buy farmland abroad, particularly in Africa and South America, to help guarantee food security under a plan being considered by Beijing.
A proposal drafted by the Ministry of Agriculture would make supporting offshore land acquisition by domestic agricultural companies a central government policy. Beijing already has similar policies to boost offshore investment by state-owned banks, manufacturers and oil companies, but offshore agricultural investment has so far been limited to a few small projects.
Industrialization causes higher demand for food which causes higher food prices which causes a flood of capital to go into agriculture. The result? Less land for animals. More pollution from agriculture.
But this plan only works if the target countries allow export of the increased production.
Argentina has banned beef exports, while Egypt and India have stopped shipments of rice.
Kazakhstan has prohibited wheat exports. Russia has slapped a 40pc export duty on shipments, and Pakistan a 35pc duty.
China, Cambodia, Malaysia, Philipines, Sri Lanka, and Vietnam have all imposed export controls or forms of rationing to ease the crisis.
Instead, Asia is increasingly transforming farmland into office parks and suburbs. In the Philippines, half of irrigated land has been transformed into urban development in the past two decades. While this fuels new economic engines such as services and industry, it also undercuts resources needed to grow food.
...
The population in the Philippines has grown by roughly 2 percent a year since 2000, one of the highest rates in Asia, leading to a corresponding leap in rice consumption. And across Asia, exploding middle classes with more money and bigger appetites are eating more rice – and more meat. Meat production requires huge amounts of water, labor, and grains to feed cattle, which in turn diverts resources away from rice production.
Why have food prices rocketed? Paradoxically, this squeeze on the poorest has come about as a result of the success of globalization in reducing world poverty. As China develops, helped by its massive exports to our markets, millions of Chinese households have started to eat better. Better means not just more food but more meat, the new luxury. But to produce a kilo of meat takes six kilos of grain. Livestock reared for meat to be consumed in Asia are now eating the grain that would previously have been eaten by the African poor. So what is the remedy?
The best solution to a problem is often not closely related to its cause (a proposition that that might be recognized in the climate change debate). China’s long march to prosperity is something to celebrate. The remedy to high food prices is to increase food supply, something that is entirely feasible. The most realistic way to raise global supply is to replicate the Brazilian model of large, technologically sophisticated agro-companies supplying for the world market. To give one remarkable example, the time between harvesting one crop and planting the next, in effect the downtime for land, has been reduced an astounding thirty minutes. There are still many areas of the world that have good land which could be used far more productively if it was properly managed by large companies. For example, almost 90% of Mozambique’s land, an enormous area, is idle.
But to the wild animals in Africa and South America the land doesn't look undeveloped. It looks like where they get their food from.
Asian economic development translates into land development for farming in Africa. The more capital accumulates the more capital available to bring more land into production for human uses. Africa's problems have been an obstacle for Western and East Asian people to develop the place. But given high enough food prices the costs of dealing Africa's problems will become affordable for large farming businesses from outside of Africa. The money Bill Gates is spending to develop treatments for tropical diseases will bring treatments that let farmers work in areas which otherwise offer some protection to wildlife due to disease barriers.
Birth control offers a different way to solve the food problem which will save a lot of land from agricultural development.
Being too skinny also poses a dementia risk?
Being obese can increase the risk of Alzheimer’s Disease by as much as 80 per cent, according to a study in the May issue of Obesity Reviews.
It is harder to tease out harmful effects of low weight as compared to overweight because people who have undiagnosed diseases often lose weight before getting diagnosed. So the population of skinny people include people who are about to get diagnosed with cancer or some other disease. The longer a group gets followed the less that bias influences the results.
But it’s not just weight gain that poses a risk. People who are underweight also have an elevated risk of dementia, unlike people who are normal weight or overweight.
US researchers carried out a detailed review of 10 international studies published since 1995, covering just over 37,000 people, including 2,534 with various forms of dementia. Subjects were aged between 40 and 80 years when the studies started, with follow-up periods ranging from three to 36 years.
The review, which included studies from the USA, France, Finland, Sweden and Japan, also included a sophisticated meta-analysis of seven of the studies, published between 2003 and 2007 with a follow-up period of at least five years.
All kinds of dementia were included, with specific reference to Alzheimer’s Disease and to vascular dementia – where areas of the brain stop functioning because the blood vessels that supply them are damaged by conditions such as high blood pressure or heart disease.
“Our meta-analysis showed that obesity increased the relative risk of dementia, for both sexes, by an average of 42 per cent when compared with normal weight” says Dr Youfa Wang, Associate Professor of International Health and Epidemiology at Johns Hopkins Bloomberg School of Public Health, Baltimore.
“And being underweight increased the risk by 36 per cent.
“But when we looked specifically at Alzheimer’s Disease, the increased risk posed by obesity was 80 per cent. The increased risk for people with vascular dementia was 73 per cent.
The harmful effects of obesity suggest that bariatric surgery ought to be considered by the chronically obese. Here's another reason: bariatric surgery might cure type 2 insulin resistant diabetes.
