September 29, 2009
1930s Economic Depression Boosted Life Expectancy
Good news for Peak Oil doomsters: The Great Depression was accompanied by a rapid rise in life expectancies. So when oil production starts declining every year and most of us lose our jobs we'll live longer?
ANN ARBOR, Mich.—The Great Depression had a silver lining: During that hard time, U.S. life expectancy actually increased by 6.2 years, according to a University of Michigan study published in the current issue of the Proceedings of the National Academy of Sciences.
Life expectancy rose from 57.1 in 1929 to 63.3 years in 1932, according to the analysis by U-M researchers José A. Tapia Granados and Ana Diez Roux. The increase occurred for both men and women, and for whites and non-whites.
"The finding is strong and counterintuitive," said Tapia Granados, the lead author of the study and a researcher at the U-M Institute for Social Research (ISR). "Most people assume that periods of high unemployment are harmful to health."
Whereas mortality declined during economic expansions.
For the study, researchers used historical life expectancy and mortality data to examine associations between economic growth and population health for 1920 to 1940. They found that while population health generally improved during the four years of the Great Depression and during recessions in 1921 and 1938, mortality increased and life expectancy declined during periods of strong economic expansion, such as 1923, 1926, 1929, and 1936-1937.
We are presented such images of poverty back in the Great Depression. From a distance one might expect unemployed people to have starved to death. But hard to square that with a rise in life expectancies. Okay, why this result?
"Working conditions are very different during expansions and recessions," Tapia Granados said. "During expansions, firms are very busy, and they typically demand a lot of effort from employees, who are required to work a lot of overtime, and to work at a fast pace. This can create stress, which is associated with more drinking and smoking.
"Also, new workers may be hired who are inexperienced, so injuries are likely to be more common. And people who are working a lot may also sleep less which is known to have implications for health. Other health-related behaviors such as diet may also change for the worse during expansions."
In recessions, Tapia Granados noted, there is less work to do, so employees can work at a slower pace. There is more time to sleep, and because people have less money, they are less likely to spend as much on alcohol and tobacco.
In addition, economic expansions are also associated with increases in atmospheric pollution which has well-documented short-term effects on cardiovascular and respiratory mortality. Other reasons that periods of economic expansion may be bad for health could include increases in social isolation and decreases in social support that typically occur when people are working more.
What I wonder: Has this pattern held up in recent years?
Workplaces have become a lot safer since the 1920s. Also, hours worked are shorter now than back then. So people working longer hours during an upturn now are probably still working less than, say, workers in the 1920s. Also, economic upturns are less associated with pollution (at least in the United States, though obviously not in China) than was the case in the 1920s and 1930s. So has economic growth become relatively safer today?
The explanation is likely to be much simpler than all of the above.
It's well known that calorie restriction increases longevity (and suppresses fertility) - probably to allow people to get through famines exactly like this, and reproduce later.
When food returns, fertility rises, and longevity falls - what are called diseases of affluence.
A little off topic, the study is about mortality not health, but the experiences with prisoners of war also apply.
A number of studies were done with WW2 POWs. Low calories were spotted then as one key to improved health. But I don't recall any adjustments for smoking. Obviously some prisoners could not get tobacco for years while others would have had at least a moderate supply.
As a group POWs were healthier twenty and thirty years later when compared to soldiers not taken prisoner. Of course that had to exclude situations were there was little or no pretense of decent treatment. The prisoners of the Japanese suffered greatly. And overall there is no doubt the western allies could spare more resources to adequately feed and house prisoners.
Oddly enough I saw a study made about 1962? that said Russian soldiers held prisoner by the Germans were fitter than those never taken prisoner. Who would have guessed considering those foes?
Sorry I can't give references, I haven't followed the topic in several decades. And I don't recommend capture as a health regimen.
I wonder if any of this effect might have been related to the use of new sulfa drugs in the 1930's. Sulfa drugs became widely available in the 1930's and were credited with saving many lives, including FDR's son.
Hate to say this Nick G, but you are completely wrong. It is most likely because you have a misunderstanding of what the term life expectancy means. It is a demographic term that has a specific statistical meaning.
First estimate the number of people and their ages
Second they estimate the number of people who died and their ages
Third they calculate an age specific mortality rate (for every age)
(for example What was the likely hood of 11-12 year olds dyeing in 1929 = # deaths of 11-12 / total # of 11-12 year olds)
You end up with a Death Curve,
the probability of death going up on the Y axis,
and age going across the X axis.
The shape of the Death Curve at that time would have been like a check mark --
high at very young ages - rapidly going down - then slowly going back up.
From this set of age specific mortality rates a "life expectancy" is calculated. (I think it is a poor term that often confuses people, it turns a curve into a point. ) So the researchers needed to show how the curve of age specific death probabilities changed from year to year and then tell why they changed. Your calorie restriction idea does not fit the data.
Yeah, right, another piece of leftist pseudoscience, to convince everybody that poverty in equality is Good For Us.
Of course, longer life has absolutely nothing to do with progress in medicine.
I do recommend "How To Lie With Statistics" to everybody... it's way too easy to "prove" anything with less-than-scurpulous use of statistics.
You have a bit of a point: life expectancy can be affected by changes in mortality at any age, so the researchers do need to show where mortality declined.
Overall, though, I think you're mistaken. I believe the researchers are saying that adult mortality declined - this is consistent with what I said about calorie restriction.
I doubt the researchers had any such political intent.
In the long run affluence makes life extension possible because a growing economy that is generating new tech is generating tech that'll be useful for extending life. The more people are freed up from working on the farm the more that can do science and engineering. The science and engineering leads to ways to develop new drugs and treatments.
I think the detected effects happened too quickly to be the result of calorie restriction. I would expect calorie restriction to slow the aging rate and decrease odds of death only after a much longer amount of time.
I would not be surprised. There are so many reasons why that would be, but the best way to demonstrate to yourself is real easy: go to vacation in Israel the day before Yom Kippur. When the holiday arrives and all driving halts, your lungs will tell you the rest.
I saw a fruit fly study that showed that the effect of calorie restriction was almost instantaneous. Apparently the body becomes "hardier" very quickly, due to the change in signals. Granted, fruit flies only live about a month, but I got the sense that humans might see the difference in a matter of weeks.
For instance, I have the impression that women who starve themselves stop their monthly cycle very quickly (certainly in much less than a year). This study looked at changes over years.
Kind've makes sense: a period of starvation might only last a few weeks - a bodily mechanism designed to get us through such periods should kick in very quickly.