Unemployment reached 23 percent and the GDP shrank by as much as 14 percent, so it's hard to imagine a silver lining to the tumultuous years of the Great Depression. But could the general health of the U.S. population actually have improved when the nation's economic fitness took multiple nosedives? And, if a floundering economy improves longevity, what does this say about our current recession?
It turns out that the bleakest years of the Great Depression, as gauged by GDP and unemployment rate, saw the greatest gains in life expectancy and drops in mortality rates. And during the years that the economy perked up, the nation paid the price in terms of health, according to a study published last week in the Proceedings of the National Academy of Sciences.
To look at the relationship between economic and population well-being, social scientists José Tapia Granados and Ana Diez-Roux of the University of Michigan at Ann Arbor amassed U.S. Census Bureau data on mortality rates, life expectancy, unemployment and GDP for each year from 1920 to 1940. "What this [study] does is to look in detail at data that have now been available for some years but have not been looked at in detail," Tapia says.
First the authors compared the annual changes in life expectancy and mortality rate to annual changes in the unemployment rate and GDP growth for the 20-year period. When they plotted life expectancy over these years on a graph with the economic indicators, a negative correlation between life expectancy and economic growth became obvious. The greatest gains in years of life expectancy coincided with the years of economic recession, 1921 and 1938, and depression, from 1929 to 1933, whereas there were actually longevity setbacks in prosperous years, such as 1926 and 1936.
Similarly, there was a positive correlation between mortality rates and economic upturn. When the variables of age and sex were taken into account, the authors saw the same trend to varying degrees. Although mortality rates dropped or hit a plateau in recessionary years and climbed in years of economic recovery for all groups, the changes in life span were more pronounced for males, people of middle to old age and infants under one.
A trend that endures
"What they're finding for the Depression is what a number of us have found for mild recessions in recent years," says Christopher Ruhm, a professor of economics at the University of North Carolina at Greensboro's Bryan School of Business and Economics, who has studied the health impacts of recessions occurring in the past 50 years. "I don't know if I would have expected the results to hold for the Great Depression, but given that it did, it's not surprising."
This inverse relationship may seem counterintuitive because a strong economy suggests that more people would have access to health care. But, as Tapia points out, "people who have studied the effect of health care on population health are in general not inclined to think that health care has a big impact." Instead, the lifestyles and stresses that accompany a bullish market march up the death rates.
When they have incomes allowing them to indulge, "people tend to drink more, [and] tend to be overweight and obese during periods of economic expansion," Tapia says. In addition, the jobs in the Depression era caused stress, demanding long hours with little vacation and, in some cases, were inherently hazardous.
In keeping with these potential health risks, Tapia's study found that deaths due to cardiovascular disease, which was the major killer in the 1920s and '30s just as it is today, peaked with national affluence. Not surprisingly, the number of injuries related to automobiles, a luxury many people did without during the Depression, also swelled in the years of economic recovery. The authors did not examine the deaths due to dangerous work conditions, but Tapia says earlier studies have found workplace injuries also increased during high employment but, compared with heart attacks, they were a relatively minor cause of mortality, overall.