Although the cause for the phenomenon is uncertain, economic growth has been positively correlated with higher death rates over the last six decades, a new study has found.

Researchers from the Leyden Academy on Vitality and Ageing, in the Netherlands, studied the economic peaks and valleys, as measured by gross domestic product (GDP) per capita, across 17 countries, from 1950 to 2008. They included in their analysis the deaths among two age groups, 40 to 44 and 70 to 74, which they then crosschecked against economic stability.

The team found that when a country’s economy was booming, death rates increased as well — across both age groups. And when the economy slowed, and tended toward recession, mortality rates declined.

Increases in likelihood were significant. For every one percent GDP per capita increase among 40- to 44-year-old males, mortality rates went up 0.38 percent. For males 70 to 74, the rate increased 0.36 percent. Women saw less prominent an association. Those 40 to 44 years old saw a 0.16 rise in death rates, while those 70 to 74 saw a 0.18 percent uptick.

While the team didn’t outline any specific causes in their report, they offered a number of speculations that may contribute to the observed effect. They also offered possible factors that were likely not involved.

“Traditional explanations as work-stress and traffic accidents cannot explain our findings,” the team wrote. “Lower levels of social support and informal care by the working population during good economic times can play an important role, but this remains to be formally investigated.”

In other words, during periods of economic growth, the working population is larger. People go back to work, rather than spend greater chunks of time caring for their parents. The Centers for Disease Control and Prevention lists the average lifespan as 78.7 years in the U.S., which means the elderly cohort of people examined in the team’s study is likely receiving some sort of care, be it palliative or reparative.

But they’re also not working, so during an economic downturn the means for social support that they would’ve otherwise received is now at work. There may also be less solidarity in times of progress, as people see the need for help as reduced.

While more doctors and physicians are in the hospital during periods of growth, many families still elect to stay out of clinical settings. They opt for familial lifelines, which, unfortunately, may be harder to find when family members are gone from 9 a.m. to 5 p.m. each day.

Overall, the researchers concluded their study merits further attention on the subject, especially in the case of the U.S., where an aging baby boomer population is set to inundate the country’s healthcare system in a matter of only a few years.

"In times of economic turmoil and population ageing,” the authors wrote, “further exploration of the effects the economic environment can have on the well-being of older people is of great importance.”

Source: Rolden H, van Bodegom D, van den Hout W, Westendorp R. Old age mortality and macroeconomic cycles. Journal of Epidemiology & Community Health. 2013.