A new study shows that the death rate among middle-aged and elderly people is higher when the economy is booming than when it is heading into a recession.

As many countries are not only in recession, but also have increasing numbers of of elderly people in the population, the authors wanted to know what impact this might have on life expectancy.

The researchers, from the Leyden Academy on Vitality and Ageing and Leiden University Medical Center in the Netherlands, defined middle age as years 40-44 and older people as aged 70-74.

They analyzed the gross domestic product (GDP) per capita – an indicator of national economic health – of 19 developed countries in Europe, Scandinavia, North America and Australasia between 1950 and 2008, and they plotted the number of deaths over the same period.

The results, published online in the BMJ’s Journal of Epidemiology and Community Health, reveal that when economies were expanding, death rates increased for both middle-aged and older people, but when economies were heading for recession, the death rates decreased.

On average, for every 1% point increase in GDP, death rates rose by 0.36% among older people, and by 0.38% among the middle-aged.

Women fared slightly better than men, with the effect being marginally smaller, rising by 0.18% among those in their 70s, and by 0.16% among those in their 40s.

Exactly why this is happening remains unclear. But the authors doubt that increased levels of work stress and traffic accidents, which are a result of higher rates of employment, fully explain these trends.

Life expectancy in the developed world continues to rise, largely because of the reduction in old age mortality, say the authors.

Long-term economic growth is an important factor in maintaining this trend, because “wealth creates health,” they add.

The study points out that people who are unemployed during times of recession reduce their alcohol consumption, resulting in fewer road accidents. On the flip side, however, times of high unemployment see the number of people smoking or eating unhealthy diets increase, as well as spikes in the incidence of suicide and homicide.

And, as the researchers acknowledge, unhealthy lifestyles do not take their toll immediately, usually resulting in an increased mortality risk some years later.

The authors speculate about other possible explanations for the figures, including increased job stress – though this would not affect older people – and increased air pollution, which is known to increase when economies are thriving, but which does not explain the gender differences in the figures.

But changes in social support may exert some influence, they suggest, as higher employment could mean less time for informal caregiving to older people and heightened stress among the carers.

The researchers say heightened stress is a factor worth exploring further in view of the lack of evidence to substantiate this theory.

The study concludes:

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