Death rates are higher among middle-aged and older people when the economy is booming, a new study has found.

While many would expect death rates to be higher during times of recession, it appears that this may not always be the case.

According to Dutch scientists, life expectancy in the developed world has continued to rise in recent decades. Economic growth in the long-term is seen as important in maintaining this trend because ‘wealth creates health', they said.

As many countries are currently in recession and the population of older people is increasing, the scientists wanted to assess what impact this could have on life expectancy.

They studied the GDP (gross domestic product) per capita of 19 developed counties worldwide, including Ireland, the UK, France, Spain, Australia, Japan and the US, between 1950 and 2008.

GDP is seen as an indicator of national economic health.

These GDP figures were then plotted against the number of deaths among people aged 40-44 and 70-74 during the same period.

The study found that when an economy was growing, death rates among people in these two age groups actually increased. However, when an economy was heading for recession, the death rates fell.

The scientists suggested a number of reasons why this may be so. For example, increased job stress in a booming economy could have an effect. However, they acknowledged that those in the older age group would probably not be affected by this as they would have already retired.

Road traffic accidents and unhealthy lifestyles also tend to increase if an economy is expanding, however the scientists said these still do not fully explain the trends they found.

They suggested that changes in relation to social support may play a role. Higher employment seen in a booming economy may leave people with less time to care for older relatives, even in an informal way, and this may also lead to increased stress for the carer.

This theory, the scientists said, warrants further research.

Details of these findings are published in the Journal of Epidemiology and Community Health.