Future Health: new research shows the dice are rolled before ten years of age

Although socio-economic status is known to influence health, evidence of the association between economic vulnerability in childhood and the health of older adults is incomplete.

Now, as part of the National Centre of Competence in Research - NCCR Lives project, funded by the Swiss National Science Foundation, researchers at the University of Geneva, have examined data from more than 24,000 people aged 50 to 96 living in 14 European countries.

They found that those who were socio-economically disadvantaged in childhood are at greater risk of low muscle strength at an older age, an indicator they say is indicative of overall health status.

Moreover, this risk was not offset by an improvement in socio-economic status as adults, proving the first years of life are indeed critical.

The researchers suggest the reason for this is a physiological deregulation caused by chronic stress in childhood, which undermines the body’s ability to maintain good health along time.

Linking social inequality and health outcomes

Boris Cheval and Stéphane Cullati, researchers at the NCCR LIVES and the University of Geneva’s faculty of medicine, the tried to uncover how do social inequalities express themselves in terms of objectively measurable health outcomes, over a very long time.

To do so, they analysed nearly 100,000 data from the Survey of Health, Ageing and Retirement in Europe, a 12-year population survey conducted by the EU studying the economic, social and health status of older people.

In total 24,179 participants, half of men and half women, were included in the analysis. The grip strength of participants – as a proxy of overall health status - was assessed with portable dynamometer and compared to a measure of four socio-economic indicators of participants at age ten.

The indicators were: the occupation of the primary breadwinner; the number of books at home, which is a surprisingly reliable indicator of children’s future health; the quality of housing; and the number of people per room.

“The results showed that people who faced poor socio-economic circumstances in childhood had on average less muscular strength than those who were better off in their early years,” said Boris Cheval. “Even when adjusted to take into account socioeconomic factors and health behaviours (physical activity, tobacco, alcohol, nutrition) in adulthood, associations remained very significant, especially among women, who were often less susceptible to benefit from social mobility.”

From social life to biology

Social epidemiology studies often point to the indirect effects of social determinants of health. A number of behaviours, for example, vary by socio-economic status. “Beyond that, our study suggests a direct, biological and lasting effect of a poor start in life,” says Cheval.

There are a number of studies showing that the physiological response to stress develops in childhood. Early and lasting stress can therefore alter response to stress, affecting in particular the functioning of the immune and inflammatory systems, and the general health status.

Similarly, the level of household income in adulthood strongly correlates with objective muscle strength. “A growing body of scientific evidence indicates that the social is incarnated in the body, and thus shows the urgency, when it comes to health, to consider individuals under all of their life circumstances, said Cullati.

In addition, the results show a notable difference between countries. “Scandinavians are generally in better health, regardless of their socio-economic level. They also live in the most egalitarian countries in terms of access to health care and education.” Cullati said.

Age and Ageing: http://dx.doi.org/10.1093/ageing/afy003