It is well known that wealth correlates with greater life expectancy and related measures such as improved health in later life. The question has always been why this is the case. Wealth correlates with a range of other factors such as education, intelligence, and so forth, all of which can be reasonably expected to influence health via lifestyle choices. In the case of intelligence, there is also some evidence to suggest that more intelligent people are also more physically robust, but the mass of evidence of genetics and longevity also suggests that effect size for genetic variation is small in comparison to that for lifestyle choice.
Genetics, lifestyle and environment are all factors that somehow influence when and how we all age. But the financial situation is also important. Now, researchers have found that four or more years with an income below the relative poverty threshold during adult life make a significant difference as to when the body begins to show signs of ageing.
To learn more about the context, the researchers have tested 5500 middle-aged persons, using various ageing markers: physical capability, cognitive function and inflammatory level. The results were then compared with the participants' income throughout the 22 years leading up to the test. An annual income of 60% below the median income is considered relative poverty. In this way, the researchers found that there is a significant correlation between financial challenges and early ageing.
The participants have been through both physical and cognitive tests, each of which is an expression of general strength and function. Among other things, the researchers measured the participants' grip strength, how many times they could get up from and sit on a chair in 30 seconds, and how high they could jump. The cognitive tests have e.g. been tasks of memorising sequences. The results show, among other things, that the financially challenged group, relative to the comparison group, can get up and sit down two times less per 30 seconds, and that their grip strength is reduced by 1.2 kilos.
In addition, the researchers have measured the inflammatory level of the participants - i.e. an inflammatory state that comes from within and is measured in the blood. A high inflammatory level is a sign that the body is in a state of alert and can likewise be used as a marker for illness and ageing. The study shows that the financially challenged also had higher inflammatory levels.