A study of one million Swedish men has revealed a strong link between cognitive ability and the risk of death, suggesting that government initiatives to increase education opportunities may also have health benefits.
Dr David Batty, a Wellcome Trust research fellow at the MRC Social and Public Health Sciences Unit in Glasgow, and colleagues, found that a lower IQ was strongly associated with a higher risk of death from causes such as accidents, coronary heart disease and suicide.
The researchers studied data from one million Swedish men conscripted to the army at the age of 18. After they had taken into account whether a person had grown up in a safer, more affluent environment, they found that only education had an influence on the relationship between IQ and death.
The researchers say the link between IQ and mortality could be partially attributed to the healthier behaviours displayed by those who score higher on IQ tests.
“People with higher IQ test scores tend to be less likely to smoke or drink alcohol heavily, they eat better diets, and they are more physically active. So they have a range of better behaviours that may partly explain their lower mortality risk,” says Dr Batty.
Previous studies have suggested that preschool education programmes and better nourishment can raise IQ scores. The study suggests this may also have previously unforeseen health benefits, further validating government efforts to improve living conditions and education.