Wellcome Trust researchers have studied one million Swedish men and have come to the conclusion that there is a strong link between cognitive ability and the risk of death.
Dr. David Batty, a Wellcome Trust research fellow at the MRC Social and Public Health Sciences Unit in Glasgow, says that a lower IQ seemed to be strongly associated with a higher risk of death from causes like accidents, coronary heart disease and suicide.
He said that the study suggests that government initiatives to increase education opportunities may also have health benefits.
For their study, the researchers analyzed data from one million Swedish men conscripted to the army at the age of 18.
Once Batty and his colleagues had determined whether a person had grown up in a safer and more affluent environment, they found that only education had an influence on the relationship between IQ and death.
According to the researchers, the association between IQ and mortality may be partially attributed to the healthier behaviors 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 behaviors that may partly explain their lower mortality risk," the Science Daily quoted Batty as saying.
While past studies have suggested that IQ scores can be improved with preschool education programs and better nourishment, the current research indicates that this may also have previously unforeseen health benefits, and thus validates government efforts to improve living conditions and education.
Batty says that the public may also be benefited by simplifying health information.
"If you believe the association between IQ and mortality is at least partially explained by people with a lower IQ having worse behaviors, which is plausible, then it might be that the messages used to change health behaviors are too complicated," he says.
"Messages about diet, including how much or what type of alcohol is beneficial, aren't simple, and the array of strategies available for quitting smoking are diverse and actually quite complicated. If you clarify the options available to people who want to, say, quit smoking, in the short term that may have an effect," he adds.
Another study co-authored by Batty, using data from more than 4000 US soldiers and followed them for 15 years, also found that same relationship between IQ scores and mortality, as well as a significant association between higher neuroticism and increased mortality risk.