Intelligent children may be less likely to develop serious disease in adulthood than their less intelligent peers, suggests a long term study in the Journal of Epidemiology and Community Health.
The findings are based on 633 people living in Providence, Rhode Island, USA. All were aged between 30 and 39 at the time of the study, and were part of a larger study monitoring 50,000 pregnancies from birth up to the age of 7 years in 12 cities across the USA.
When they were 7 years old, they took a comprehensive IQ test. During their 30s, they were asked if they had any serious illness, including heart disease, diabetes, cancer, asthma, arthritis, stroke, bleeding ulcer, tuberculosis, and hepatitis.
Factors such as low birthweight (below 2500g), which can affect intellectual development, as well as social and economic factors in childhood, were taken into consideration so as not to unduly influence the results.
Overall the prevalence of serious disease was low, but higher intelligence scores at the age of 7 were associated with lower overall risk of serious disease, even when adjusted for influential factors. People with lower IQ scores in childhood were also more likely to report several illnesses.
The pattern appeared to be general and not restricted to any particular disease. Every extra 15 points on intelligence score at the age of 7 cut the chance of illness as an adult by a third, the findings showed.
Although the chances of having an illness as an adult were higher among those in unskilled or semi skilled jobs, and among those who had fewer years of education, the effect of childhood intelligence still remained significant.
The authors speculate that intelligence may reduce the likelihood of risky and unhealthy behaviours, improve the ability to navigate healthcare systems, and enhance the sense of personal control, thereby minimising the stress response and consequent wear and tear on the body.
And they conclude that general childhood intelligence may be an important and informative early determinant of subsequent adult health.
Click here to view the paper in full: http://press.psprings.co.uk/jech/august/674_ch16444.pdf