Having a higher IQ during childhood is associated with a greater likelihood of staying disease free and living longer, according to research published in The BMJ.
The finding comes from the largest study yet to examine this association. Researchers from Edinburgh University, Oxford University and University College London followed more than 65,000 individuals (33,536 men and 32,229 women) who completed The Scottish Mental Survey in 1947 at age 11 and who could be linked to cause of death data up until December 2015 (when they would be 79 years old).
After adjusting for confounding variables including age, gender and socioeconomic status, the team found that a higher childhood IQ was associated with a lower risk of dying by the age of 79.
Every additional 15 IQ points was associated with a 28% lower risk of death due to respiratory disease, a 25% lower risk due to coronary heart disease and 24% lower risk due to stroke. The risk of death from injury, digestive disease and dementia was also lowered.
The risk of death from lung cancer and bowel cancer (smoking-related cancers) was also reduced, by 19% and 25%, respectively, whereas no significant link was found between childhood IQ and death from cancers that are not smoking related.
Lead author Ian Deary (Edinburgh University) and colleagues say that people with higher IQs are more likely to be health conscious; they are less likely to smoke and more likely to exercise and seek medical attention when they become ill. The authors suggest that tobacco smoking and its distribution along the socioeconomic spectrum may be of particular importance.
"It remains to be seen if this is the full story or if IQ signals something deeper, and possibly genetic, in its relation to longevity," write Deary and team.
Some experts think that IQ scores should be used in combination with family history factors to assess people’s risk of developing an illness and dying early.
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