What the research does is connected a higher intelligence quotient (IQ) in childhood with a lower lifetime risk from the world’s major causes of death, such as heart disease, stroke, smoking related cancers, respiratory disease and dementia. The research build upon earlier studies which show individuals with higher IQs typically tend to live a little longer than those with lower IQs, based on studies of people in middle adulthood. Where the new research, from University of Edinburgh, differs is that it looks at IQ established during childhood.
For the research, the scientists examined the association between intelligence test scores measured at age 11 and leading causes of death in men and women up to age 79. This took the form of a long-term review of medical records relating to 33,536 men and 32,229 women born in Scotland in 1936. These people took some form of IQ test at the age 11. Data relating to causes of death went up to December 2015.
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From this analysis the researchers concluded that higher childhood intelligence is associated with a lower risk of death until age 79:
A higher test score was associated with a 28 percent reduced risk of death from respiratory disease,;
A higher test score was linked with a 25 percent reduced risk of death from coronary heart disease;
Higher scores correlated to a 24 percent reduced risk of death from stroke.
Similar associations were seen with smoking related cancers, digestive disease, and dementia.
Where the research will be challenged is over the concept of IQ itself. At base level IQ is a number representing a person’s reasoning ability (measured using problem-solving tests) as compared to the statistical norm or average for their age, taken as 100. Environmental and genetic factors are thought to play a role in determining IQ; however, the relationship between the two has long been the subject of debate. To add to the uncertainty about how IQ develops, there are many psychiatrists who dispute the concept itself. This is based on the premise there is not a single measure such as IQ which captures all the intelligence that you see in people.
Others, like Stephen Hawking argue that tests to measure IQ are meaningless, for it is what people do, produce and think outwardly that matters. When asked “what is your IQ?”, Professor Hawking replied: “I have no idea. People who boast about their I.Q. are losers.”
The new research is published in the British Medical Journal under the title “Higher IQ in childhood is linked to a longer life.”
