Link between intelligence and longevity is mostly genetic

Aug 4, 2015

Photo courtesy of Sergey Nivens / Fotolia

By the London School of Economics

The tendency of more intelligent people to live longer has been shown, for the first time, to be mainly down to their genes by new research published in the International Journal of Epidemiology today.

By analysing data from twins, researchers found that 95 per cent of the link between intelligence and lifespan is genetic.

They found that, within twin pairs, the brighter twin tends to live longer than the less bright twin and this was much more pronounced in fraternal (non identical) twins than in identical twins.

Studies that compare genetically identical twins with fraternal twins — who only share half of their twin’s DNA — help distinguish the effects of genes from the effects of shared environmental factors such as housing, schooling and childhood nutrition.

Rosalind Arden, a research associate at the London School of Economics and Political Science (LSE), said: “We know that children who score higher in IQ-type tests are prone to living longer. Also, people at the top of an employment hierarchy, such as senior civil servants, tend to be long-lived. But, in both cases, we have not understood why.

“Our research shows that the link between intelligence and longer life is mostly genetic. So, to the extent that being smarter plays a role in doing a top job, the association between top jobs and longer lifespans is more a result of genes than having a big desk.


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7 comments on “Link between intelligence and longevity is mostly genetic

  • “However, it’s important to emphasise that the association between intelligence and lifespan is small. So you can’t, for example, deduce your child’s likely lifespan from how he or she does in their exams this summer.”

    Without numbers , it’s difficult to assess the reliability or validity of the experiment. We need to know the number of fraternal twin pairs assessed in the study and the average age difference at death between the more intelligent and the less intelligent twin -2 years, 5 years, 7 years? A small sample yielding small differences may prove insignificant.

    Fatally, as described, the experiment relies on crude correlation between only two variables rather than really controlling for other relevant variables. Respective scores on intelligence tests compared only with respective longevity may register insignificant correlations rather than causation.

    The fact that both children were raised in the same household in no way implies that both twins lived in the same environment or had similar life experiences. We need to know about differences in lifestyle that may affect health positively or negatively. Was one twin an alcoholic or drug abuser, morbidly obese; did one work in a space pervaded with carcinogens or toxic chemicals? The study must compare, occupations, travel, residential and work locations, family and marital relationships and physical injuries. Crucially we need to know the cause of death for each subject and contributing factors.



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  • I’m sure there are error bars in the paper. I could imagine a number of things that could lead to greater lifespan on the basis of greater intelligence. Greater intelligence should make it easier to succeed in school, and gain well paying jobs for example, this we know correlates strongly with lifespan, so it is hardly surprising. But I agree the article is a bit light on facts (doesn’t mean the study hasn’t taken all this into account though).



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  • “We know that children who score higher in IQ-type tests are prone to living longer. Also, people at the top of an employment hierarchy, such as senior civil servants, tend to be long-lived. But, in both cases, we have not understood why. …Our research shows that the link between intelligence and longer life is mostly genetic. So, to the extent that being smarter plays a role in doing a top job, the association between top jobs and longer lifespans is more a result of genes than having a big desk.”

    This is the substantive theory of the Bell Curve widely attacked for “proving” that whites perform better than blacks on a battery of IQ tests after adjusting for other variables. Conclusion; whites are genetically superior in intelligence to blacks. Few want to touch the third rail issue.

    The uncontroversial focus in the intelligence-longevity experiment is that each pair of fraternal twins compares only two people. Finding enough pairs to make the sample yield significant findings would pose difficulties. Presumably though the article fails to discuss the necessary condition, both twins must die from organic “natural” causes such as chronic heart disease or cancer. Far more diagnostic information must be supplied. A twin who dies of liver failure subsequent to alcoholism at 58 while his sober counterpart lives to be 93 would disqualify the pair from the study because of the skewed outcome caused by the lifestyle pathology of the alcoholic twin. An accidental death would also disqualify the pair from the study. We are forced to imagine that the twins live side by side, metaphorically speaking, living very much the same kind of generally healthy life until each one dies.

    Further unexplained challenges arise from the long-term time frame of the study. Results cannot be tallied until both twins have expired. With most people living between 75 and 85 years, and many into their 90s, the researchers would have to mark the time when the twins took the same reliable battery of IQ tests in their 20s and 30s and then “wait” for some 40 to 50+ years for them to die. By then the IQ data would be obsolete or unreliable for many of the pairs. By then small differences might be measuring other variables than performance on IQ tests taken in isolation decades earlier.



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