The link between intelligence and lifespan is genetic, according to new research published in the International Journal of Epidemiology.
Researchers from the London School of Economics found that the more intelligent twin in a pair lives longer, and crucially this finding was more pronounced in non-identical twins. By comparing genetically identical twins with fraternal twins the researchers were able to mitigate for environmental factors.
Rosalind Arden, a research associate at the LSE, cautions that although the link between intelligence and lifespan is measurable, it is small.
‘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. 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.’
The researchers looked at data from twin studies carried out in the US, Sweden and Denmark. In all cases IQ and age of death were recorded. It is the first study to test for a genetic link between lifespan and intelligence. The research establishes the link but fails to explain it, as Arden explains:
‘It could be that people whose genes make them brighter also have genes for a healthy body. Or intelligence and lifespan may both be sensitive to overall mutations, with people with fewer genetic mutations being more intelligent and living longer. We need to continue to test these ideas to understand what processes are in play.’