Research Confirms a Link between Intelligence and Life Expectancy
Adam Rifkin stashed this in Longevity!
Higher intelligence means, on average, a longer life.
People are living longer than ever. According to a 2015 World Health Organization report, Japanese live the longest, with an average life expectancy of 84, while Americans can expect to live to 77. At the same time, it is an obvious fact that some people live much longer than other people. There is inequality in mortality.
What explains this inequality? Epidemiological research confirms what intuition suggests: lifestyle matters. A 2012 study published in Preventive Medicine followed over 8,000 people over a 5-year period. Risk of death by any cause was 56% lower for non-smokers, 47% lower for people who exercised, and 26% lower for those who had a healthy diet. Italian researchers analyzed the diets of inhabitants of the Monti Sicani region of Sicily, where there is a remarkably high prevalence of people who live to be 100. Along with being physically active and having close contact with relatives, the centenarians surveyed were found to adhere to a traditional Mediterranean diet.
A more surprising discovery is that there is a strong link between mortality and IQ: higher intelligence means, on average, a longer life. This relationship has been extensively documented by Ian Deary and his colleagues at the University of Edinburgh using data from the Scottish Mental Surveys. In 1932, the Scottish government administered an IQ test to nearly all 11-year old children attending school on a single day. More than sixty years later, focusing on the city of Aberdeen, Deary and colleague Lawrence Whalley set out to identify who from the cohort was still alive, at age 76. The results were striking: a 15-point IQ advantage translated into a 21% greater chance of survival. For example, a person with an IQ of 115 was 21% more likely to be alive at age 76 than a person with an IQ of 100 (the average for the general population).
The link between IQ and mortality has now been replicated in upwards of 20 longitudinal studies from around the world, and has given rise to the field of cognitive epidemiology, which focuses on understanding the relationship between cognitive functioning and health. One major finding from this new field is that socioeconomic factors do not completely explain the IQ-mortality relationship. In one study, focusing on the Central Belt region of Scotland, researchers linked IQ scores for over 900 of the participants from the 1932 study to those participants’ responses on a national health survey conducted in the early 1970s. The researchers found that statistically controlling for economic class and a measure of “deprivation” reflecting unemployment, overcrowding, and other adverse living conditions accounted for only about 30% of the IQ-mortality correlation.
This evidence suggests that genes may contribute to the link between IQ and living a long life. The results of a new study by Rosalind Arden and colleagues in the International Journal of Epidemiology provide the first evidence for this hypothesis. Arden and colleagues identified three twin studies (one from the U.S., one from Denmark, and one from Sweden) in which both IQ and mortality were recorded. (Twin studies disentangle the effects of environmental and genetic factors on an outcome such as intelligence or lifespan by comparing identical twins, who share 100% of their genes, and fraternal twins, who on average share only 50% of their genes.) They then performed statistical analyses to estimate the contribution of genetic factors to the IQ-lifespan relationship. The results were clear and consistent: genes accounted for most of the relationship.
IQ predicts outcomes such as job performance, academic achievement, and, as it happens, mortality, better than any psychological factor that we know of. At the same time, IQ isn’t destiny—it is one factor among many that predict these outcomes. Things like personality, interests, and motivation matter, too.
Top Reddit comment:
That is pretty interesting, plus we all like to think we are smarter than average, so now we all get to think we are going to live longer.
Could the possible link be related to those with a higher intellect making a series of better decisions thought out a lifetime. I.E. Not smoking, moderating alcohol and unhealthy food intake, not trying to jump that jet ski over that SUV..... etc.
Sorry Panda but alcohol intake isn't super correlated with age at death, at least in the US. People who drink a lot when they're young tend to die earlier because their top causes of death are accident, suicide, and homicide which all obviously have a strong correlation to drinking -- but there's a lot fewer of them. But by the time you get to very old people, the ones who drink the most are also the ones who live the longest.
Makes sense to me because by that point the people who were going to succumb to the downsides of drinking have either died or quit, just like they tell you at the AA meetings! Meanwhile the folks who can drink steadily without acting the fool get the considerable health benefits, like cardiovascular blasting and greater social life, of plentiful boozes!
Your logic makes sense to me.
You're right that there's probably a survivor bias, too: if you don't die early, it might make you stronger.