There are plenty of ways to insult someone who is dumb, and now we can add injury to insult – people of lower intelligence die younger. And we have the science to prove it.
The British Medical Journal reported this week on a study of nearly 65,000 Scots tracked from their birth in 1936 to their Scottish Mental Survey at age 11 and all the way through 2015. For every additional 15 points on the intelligence test, a person had a 20% lower risk of death overall. The risk advantage varied for specific diseases; for example, it was 28% lower risk for respiratory disease but only 4% lower for cancers not related to smoking.
It’s a fantastic study because it followed a large number of people for a very long time; by the end of the study, almost half of them had died. That’s a lot of data and a lot of “complete” records.
Survival of the Smartest?
It certainly begs the question whether we could smarten up our children and thereby lengthen their lives. And to some extent, this would work because an environment that prizes education has other factors that help a child’s health. Conversely, environments that do not prize education are likely to have health hazardous factors – a tendency to poorer quality food, tobacco use, etc.
In other words, it’s not the higher IQ by itself that leads to a longer life. It’s all of the ingredients that allowed the child to bloom on the intelligence test.
The study found a dose-response relationship for certain illnesses; that is, the higher the intelligence score, the lower the death risk for cardiovascular disease, coronary heart disease, stroke, smoking-related cancer, and respiratory disease. This is not surprising since lower social-economic status people are more likely to smoke, and, for a variety of reasons, to score lower on these kinds of intelligence tests.
If we improved the social-economic environment, some of these health differences would fade but they would never entirely disappear. These differences were shown in a socialist country where the span of high- to low-status is not as wide as it is in the U.S. Bridging the social divide in the U.S. is considered unpatriotic, even subversive. Still, having such a clear demonstration of the impact of education and social-economic advantage is helpful. It might even show us a new way to strengthen everyone’s health – which would be a smart idea.