If you possess mighty brain power, you may wind up with more years in your life to mull the meaning of life.
A comprehensive, population-wide study from Scotland that tracked intelligence scores and health patterns of individuals from 1936 to 2015 found an inverse association between mental prowess and mortality rates.
The large-scale study, based on the lives of more than 65,000 people born in Scotland in 1936, discovered that a higher IQ in childhood reduced the risk of death at age 79 from a wide range of diseases and conditions, including heart disease, stroke, some cancers and dementia.
“This research project has taken several years to complete and covers a large dataset across Scotland. We don’t fully know yet why intelligence from childhood and longevity are related, and we are keeping an open mind,” said study author Ian Deary, Director of the Center for Cognitive Aging and Cognitive Epidemiology at the University of Cambridge.
The researchers controlled for several factors, including age, gender and wealth, that might have influenced health results. Yet still, the intelligence-and-longevity link remained. They speculate that a number of different factors may be at play in the results they found.
“Lifestyles – e.g., not smoking – education, health literacy, less deprivation, and genetics might all play a part. Future studies would benefit from measures of the cumulative load of such risk factors over the life course,” added Deary.
A Closer Look
The researchers analyzed IQ scores with causes of death, along with a person’s age of mortality, to come up with their findings. For example, for some causes of death, they compared people in the highest 10 percent of IQ scores to people in the lowest 10 percent. Here are some specific discoveries, as reported in the British Medical Journal.
- “Risk of death related to lifetime respiratory disease was two-thirds lower in the top performing 10th for childhood intelligence versus the bottom 10th.”
- “For deaths from coronary heart disease, stroke, smoking-related cancers, digestive diseases and external causes, risk of mortality was halved for those in the highest versus lowest 10th of intelligence.”
- “The risk of dementia-related mortality and deaths by suicide were reduced by at least a third in the highest performing quarter of intelligence test score versus the lowest quarter. There was no evident association between childhood intelligence and mortality from cancers not related to smoking.”
- “The greatest difference in effect estimate was for dementia, whereby a 1 [standard deviation] higher score in childhood intelligence was associated with a 10% reduced risk of death from dementia in men and a 24% reduced risk in women.”
- “The strongest association was evident for death related to lung cancer: the risk in the highest performing 10th of childhood intelligence was reduced by two-thirds compared with the lowest performing 10th.”
The associations remain strong across gender boundaries and are found in both men and women, the researchers report. They also add that socioeconomic status does not appear to impact the rates of longevity.
Ultimately, “in this first whole population birth cohort study linking childhood intelligence test scores to cause of death, in a follow-up spanning age 11-79, we found inverse associations for all major causes of death,” write the researchers.
Richard Scott is a health care reporter focusing on health policy and public health. Richard keeps tabs on national health trends from his Philadelphia location and is an active member of the Association of Health Care Journalists.