ATLANTA (CBS Atlanta) — The reason why intelligent people tend to live longer is primarily due to an individual’s genes, according to new research.
Researchers found that about 95 percent of the link between intelligence and longevity can be explained by genetic influences on both traits, as reported by LiveScience. The sample study evaluated participants who took intelligence tests during middle age, so it’s possible some of the findings were skewed by cognitive decline of aging.
However, researchers say the new study indicates that intelligent people don’t necessarily live longer because of healthy lifestyle choices or access to better amenities, but that their genetic makeup builds toward a bright and long life.
“We found that the small relationship between intelligence and life span was almost all genetic,” study researcher Rosalind Arden, a research associate at the London School of Economics and Political Science, told LiveScience.
Several studies have suggested people with higher IQ scores live longer. Previously, researchers attributed this link to people making better choices, having safer jobs or having family advantages. But Arden began to wonder if intelligent people simply have better genes that lead to both higher intelligence and longer life spans.
To test this theory, the team of researchers studied identical and fraternal twins. If longevity is environmental, the smarter of the identical twins would likely live longer due to better lifestyle choices and external factors. However, if longevity is genetic, the smarter twin would likely not have any advantage over the identical sibling. For fraternal twins who share only half of their DNA, the brighter twin would likely live longer if genes were the determining factor.
Arden and her colleagues evaluated data involving sets of twins in which at least one twin was already diseased. The three long-running twin studies involved data from over 1,000 sets of twins. Researchers found that the more intelligent twin tended to live longer, regardless of whether the pairs were fraternal or identical. In fraternal twins, there was a much larger difference in how long each twin lived, ultimately indicating that genes are a major driving factor.
Researchers found lifestyle choices only made up 5 percent of the link between intelligence and life span. However, Arden says that ultimately the intelligence-longevity link is a small one, and that eating well and exercising can unarguably lead to a longer life.
“Nothing we found counteracts the good old stuff your grandmother would have told you about how to live well,” Arden added.
Arden and her team hope to expand the study to dogs or mice to eliminate questionable lifestyle choices, such as smoking or alcohol abuse, that can limit studies of human longevity.