I am a geriatrician, a physician who studies those things that get in the way of any of us living all of our fully allotted 100 years. Numerous risk factors have been securely identified. Smoking being the most evident. Gluttony and sloth both shorten life. High risk occupations (miners), inability to cope with stress are also agreed upon life shorteners.
Ian Dreary, director of the University of Edinburgh's Center for Cognitive Aging and Cognitive Epidemiology, says that more important than all of the above demons regarding longevity is intelligence. A remarkable study was conducted in Scotland June 1, 1932 on 87,000 children born on that day who were enlisted. These were enrolled into a longitudinal survey that is on-going 75 years later. Children who scored in the top 50 percent of the cohort for intelligence were more than twice as likely to live into their late 60s than those in the lower half. A 15-point lower IQ score translates to a 20 percent less chance of reaching 76. A 30 percent disadvantage means a 37 percent lower likelihood of reaching 76. Subsequently, many workers have concluded that there is a strong inverse relationship between early life intelligence and mortality.
I recall my interest 25 years ago when I first read about the nun study. Dr. David Snowden is an epidemiologist and professor of neurology then at the University of Minnesota. He had access to 678 members of the School of Sisters of Notre Dame. Nuns are an ideal study cohort because they have a homogeneous lifestyle with no behavioral quirks, a common life pattern, little debauchery, and an altogether virtuous demeanor.
The study was undertaken in 1989 specifically to assess age associated brain health. Snowden exploited the fact that the pre-admission application contained an autobiographical essay written when they were in their 20s. This set of documents was assessed for "verbal density," the richness of the textual effort. These writings were graded according to their complexity, and their grades compared to their late life courses. They all agreed to donate their brains for post-mortem analysis. Once again the IQ/ longevity relationship was obtained.
A study of 1 million Swedish men concurred with the hypothesis.
A study on honey bees supports this view. Honeybees are easily trainable by positive or negative forces so they are a good model for human learning. Gro Amdam of the Norwegian University of Life Sciences designed an experiment that distinguished the fast from the slow learners. When exposed to a toxic environment the smart bees far outlived the slow.
I have long championed the notion that fitness is the best death preventive.
Now to this I add intelligence.
But I also consider the brain to be a muscle. Use it!
1) Dreary, I et al, Outsmarting Mortality Scientific American, July 2011.
2) Snowden, D. Aging with Grace: What the Nun Study Teaches Us About Living Longer, Healthier, and More Meaningful Lives 2001, Bantam