Cognitive Epidemiology - Overall Mortality and Morbidity

Overall Mortality and Morbidity

A strong inverse correlation between early life intelligence and mortality has been shown across different populations, in different countries, and in different epochs." Various explanations for these findings have been proposed:

"First, ...intelligence is associated with more education, and thereafter with more professional occupations that might place the person in healthier environments. ...Second, people with higher intelligence might engage in more healthy behaviours. ...Third, mental test scores from early life might act as a record of insults to the brain that have occurred before that date. ...Fourth, mental test scores obtained in youth might be an indicator of a well-put-together system. It is hypothesized that a well-wired body is more able to respond effectively to environmental insults..."

A study of one million Swedish men found showed "a strong link between cognitive ability and the risk of death."

People with higher IQ test scores tend to be less likely to smoke or drink alcohol heavily. They also eat better diets, and they are more physically active. So they have a range of better behaviours that may partly explain their lower mortality risk. —-Dr. David Batty

A similar study of 4,289 former US soldiers showed a similar relationship between IQ and mortality.

The strong correlation between intelligence and mortality has raised questions as to how better public education could delay mortality.

There is a known inverse correlation between socioeconomic position and health. A 2006 study found that controlling for IQ caused a marked reduction in this association.

Research in Scotland has shown that a 15-point lower IQ meant people had a fifth less chance of seeing their 76th birthday, while those with a 30-point disadvantage were 37% less likely than those with a higher IQ to live that long.