Previous research has shown that lower intelligence scores - as reflected by written or oral tests of IQ - have been associated with a raised risk of cardiovascular disease. Now, a new study funded by Britain's Medical Research Council, which set out to gauge the relative importance of IQ alongside other risk factors, has found that lower intelligence scores were associated with higher rates of cardiovascular disease and total mortality at a greater level of magnitude than found with any other risk factor except smoking.
The findings, published in the February issue of the European Journal of Cardiovascular Prevention and Rehabilitation, are derived from a population study designed to investigate the influence of social factors on health. The present analysis was based on data collected in 1987 in a cohort of 1145 men and women aged around 55 and followed up for 20 years. Data were collected for height, weight, blood pressure, smoking habits, physical activity, education and occupation. Tests for cognitive ability (IQ) were assessed using a standard test of general intelligence.
Scientists took nine major risk factors for cardiovascular mortality and compared them with data from the study participants. Results showed that the most important risk factor was cigarette smoking, but it was followed by low IQ. Similar results were apparent when the health outcome was total mortality.
Commenting on the public health implications of the findings, the study's principal investigator Dr David Batty said that the individual skills reflected in a person's IQ may be important in the management of personal cardiovascular risk.
"From a public health perspective, there is the possibility that IQ can be increased, with some mixed results from trials of early learning and school readiness programs," said Dr Batty.
Personally, I'd suggest that those with a higher IQ have read about factors relating to personal health and have taken action, resulting in a reduced risk factor.