The British Medical Research Council funded a large study on causes of cardiovascular disease that concluded that, after smoking, low IQ is the largest predictor of cardiovascular disease:
The findings, published in the February issue of the European Journal of Cardiovascular Prevention and Rehabilitation, are derived from the West of Scotland Twenty-07 Study, 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; cognitive ability (IQ) was assessed using a standard test of general intelligence…
The investigators note "a number of plausible mechanisms" whereby lower IQ scores could elevate cardiovascular disease risk, notably the application of intelligence to healthy behaviour (such as smoking or exercise) and its correlates (obesity, blood pressure). A further possibility, they add, "is that IQ denotes 'a record' of environmental insults" (eg, illness, sub-optimal nutrition) accumulated throughout life.
(Image: Left ventricular aneurysm, apical four-chamber echocardiography view, Patrick J. Lynch/Wikimedia Commons, Creative Commons Attribution License)