Lower IQ Affects Health
Lower IQ raises the risk of heart disease in later life, according to UK research.
It is widely accepted that social background has a strong influence on the risk of dying from strokes and heart attacks (known as cardiovascular events). Much of this effect has been put down to the differences in income, stress, smoking, diet and exercise levels between different socioeconomic groups. This UK study was carried out to discover if any other factors were also at work.
The UK study looked at the lives of more than 4,000 US soldiers, drawn from a wide range of social backgrounds to compare different groups’ risk of dying from heart disease and stroke. The researchers then took into account age, socioeconomic status, and nine known risk factors of heart disease (including blood pressure levels (systolic and diastolic), cholesterol levels (total amount and HDL level), body mass index (BMI), smoking and glucose levels). They found that all these factors combined could not explain all the differences found.
However, when IQ was taken into account, the differences between the groups was lowered, suggesting that IQ is an independent risk factor for death from heart disease and stroke. In fact, the researchers calculate that a lower IQ could account for up to 23% of the difference in risk between the highest and lowest socioeconomic groups.
The researchers suggest three possible reasons for the effect of IQ on heart disease and stroke:
* greater intelligence might lead to greater knowledge about how to pursue healthy behaviours
* intelligence may “cause” socioeconomic position, for example more intelligence leads to more education, income, occupational prestige
* intelligence may be a marker for something else, and it is that something else, early life exposures, for example, that leads to mortality.