Intelligence doesn’t explain health disparities
Although intelligence seems to play some role in a person’s well-being, new research casts doubt on the theory that intelligence explains the health disparities seen between low- and high-income people.
In a study of nearly 6,000 British adults in various civil service jobs, researchers found that a person’s intelligence—as measured by a standard test—was related to certain measures of health. It did not, however, explain the relationship between lower socioeconomic status and poorer health.
Some researchers in a field called social epidemiology have theorized that intelligence is related to both social and economic attainment and health, and may therefore explain the social inequalities in health that are seen in industrialized countries. Just as greater intelligence may help people land a better education or a better job, the idea goes, it may help them take better care of their physical and mental well-being.
However, many question that notion.
“If intelligence explained all social inequalities in health,” said Dr. Archana Singh-Manoux of the National Hospital of Saint-Maurice in France, “then one could say that individuals themselves are to ‘blame’ for their health and the inequity in the social structure does not matter.”
But that is not the case, according to her team’s findings, published in the American Journal of Epidemiology.
Indeed, Singh-Manoux told Reuters Health, “social structure” can affect people’s health in a number of ways—for instance, by limiting their resources or access to healthcare. In addition, people with lower incomes may be more likely to smoke and less likely to have a nutritious diet and regular exercise.
Work conditions can also come into play, Singh-Manoux noted, as jobs with high demands but little room for independence or creativity—a characteristic of many low-income jobs—have been tied to poorer health.
Singh-Manoux and her colleagues based their findings on data from 5,838 London civil servants who were surveyed and underwent medical exams periodically over 11 years. As part of the surveys, participants took a standard test meant to gauge “fluid intelligence”—a person’s natural ability, not dependent on education, to reason and solve problems on the spot.
Overall, participants’ performance on the test was related to certain health measures, independent of factors like education. For example, men and women who scored higher on the test were more likely to rate their health as good compared with those who scored lower. And women who scored higher on fluid intelligence tended to report better physical functioning.
However, intelligence did not explain the strong links between socioeconomic status and health. Household income was related to all of the health measures the researchers considered—including heart disease, physical and mental functioning, general health and participants’ perceptions of their health.
It’s likely, Singh-Manoux said, that intelligence is related to health because smart people tend to make better lifestyle choices.
“However,” she added, “this does not imply that it explains social inequalities in health.”
SOURCE: American Journal of Epidemiology, May 1, 2005.
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