Better health and wealth often go hand in hand, and IQ scores may partly explain the pattern, a new study shows.

IQ scores partly explain health gaps between richer and poorer people, write Scottish researchers in BMJ Online First.

Participants were 1,300 people in western Scotland. They took an IQ test in 1987, when they were 56 years old. Their health was then tracked for about 16 years by researchers including the University of Glasgow’s G. David Batty, PhD.

As expected, the most disadvantaged participants were the most likely to die or develop a long-term illness, such as heart disease. Adjusting for participants’ IQ scores tempered but didn’t totally erase that risk.

Healthy, Wealthy, and Wise?

Of course, money and intelligence aren’t joined at the hip. There are plenty of people whose brain power is totally unmatched (for better or worse) with their financial wealth. Naturally, people of any income bracket can also fall ill or thrive.

”Our findings indicate that measured IQ does not completely account for observed socioeconomic inequalities in health but, probably through a variety of processes, may contribute to them,” write the University of Glasgow’s G. David Batty, PhD, and colleagues.

Written IQ tests have been criticized for having cultural biases. So Batty’s team also checked participants’ reaction times in a computer test. Reaction times are a fairly good match for IQ scores, the researchers argue.

Providing educational opportunities early in life may help bridge those health gaps, the researchers note. “Such childhood interventions may also elicit improvements in IQ, although results are mixed."

Few studies have been done on IQ and health inequalities; Batty’s team calls for that to change.

Future research shouldn’t just gather data; it should see “how the links between low socioeconomic status, low IQ, and poor health might be broken,” the researchers write.

By Miranda Hitti, reviewed by Louise Chang, MD

SOURCES: Batty, G. BMJ Online First, Feb. 2, 2006. News release, BMJ.