To avoid a heart attack, it's a good idea to lose weight and quit smoking. Perhaps the best cardiac health insurance, however, is going to graduate school.
That is the finding of a new study that followed nearly 4,000 people for three decades. Compared to individuals who had a high-school diploma or less, those whose education went beyond a college degree had blood pressure that was lower by several points, even after risk factors like smoking were taken into account. "Blood pressure is a classic predictor of heart disease," and education appears to have an impact on it, said Eric B. Loucks, an assistant professor of community health at Brown University, the lead investigator. He and two colleagues published their results in the journal BMC Public Health on Sunday.
Though higher social and economic status, including education level, has long been associated with better health, the mechanism behind that link has been vague. Other researchers said that identifying blood-pressure changes helps bring the mechanism into focus. "It's a very interesting finding, and definitely a piece of the puzzle," said Nora Franceschini, an assistant professor of epidemiology at the University of North Carolina at Chapel Hill, who studies risk factors for hypertension.
The drop throughout the group was about 3 points for women and about 2.5 points for men in their systolic pressure, the first number in a blood pressure reading. That is not enough to be clinically significant for any single individual, Mr. Loucks said. "But spread over a population, it can have an important effect, like decreasing overall salt intake a little bit," he noted. (Blood pressure is measured on a scale of millimeters of mercury. Normal systolic pressure is less than 120; a reading of 120 to 139 is considered borderline; and anything above that is high.)
The group analyzed by Mr. Loucks was part of the Framingham Offspring Study, an offshoot of a large research project to identify heart-disease risk factors among residents of the town of Framingham, Mass. The 3,890 individuals, who were all in their 30s when the study began, were followed from 1971 through 2001 and were assessed seven times during that period. In addition to age and gender, the researchers noted people's obesity levels, smoking and drinking habits, whether they were on blood-pressure medication, and their number of years of schooling.
No matter what the age of the individual, the blood-pressure benefit for those who had 17 or more years of education (indicating college and further study) persisted when compared to readings for those who had 12 years or less. There was also a smaller benefit for those with 13 to 16 years of school. "So there appears to be a graded response, and the more education you have, the better you do," Mr. Loucks said.
The benefits for advanced degrees persisted, though at a slightly lower level, when obesity, drinking, and hypertension medication were taken into account, giving the scientists confidence the effects are real.
One limitation of the study is that most residents of Framingham were white in the early 1970s, when the research began, so the results may not apply to other racial or ethnic groups.
Even in Framingham, higher education itself probably did not act on blood pressure. But the people with more-advanced education levels may be better able to resist stress because of enhanced economic and social position, and that is probably part of the explanation, says Donna D. McAlpine, an associate professor of public health at the University of Minnesota-Twin Cities. "My sense is that it's the social factors. Higher social status seems to be a buffer against many sources of stress. And stress affects blood pressure," she said.
Mr. Loucks agreed, and also said stress buffering might explain why the blood-pressure effect was stronger among women. Women with low education levels are more likely to live below the poverty line, and thus to be buffeted by circumstances far more than they are buffered from them.
"Maybe education is a fundamental factor in health that we can intervene on," he said, noting that improving education may be easier than reducing poverty.
Ms. McAlpine echoed his point, saying that "if we could change social and economic status, we would have a huge impact on health. But it's so hard to make a broad impact there." Focusing on education, she said, could make a meaningful difference.