Study bolsters evidence you can't be overweight and healthy

CHICAGO -- Middle-age people who are overweight but have normal blood pressure and cholesterol levels are kidding themselves if they think their health is fine, according to a new study.

Northwestern University researchers tracked 17,643 patients for three decades and found that being overweight in midlife substantially increased the risk of dying of heart disease later in life -- even in people who began the study with healthy blood pressure and cholesterol levels.

High blood pressure and cholesterol are strong risk factors for heart disease. Both are common in people who are overweight, and often are thought to explain why overweight people are more prone to heart disease.

But there is a growing body of science suggesting that excess weight alone is an independent risk factor for heart attacks, strokes, and diabetes.

The new study fits with that evolving school of thought and contrasts with a controversial government study published last year that suggested excess weight might not be as deadly as previously thought.

''The take-home message would be pay more attention to your weight even if you don't have an unhealthy risk-factor profile yet," said lead author Lijing Yan, a researcher at Northwestern and Peking University.

The study appears in today's Journal of the American Medical Association.

Participants were Chicago-area men and women in their mid-40s on average who did not have heart disease or diabetes when the study began. They were followed for an average of 32 years. The researchers tracked deaths from cardiovascular disease and diabetes and hospitalizations for those conditions, starting at age 65.

There were 1,594 heart disease deaths, 31 of them in people who started the study with normal blood pressure and cholesterol.

Among the participants with normal blood pressure and cholesterol levels at the start, those who were obese were 43 percent more likely than normal-weight participants to die of heart disease later on. They also were four times as likely to be hospitalized for heart disease.

Participants who were modestly overweight but had normal blood pressure and cholesterol levels still ran a higher risk than the participants who were at a normal weight.

There were 1,187 participants -- 494 of them overweight or obese -- who had normal blood pressure (120 over 80 or lower) and cholesterol levels (under 200) at the outset. Standard body mass index categories were used to define weight -- results of 25 to 29 were considered overweight, and 30 and above were obese.

Yan said it is possible some participants developed high blood pressure and cholesterol problems during the study, which could have contributed to their deaths.