Combining healthy habits adds up

Women who do it all -- eat well, exercise daily, maintain a healthy weight, and never smoke -- are less likely to die from chronic diseases than their peers who don't keep such good habits. That may not be a shock, but the power of combining all four hallmarks of a healthy lifestyle turned out be greater than any one of those factors alone, including not smoking.

Harvard researchers followed 77,782 healthy women who were 34 to 59 years old for 24 years. Over that span, 8,882 women died. An estimated 55 percent of deaths from all causes could have been avoided if the women followed those four healthy behaviors, including 44 percent of cancer deaths and 72 percent of cardiovascular deaths, according to their analysis. The authors, who report their findings in the British Medical Journal, attribute 28 percent of deaths to smoking, 14 percent to being overweight, 17 percent to being physically inactive, and 13 percent to a poor diet.

The researchers reached their risk estimates by comparing women in the low-risk category for each risk factor with all other women.

"I think we all know that smoking has a major impact on health, so we were not surprised that smoking had a major impact on deaths," lead author Rob M. van Dam, assistant professor of medicine at the Harvard School of Public Health, said in an interview. "But it was a surprise that combined with a modest change in diet, physical activity, and a healthy weight, you could have avoided the estimated 55 percent of deaths, so almost double the deaths attributed to smoking."

The researchers also asked the women, who were part of the Brigham and Women's Hospital-based Nurses' Health Study, about alcohol consumption. They attributed 7 percent of deaths to either abstaining from alcohol altogether or to drinking more than the recommended one drink a day or less. Among nonsmokers, 22 percent of deaths were attributed to being overweight.

Smoking has long been the focus of public health efforts because of its role in cancer, type 2 diabetes, and cardiovascular disease. But as smoking rates fall and obesity and sedentary lifestyles become more widespread, attention should also be paid to diet, exercise, and weight, van Dam said.

"Smoking is still a very powerful risk factor and it still needs to be addressed, but those other factors are increasingly important," he said.

Public health efforts helped make it easier for people to quit smoking and harder to find a place to smoke, strategies that might be modified to help people eat healthy food and get regular exercise, he said. It shouldn't be all about losing weight, though.

"Changing dietary quality and beginning regular physical activity has an important effect on health, and on mortality," he said, "even if they don't lose a large number of pounds."