A weighty issue for many adults

Over half of the adults in the United States are overweight or obese and unfortunately, this trend shows no signs of slowing. In fact, obesity is on the rise worldwide. This is cause for concern because being overweight is a risk factor for heart disease, diabetes, some cancers, and mortality. A recent study published in Archives of Internal Medicine highlights the impact of being overweight on the development of common chronic diseases.

Nearly 125,000 healthy men and women who are volunteers in two prospective studies, the Nurses' Health Study and the Health Professionals Follow-up Study, were included in the current study. From 1986 to 1996 the volunteers completed biennial questionnaires about their health and lifestyle, including diet, physical activity, smoking, and diagnoses. If a disease associated with overweight was reported or a participant died, the researchers obtained and reviewed the volunteer's medical records to confirm the condition or cause of death.

More than half of the volunteers were diagnosed with hypertension or high cholesterol after 10 years of follow-up. In addition, 2% of the women and 3% of the men developed diabetes. The risk of developing these three conditions as well as gallstones, heart disease, colon cancer (in women), and stroke (in men) increased with the magnitude of overweight.

Weight increases linked to greater disease risk

Overweight was defined as a body mass index (BMI) of 25 to 29.9, while a BMI greater than 30 was considered obese. Overweight women were more likely than leaner women to develop gallstones (RR, 1.9; 95% CI, 1.7, 2.0), hypertension (RR, 1.7; 95% CI, 1.6, 1.7), high cholesterol (RR 1.1; 95% CI, 1.1, 1.2), and heart disease (RR, 1.4; 95% CI, 1.2, 1.5). The disease patterns among men were similar. The volunteers classified as obese had an even greater likelihood of developing these conditions.

Diabetes was especially influenced by weight. Overweight men and women were more than three times as likely to develop diabetes than leaner volunteers. And, as weight went up, so did diabetes risk. Volunteers with a BMI of 35 or more were approximately 20 times more likely to develop diabetes (RR 17.0; 95% CI, 14.2, 20.5 for women; RR 23.4; 95% CI, 19.4, 33.2 for men) than those volunteers with a BMI between 18.5 and 24.9, the recommended range.

Interestingly, the disease risk varied even among men and women with BMIs considered normal. Those with BMIs of 22.0 to 24.9--within a healthy range--were more likely to have health problems than those who were a bit leaner with BMIs of 18.5 to 21.9.

This study confirms the results of other reports that link overweight with the conditions noted above and others, including osteoarthritis, sleep apnea, respiratory problems, and even death. Given that even small weight gain increased the risk of health problems, these findings support lowering of the overweight cutoff from a BMI of 27 to 25-a recommendation made in the most recent U.S. Dietary Guidelines.

Maintaining weight is easier than losing weight

This study emphasizes the importance of counseling patients who are overweight or obese about weight loss. Additionally, people need to be encouraged to avoid weight gain, which may occur as one grows older and more sedentary. It is difficult to lose weight and keep it off--so the best strategy is to intervene early, before extra pounds start to accumulate.