Highly obese women are also 12 times more likely to have knee replacement surgery, and five times more likely to have high blood pressure than women who are at a normal weight, says the study.

Men in the highest weight categories are six times more likely to have a knee replaced or have high blood pressure than are their normal-weight peers, say the researchers.

The study subjects were aged 50 to 76 and lived in western Washington state.

41 Conditions

In all, the researchers correlated obesity with 41 health conditions, including life-threatening conditions like heart failure; some, like high blood pressure, that increase the risk of more serious diseases; and health complaints that reduce the quality of life, like insomnia or chronic fatigue, says lead author Ruth E. Patterson, Ph.D., R.D.

The study appears in the December issue of the American Journal of Preventive Medicine. "No other study has provided data on the association of obesity with such a compendium of health conditions," Patterson says.

Carrying extra weight was tied to 37 of the 41 health conditions studied in women and 29 of 41 conditions in men.

Heart Failure, Chronic Fatigue

In addition to diabetes, knee replacement and high blood pressure, highly obese women were also more likely to have a history of heart failure, gall bladder removal, pulmonary embolism, chronic fatigue and insomnia. However, these women also experienced slightly lower levels of osteoporotic fractures and constipation, Patterson says.

Highly obese men also experienced more heart failure, fatigue, pulmonary embolism and insomnia, but slightly lower rates of enlarged prostate.

Doctors should consider the diverse ways that increased weight affects their patients' health when they counsel or treat them, Patterson says.

"Effective and practical public health approaches to preventing weight gain and treating obesity are urgently needed," she says.