In the journals

Weight loss reduces urinary incontinence in heavy women

Losing weight reduces the risk factors for many diseases, especially cardiovascular disease and type 2 diabetes. Shedding just 10 pounds, for example, can lower blood pressure. Weight loss also lowers blood sugar and improves cholesterol levels. Now, a new benefit can be added to the list: reduced urinary incontinence in women who are overweight or obese. In a randomized trial funded by the National Institutes of Health, moderate weight loss in a group of heavy women who undertook a six-month diet and exercise program cut the frequency of urinary incontinence episodes by nearly a half. Results were published in The New England Journal of Medicine (Jan. 29, 2009).

Urinary incontinence affects more than 13 million women in the United States. It not only causes inconvenience and emotional stress, it also raises the risk of falls, fractures, and nursing home admissions. Obesity has long been associated with urinary leakage in women, but until now, there's been little research to confirm that losing weight would help reverse the problem — or to suggest how much weight loss would be needed.

In the New England Journal of Medicine study, investigators with the Program to Reduce Incontinence by Diet and Exercise (PRIDE) at the University of California at San Francisco worked with 338 overweight or obese women (average age 53) who leaked urine at least 10 times per week. Participants were randomly assigned to either an intensive program of diet, exercise, and behavioral modification or to a control group that was instructed in the benefits of weight loss, exercise, and healthy eating but received no training to help them modify their habits. At the start of the study, subjects were given self-help bladder-control booklets and completed seven-day voiding diaries in which they identified incontinence episodes as stress incontinence (urine leakage with coughing, sneezing, straining, or exercise), urge incontinence (urine leakage after feeling a sudden need to urinate), or other.

The weight loss group met weekly for six months in one-hour sessions led by experts in exercise, nutrition, and behavior change. They were given a low-calorie (1,200–1,500 calories per day), low-fat diet and told to gradually increase moderate-intensity physical activity up to at least 200 minutes per week. The control group participants met four times in one-hour group sessions. After six months, women in the first group had lost an average of 17 pounds and had 47% fewer urinary incontinence episodes; the control group participants lost an average of 3 pounds and reported 28% fewer episodes. A higher proportion of the women in the weight loss group (41%) than in the control group (22%) experienced a 70% or greater drop in the frequency of incontinence episodes. Perhaps not surprisingly, weight-loss participants reported feeling happier about the change in their incontinence, compared with the control group.

The PRIDE investigators acknowledge that their findings may not apply to all women. They selected participants partly because they lacked certain medical conditions and were willing to stick with the behavioral program. Also, it was impossible to "blind" the experiment so that neither participants nor researchers would know which group was receiving the treatment. Nonetheless, the study strongly suggests that weight loss reduces incontinence episodes, possibly by reducing pressure on the bladder and pelvic floor. Understanding this may help women concerned about urinary leakage during exercise to stick with their workouts, knowing that doing so could improve urinary incontinence down the road.