Many women in the study who had fecal incontinence also had another medical condition, such as major depression or diabetes, and often experienced urinary incontinence in addition to FI. The findings are reported in the American Journal of Obstetrics and Gynecology.

"Increased attention should be paid to this debilitating condition, especially considering the aging of our population and the available treatments for FI," says senior author Dee E. Fenner, M.D., associate professor of obstetrics and gynecology, and director of gynecology, at the University of Michigan Medical School. "It is very important to the health of women that clinicians are aware of the prevalence of FI and can treat their patients accordingly."

The study, led by the University of Washington, was a postal survey of 6,000 women ages 30-90 who were enrolled in a large HMO in Washington state (the condition also affects men, but only women were involved in the study). Of the 64 percent who responded, the prevalence of FI was found to be 7.2 percent, with the occurrence increasing notably with age. FI was defined as loss of liquid or solid stool at least monthly.

The study was the first, to the authors' knowledge, to examine major depression as a potential risk factor for FI. They say FI could be a contributing factor to major depression in some cases, and major depression could be a contributing factor to FI in other cases.

FI can occur after damage to the anal sphincter muscles or scarring to the rectum, causing it to be unable to hold stool. Ulcerative colitis, Crohn's disease and some other conditions can cause this scarring to occur. Another contributing factor can be the stretching of the nerves that supply the sphincters, called the pudendal nerves, which can occur with childbirth, old age, trauma, or with medical diseases that affect the nerves, such as diabetes. Without intact nerves to stimulate the sphincters, the sphincters may undergo atrophy.

Because of the nature of the condition, people who have FI often do not discuss it with their doctors, experts say. That is why the study's authors encourage clinicians to take a more active role in finding out if their patients are experiencing FI, especially among patients age 50 or older. They note that while FI is present in many elderly women, it should not be considered merely a normal part of aging. They also encourage women to discuss the issue with their doctors.

It also is important for women and their doctors to be aware of the conditions that often go along with FI. Researchers found that women in the study with FI were more likely to have: A higher number of deliveries Urinary incontinence A previous hysterectomy Another medical condition as well, such as major depression or diabetes A history of operative vaginal delivery, such as those using forceps or a vacuum-assisted device.

The impact of incontinence on the quality of life of the respondents was "significant," says Fenner, who is one of the founders of the Michigan Bowel Control Program at the University of Michigan Health System. "We found that half of the subjects with FI reported that their bowel symptoms had a large impact on their quality of life," she notes.

Treatments that can help people manage FI can range from changes in diet and exercise, to medications that improve the formation of stools, to surgery that repairs the sphincter muscles. In some cases, an artificial bowel sphincter can be implanted under the skin to mimic the natural function of the anal sphincter. Biofeedback - which involves daily exercises to improve the strength of muscles used to hold back a bowel movement - also is an option for some patients.

The lead author of the study was Jennifer L. Melville, M.D., M.P.H., of the Department of Obstetrics and Gynecology and the Department of Psychiatry & Behavioral Sciences at the University of Washington. In addition to Melville and Fenner, other authors were Ming-Yu Fan, Ph.D., of the Department of Psychiatry & Behavioral Sciences at the University of Washington and Katherine Newton, Ph.D., of the Center for Health Studies at the Group Health Cooperative of Puget Sound of Seattle.

med.umich

The researchers found that the mice lacking VMH leptin receptors showed the same degree of body weight gain as those engineered to lack leptin receptors in the ARC. What's more, the researchers found that knocking out both types of neurons showed an additive effect on weight gain in the animals. Their measurements in the mice revealed that such weight gain was due to an increase in fat stores.

Importantly, when the researchers fed the mice deficient in VMH leptin receptors a high-fat, high-sugar diet, they found that the animals rapidly gained weight throughout the feeding period. In contrast, normal mice gained some weight, but leveled off during the feeding period. The knockout mice continued to gain weight, found the researchers, because they did not suppress their food intake, as did normal mice.

The researchers noted that the combined effects on obesity of the deficiency of VMH leptin receptors and high-fat feeding "were greater than expected from the individual components added together.

"This synergistic interaction strongly suggests that leptin action on [the VMH neurons] plays a particularly important role in resisting high-fat-diet-induced obesity."

Lowell and his colleagues concluded that "In total, these findings suggest that the ability of leptin to restrain body weight is distributed to a number of different sites in the brain."

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