By Maureen Williams, ND

Healthnotes Newswire (March 8, 2007)—Staying active may provide an unexpected benefit for women’s health: new research suggests that regular exercise might prevent uterine fibroids.

Uterine fibroids are noncancerous tumors made of cells from the muscular layer of the uterus. Many women with fibroids choose hysterectomy (surgical removal of the uterus) because of the severe pain and heavy menstrual bleeding fibroids cause. In fact, fibroids are the primary reason for hysterectomy in the United States.

Estrogen and progesterone are believed to play important roles in triggering fibroid formation and growth. Before menopause, the risk of developing fibroids increases with age; after menopause most fibroids shrink due to lower estrogen and progesterone levels. The risk is higher in African American women and in women whose menstrual cycles started at an early age.

Little is known about the effects of lifestyle on fibroid risk, but a new study, published in the American Journal of Epidemiology, looked at the relationship between physical activity and fibroids.

The researchers enrolled 1,189 African American and white women between 35 and 49 years old. The women answered questions about their exercise habits and had ultrasound testing to identify uterine fibroids.

Women who engaged in vigorous physical activity for at least four hours per week were less likely to develop uterine fibroids than women who were less active, and the higher their activity level, the more protected they were. Compared with the least active women, the most active women were 39% less likely to develop fibroids. For African American women, but not white women, being overweight was also linked to higher risk.

Previous research has found that physical activity can protect against breast cancer and uterine cancer, both hormone-sensitive tumors. Exercise reduces circulating levels of estrogen and progesterone, and this is likely to be one of the ways that it exerts its beneficial effects.

“These findings lend support to the idea that other lifestyle changes aimed at lowering hormone activity could reduce the risk of fibroids and possibly slow their growth,” commented Louise Tolzmann, a naturopathic doctor in Portland, Oregon, who works with women with breast cancer. “We know with breast cancer, for example, that diet can play a major role in prevention. A vegetarian diet is protective and a high-meat and high-dairy diet increases risk. Maybe these dietary patterns will be found—like exercise—to influence the risk or the course of uterine fibroids.”

The evidence from this study gives healthcare providers one more reason to urge women to become more active, especially African American women, among whom the rate of hysterectomy due to uterine fibroids is estimated to be 20%.

(Am J Epidemiol 2007;165:157–63)

Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.

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