Study Shows Relationship Between Body Shape And Endometriosis

BUFFALO, N.Y. -- A team of University at Buffalo researchers seeking to determine if the shape of a woman's body may signal her chances of developing endometriosis found that young women with the stereotypically feminine form of small waist and larger hips were six times more likely to develop the condition than those whose waist and hip measurements are nearly the same.

The positive finding only pertained to women 30 years of age or younger, however. The researchers found no significant relationship between body fat distribution and risk of endometriosis in study participants over 30.

Results of the study, the first to investigate the relationship of body-fat distribution and the risk of endometriosis, were published in the October issue of Obstetrics and Gynecology.

Endometriosis is a condition in which the tissue of the uterine lining (the endometrium) migrates into the pelvic region, often causing extreme pain and infertility. It affects up to 7 percent of women of reproductive age.

To determine if body-fat distribution may be a marker for risk of developing endometriosis, the UB researchers interviewed and took body measurements of 88 white women diagnosed with the condition through the Reproductive and Endometriosis Center, a private practice in Buffalo, and a matching group of women who did not have the disease.

The research team based its investigation on prior evidence indicating that a woman's hormonal makeup may influence the way fat is deposited in the body, and that the hormone estrogen may play a role in the development of endometriosis. The disease is almost nonexistent in premenstrual girls and post-menopausal women, except those receiving estrogen replacement therapy, the study noted.

"Because estrogen is important in endometriosis, and the ratio of androgens to estrogens appears to contribute to body-fat distribution, we might expect a characteristic deposition of body fat in women with endometriosis," said Susan E. McCann, a doctoral candidate in the UB Department of Social and Preventive Medicine and the study's lead author.

Study participants were divided into under-30 and over-30 age groups. Cases and controls were similar in age, education, weight, height, thigh circumference and body-mass index, a figure representing the ratio of weight to height.

Results showed that, in general, women with endometriosis tended to have smaller waists in relation to their hips, indicating a predominance of peripheral body fat, than those without the disease.

Within the two age groups, women under 30 with endometriosis tended to weigh less and have smaller waist and thigh measurements than controls. For these women, the risk of having endometriosis increased as the ratio of the waist-to-hip measurement decreased. Women under 30 with the smallest waist-to-hip ratio had a risk of endometriosis six times that of women with the largest waist-to-hip ratio.

Women in this age group with the disease also had lower waist-to-thigh ratios, another indication of peripheral fat accumulation, than those who did not. These women had a three times greater risk of endometriosis than controls with the highest waist-to-thigh ratio.

Among the older women, those with the disease tended to weigh slightly more, be shorter, and have larger waist, hip and thigh measurements than the controls, the study showed. However, in this group, the waist-to-hip ratio was not associated with risk of endometriosis.

"Our finding that peripheral body-fat predominance was associated with endometriosis lends additional evidence to the existence of a characteristic shape, possibly resulting from hormonal changes occurring with the disease," the researchers stated.

"These results may eventually provide clues to the causes of endometriosis."

Members of the team, in addition to McCann, were Jo L. Freudenheim, Ph.D., Sherri L. Darrow, Ph.D., Ronald E. Batt, M.D., and Maria A Zielezny, Ph.D.