Researchers at Boston University School of Medicine's (BUSM) Slone Epidemiology Center have discovered that women who eat large amounts of dairy products have a reduced risk for uterine fibroids (leiomyomata). The scientists based their discovery on statistics culled from the Black Women's Health Study. Their report has appeared in the American Journal of Epidemiology.
Black women have a two to threefold risk for the benign tumors known as uterine fibroids when compared to white women. These growths are the primary reason for removal of the uterus (hysterectomy) within the United States. It has been estimated that fibroids generate $2.2 billion every year in health care expenses.
Surveys of U.S. black women show that they tend to consume far fewer servings of milk products than do white women. As a result, black women tend to be deficient in calcium, phosphorus, and magnesium.
While the mechanism by which fibroids develop is still not well understood, growth factors and sex steroid hormones are believed to have some effect on the development of this condition. The scientists at Slone looked at consumption of dairy products because they thought it possible that these foods may affect a woman's sex hormones and may also have some protective antioxidant effects.
The Black Women's Health Study involved 59,000 study participants who joined the study in 1995. The women filled out questionnaires twice a year. The questionnaire asked the women if they'd been diagnosed with fibroids. The scientists also assessed the participants' diets twice a year, with the help of a questionnaire based on the National Cancer Institute's Block short-form food frequency questionnaire (FFQ).
A ten year follow-up found that there were 5,871 women who had been diagnosed with uterine fibroids. The scientists also found that after adjusting for certain risk factors, a high dairy intake seemed to have a protective effect on the participants who hadn't developed fibroids. The scientists believe that the lower dairy intake among black women may account for the discrepancy between white and black women in their rates for developing fibroids.
The incidence of fibroids went down 30% in women who consumed 4 or more servings of dairy per day, in comparison with women who ate less than one serving a day. Higher intakes of calcium, phosphorus as well as higher calcium to phosphorus ratios seemed to lower the risk, as well. The calcium to phosphorus ratio is an indication of the availability of the calcium to the body.
Associate professor of epidemiology at Boston University School of Public health, Lauren A. Wise, ScD said, "Although the exact mechanisms are unclear, a protective effect of dairy consumption on uterine fibroids risk is plausible, as calcium, a major component of dairy foods, may reduce cell proliferation."
Wise is a senior epidemiologist at Slone and the lead author of this study. "This is the first report showing an inverse association between dairy intake and fibroid risk. If confirmed, a modifiable risk factor for fibroids, a major source of gynecologic morbidity, will have been identified," concludes Wise.