Adequate levels of vitamin D may reduce the risk of uterine fibroids, according to a study published in the journal, Epidemiology. Women who had sufficient amounts of vitamin D were 32% less likely to develop fibroids than women with insufficient vitamin D.
The study, conducted from researchers at the National Institute of Health, consisted of 1,036 women, aged 35 to 49, living in the Washington, D.C. area from 1996 to 1999.
Researchers at The George Washington University and the Medical University of South Carolina screened participants for fibroids using ultrasound. Blood samples were used to measure the primary circulating form of vitamin D, know as 25-hydroxy D. Subjects with more than 20 nanograms per milliliter of 25-hydroxy D were categorized as sufficient.
Participants then completed a questionnaire on sun exposure. Those who reported spending more than one hour outside per day also had decreased risk of fibroids, estimated at a 40% reduction. Although fewer black women then white women had sufficient 25-hydroxy D levels, the estimated reduction in prevalence of fibroids was about the same for both ethnic groups.
Results of the study, are consistent with laboratory studies, but more studies in women are needed. Other studies have linked low vitamin D to weight gain in women and depression in adults.