Uterine Fibroids Linked to Low Vitamin D Levels
Uterine fibroids, or leiomyomata, are noncancerous tumors that often result in bleeding and pain in premenopausal women. They are the leading cause of hysterectomy (surgical removal of the uterus) in the US.
Researchers led by Donna Baird, Ph.D., from the National Institute of Health found that women who had low vitamin D levels are more likely to develop uterine fibroids than those who had sufficient levels. Their study involved more than 1,000 women, aged 35-49, who were screened for fibroids using ultrasound. Participants’ blood samples were also used to measure their vitamin D levels, known as 25-hydroxy D. Levels of more than 20 nanograms per milliliter (ng/ml) of 25-hydroxy D were considered sufficient, although some experts consider higher levels are required for good health.
Vitamin D, also called the sunshine vitamin, is synthesized in the skin upon exposure to sunlight. It is also obtained from foods and supplements. Participants were asked about their sun exposure through questionnaires. The investigators found that those who reported spending more than one hour outdoors per day were 40% less likely to have fibroids. The estimated reduction in prevalence of fibroids was about the same for both blacks and whites.
Baird notes that their findings are consistent with laboratory studies, but more studies in women are needed. They are currently conducting another study in Detroit to see if the findings, which were from Washington, D.C., can be replicated.
Other NIH researchers, led by Darlene Dixon, D.V.M., Ph.D., are conducting more studies on fibroid development, by examining tissue samples of fibroids from study participants who had surgery.
National Institute of Environmental Health Sciences. Vitamin D may reduce risk of uterine fibroids. ScienceDaily.