Vitamin D and Uterine Fibroids

2013-11-29 15:24:23

Uterine fibroids, also known as uterine leiomyomas, are benign tumors of the uterine tissue that are thought to affect about one third of women. Uterine fibroid growth occurs in response to estrogen stimulation. For this reason, they typically affect women of reproductive age, and diminish in size after menopause. Small uterine fibroids are generally not problematic and do not give rise to serious symptoms; on the other hand, large fibroids can lead to subfertility, heavy bleeding, iron deficiency anemia, and may require surgical treatment.

Vitamin D is known for its role in a host of conditions, including immune health, cancer, respiratory illness such as asthma, and bone health to name a few. Its potential role in women’s reproductive health is less known. Laboratory studies have shown that the active metabolite of vitamin D can inhibit cell proliferation and extracellular matrix production in fibroid tissue culture, and can reduce fibroid volume in animals .⁽²⁾ This case-control study compared vitamin D status in women with and without uterine fibroids to identify a potential role for vitamin D in this condition in humans .⁽¹⁾

Subjects were women referred to two infertility clinics in Italy. “Cases” were 128 women who had to have at least one fibroid of at least 1cm diameter. “Controls” were 256 women of the same age with no uterine fibroids upon ultrasound.

Vitamin D levels were significantly lower in women with fibroids compared to healthy women. A total of 15% of women in the fibroid group had vitamin D deficiency, compared to only 7% of women in the control group, meaning that women with fibroids were at 2.4-fold greater odds of having vitamin D deficiency .⁽¹⁾ These findings are consistent with previous studies, which found that women with sufficient levels of vitamin D had 32% lower odds of having fibroids compared with women who had insufficient vitamin D insufficiency .⁽²⁾

Vitamin D is an emerging regulator of uterine leiomyoma development. Randomized controlled trials are need to assess whether vitamin D supplementation may be an effective therapy for uterine fibroids. Women with fibroids should have their vitamin D levels tested and supplement to achieve sufficient blood levels.