A recent study published in the journal Medicine found that vitamin D supplementation in patients with low vitamin D levels reduced the progression of “small burden” uterine fibroids.
Uterine fibroids are a common benign tumor of the female reproductive tract. Women who are symptomatic typically show menstrual disorders, heavy bleeding, anemia and pelvic pain. Many factors influence therapy interventions, including severity of symptoms, tumor characteristics, patient age and fertility needs. Hysterectomy is still a common surgical approach for women with symptomatic uterine fibroids, but there are other conventional medical treatments with less risks.
Symptomatic uterine fibroids often require medical treatment. However, “small burden” uterine fibroids, ones that present limited disease and symptoms, can benefit from a therapeutic approach to prevent progression of the disease to a symptomatic disease.
Recent studies suggest that low vitamin D status is associated with an increased risk of uterine fibroids. Animal studies have discovered that vitamin D reduced fibroid size, indicating that vitamin D supplementation may provide an affordable and effective therapy of uterine fibroids. However, this had yet to be explored in humans. Therefore, researchers recently hypothesized that vitamin D supplementation may be an effective and safe therapy for those suffering from uterine fibroids.
The researchers enrolled 108 patients with “small burden” uterine fibroids. At baseline, all women underwent uterine evaluation and testing. A total of 53 participants received 50,000 IU of vitamin D weekly for eight weeks, followed by a maintenance dose of 2,000 IU daily for a year. The remaining 55 patients who had either refused supplementation or did not perform it adequately became the control group. After 12 months, the patients underwent a second uterine evaluation and testing. Progression to extensive disease was defined as an increase in size to >50mm and/or the development of one or more fibroids over the 12-month period.
The researchers discovered the following:
- The average baseline vitamin D levels were 19.9 ng/ml and 21.4 ng/ml for the study and control group, respectively. A vitamin D status below 30 ng/ml was considered low.
- At the 12 month call back, the average vitamin D levels were 30.7 ng/ml and 23.1 ng/ml for the study and control group, respectively.
- Location and number of lesions remained the same from initial to final ultrasound in both groups.
- A significant increase in the diameter and volume of the fibroids was seen in the control group (p<0.001), while no significant difference in fibroid diameter or volume was seen in the study group.
- A negative correlation between baseline 25(OH)D and both volume and total fibroids emerged (p<0.001).
- The progression to extensive disease was significantly lower in the study group compared with control group (13.2% vs 30.9%).
After adjusting for confounding factors, 25(OH)D status remained significantly inversely associated with the volume, total fibroid count and progression of uterine fibroids.
The researchers concluded,
“Our results confirm the correlation between hypovitaminosis D and uterine fibroids since we found that lower levels of vitamin D are related to a more severe uterine disease, in terms of volume of the largest fibroid (r = −0.18, P = 0.01) and total volume of fibroids (r = −0.19, P = 0.01).”
The main limitation of this study was its use of an “as treated analysis”, in which the patients were assigned to the control group based on whether they complied to the recommended supplementation. This type of analysis introduces selection bias into the study. The patients who did not adhere to the vitamin D recommendation may have had various reasons for this, such as not responding well to the supplements or not gaining benefits from supplementation.
The study found that patients with “small burden” uterine fibroids and vitamin D deficiency were able to reduce the rate of progression to extensive disease by supplementing with vitamin D.
Chapman, Cailin & Cannell, JJ. Vitamin D supplementation may reduce progression of uterine fibroids. The Vitamin D Council Blog & Newsletter, 1/4/2017.
Ciavattini, Andrea MD, PhD. et al. Hypovitaminosis D and “small burden” uterine fibroids: Opportunity for a vitamin D supplementation. Medicine, December 2016.