Explored connection finds vitamin D may impact effectiveness of birth control methods
Researchers have found a link between estrogen-based contraceptives and vitamin D levels in women. The study, published in the Journal of Clinical Endocrinology & Metabolism, reveals that women who take estrogen-containing birth control pills have higher levels of vitamin D compared to those who do not. In contrast, when women cease using such contraceptives, their vitamin D levels significantly drop.
Vitamin D plays a crucial role in maintaining the correct balance of calcium and phosphorous in the blood and aiding the body's absorption of calcium, essential for bone health. Major sources of vitamin D include fish, eggs, and exposure to sunlight.
Dr. Quaker E. Harmon of the National Institutes of Health's National Institute of Environmental Health Sciences in Research Triangle Park, NC, initiated the study to examine any changes in vitamin D levels associated with oral contraceptives. The research team carried out a cross-sectional analysis of data from the Study of Environment, Lifestyle, and Fibroids - an investigation into reproductive health. This project utilized nearly 1,700 African-American women living in and around Detroit, MI, aged 23-34.
The study questioned women about their contraceptive use, including the type of contraceptive and duration, and included questions about outdoor activities and vitamin D supplements. In total, 1,662 women provided blood samples to determine levels of 25-hydroxy vitamin D, the most prevalent form of vitamin D in the body.
After adjusting for confounding variables such as seasonal exposure to light and adjusting for potential behavioral differences in outdoor activities, the study found that women using contraceptives containing estrogen had, on average, 20 percent higher levels of 25-hydroxy vitamin D. This association remained significant even after accounting for all factors.
During pregnancy, women produce increased levels of the active form of vitamin D to support the growth of the fetal skeleton. As a result, pregnant women are at an elevated risk of vitamin D deficiency and, subsequently, bone problems.
"Our study found that women who were using contraception containing estrogen tended to have higher vitamin D levels than other women," said Dr. Harmon. She added that further research was needed to understand the mechanics behind this association.
While the study focused solely on African-American women, Dr. Harmon noted that the same association had been observed in women of other races. However, in the United States, African-American women are more likely to be vitamin D-deficient, so even small increases or decreases in their vitamin D concentrations may be more important.
Dr. Harmon is continuing to follow this group of women to further investigate the relationship and working with another group of participants to better understand how vitamin D varies across the menstrual cycle.
References:[1] Harmon, Q. E., et al. (2022). The Association Between Contraceptive Use and Vitamin D Levels in black Women. Journal of Clinical Endocrinology & Metabolism.[4] Olsen, F. (2011). Vitamin D deficiency: Prevalence, causes, consequences, and benefits of vitamin D supplementation. Am Fam Physician, 83(3), 242–248.
- The study, conducted by Dr. Quaker E. Harmon, links estrogen-based contraceptives to higher levels of vitamin D in women, a nutrient crucial for bone health.
- In African-American women, particularly those living in the United States, higher vitamin D levels were observed in those using contraceptives containing estrogen.
- The association between contraceptive use and vitamin D levels remained significant even after accounting for factors such as seasonal exposure to light and behavioral differences in outdoor activities.
- The scientific investigation into reproductive health, known as the Study of Environment, Lifestyle, and Fibroids, found that women using estrogen-containing contraceptives had, on average, 20 percent higher levels of 25-hydroxy vitamin D.
- Pregnant women, who produce increased levels of the active form of vitamin D, are at an elevated risk of vitamin D deficiency and subsequent bone problems.
- Further research is necessary to understand the mechanisms behind the observed association between women's contraceptive use and vitamin D levels, as part of an ongoing investigation into women's health and health-and-wellness.
