New finding hints at connection between vitamin D and contraceptives
Researchers report that utilizing estrogen-based birth control pills may lead to increased levels of vitamin D in women. Conversely, women who cease taking these contraceptives may experience a substantial decline in vitamin D levels.
Vitamin D's primary function is maintaining proper calcium and phosphorus levels in the blood, also contributing to the absorption of calcium, a vital element in bone structure. Food sources high in vitamin D include fish and eggs; however, approximately 90% of the vitamin is primarily produced through a chemical reaction in the skin upon exposure to sunlight.
Deficiency in vitamin D can lead to ailments such as rickets and osteomalacia, which cause softening of the bones. Given vitamin D's significance in bone development, it is especially crucial during pregnancy. In light of this, researchers from the National Institutes of Health's National Institute of Environmental Health Sciences in Research Triangle Park, NC, decided to investigate any links between vitamin D levels and the use of oral contraceptives.
The Connection between Vitamin D and Contraception
The researchers performed cross-sectional analysis using data from the Study of Environment, Lifestyle, and Fibroids (SELF), an examination focusing on reproductive health. The study involved nearly 1,700 African-American women aged 23-34 living in and around Detroit, MI. Data was collected regarding contraceptive use and time spent outdoors, as well as any vitamin D supplements taken.
Blood samples were obtained from 1,662 women to measure the most common circulating form of vitamin D, known as 25-hydroxy vitamin D. Pregnant women are known to produce increased levels of the active form of vitamin D to support the growth of the fetal skeleton, making them more susceptible to vitamin D deficiency and associated 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. Quaker E. Harmon. Even after accounting for confounding factors such as seasonal exposure to light, this effect remained significant. "We could not find any behavioral differences such as increased time spent outdoors to explain the increase," added Dr. Harmon. "Our findings suggest that contraceptives containing estrogen tend to boost vitamin D levels, and those levels are likely to fall when women cease using contraception."
After adjusting for confounding variables, the use of contraceptive pills, patches, or rings containing estrogen was associated with 20 percent higher levels of 25-hydroxy vitamin D. Current users of birth control displayed higher vitamin D levels, while past users had average levels.
Vitamin D Deficiency in Early Pregnancy
Recent findings, published in the Journal of Clinical Endocrinology & Metabolism, show that as a woman starts trying to become pregnant, she may face the risk of vitamin D deficiency. Dr. Harmon advises that women considering stopping birth control should ensure vitamin D levels are adequate during pregnancy.
Medical News Today asked Dr. Harmon to explain why estrogen-based contraception might affect vitamin D levels. "We do not know why vitamin D levels are higher," she responded. "Other work suggests that the levels of other vitamin D metabolites are modified when women use estrogen-containing contraception. This suggests that there may be alterations in the metabolism of vitamin D. Further research is needed."
Notably, the present study focused exclusively on African-American women. Dr. Harmon further explained that the same relationship has been observed in non-African-American women, implying that race might not play a role in this effect. In the United States, African-American women are more likely to be vitamin D-deficient, making small variances or declines in their vitamin D concentrations potentially more significant.
Dr. Harmon also plans to continue following the study participants to further investigate the relationship and is working on another group of participants to examine how vitamin D varies across the menstrual cycle. Learn about studies showing that higher vitamin D levels may lower cancer risk.
- The researchers' study using data from the SELF found that women using contraception containing estrogen had higher vitamin D levels compared to other women.
- Dr. Harmon noted that even after accounting for confounding factors such as seasonal exposure to light, this effect remained significant, suggesting that contraceptives containing estrogen tend to boost vitamin D levels.
- The study's findings imply that vitamin D levels are likely to fall when women cease using contraception, a potential concern for women considering stopping birth control.
- After adjusting for confounding variables, the use of contraceptive pills, patches, or rings containing estrogen was associated with 20 percent higher levels of 25-hydroxy vitamin D.
- Medical research suggests that deficiency in vitamin D, especially during pregnancy, can lead to ailments such as rickets and osteomalacia, which cause softening of the bones, making it crucial to maintain adequate vitamin D levels during pregnancy.
- The present study focused on African-American women, but Dr. Harmon mentioned that the same relationship has been observed in non-African-American women, implying that race might not play a significant role in the effect of estrogen-based contraception on vitamin D levels.
