Discovered association between vitamin D and contraceptive methods
Women using estrogen-based birth control pills may experience elevated levels of circulating vitamin D, according to a study led by Dr. Quaker E. Harmon at the National Institutes of Health's National Institute of Environmental Health Sciences in Research Triangle Park, NC. Conversely, women who cease taking these contraceptives may witness a significant drop in their vitamin D levels.
Vitamin D plays a crucial role in maintaining proper calcium and phosphorous levels in the blood. It aids in the body's absorption of calcium, an essential component of bones. Foods like fish and eggs are high in vitamin D, while around 90 percent of the vitamin is produced in the skin via a chemical reaction due to sunlight exposure. Vitamin D deficiency can lead to rickets and osteomalacia (softening of the bones), making it particularly important during pregnancy.
In the study, the researchers analyzed data from the Study of Environment, Lifestyle, and Fibroids (SELF), an investigation of reproductive health that included almost 1,700 African-American women aged 23-34 living in and around Detroit, MI. The participants answered questions about their contraceptive use, sun exposure, and if they took any vitamin D supplements. They also provided blood samples to determine levels of the most common circulating form of vitamin D, called 25-hydroxy vitamin D.
The results revealed that women using contraception containing estrogen tended to have higher vitamin D levels than other women. This finding remained significant after adjusting for confounding factors like seasonal exposure to light. Dr. Harmon and her team could not find any behavioral differences, such as increased time spent outdoors, to explain the increase. They found that using contraceptive pills, patches, or rings containing estrogen was associated with 20 percent higher levels of 25-hydroxy vitamin D.
Women who were current users of birth control had higher vitamin D levels, while past users had average levels. These findings, published in the Journal of Clinical Endocrinology & Metabolism, suggest that a woman planning to stop using birth control should take steps to ensure adequate vitamin D levels while trying to conceive and during pregnancy.
Researchers are continuing to study this relationship further, investigating how vitamin D levels vary across the menstrual cycle. Although the study focused solely on African-American women, Dr. Harmon noted that the same association has been observed in women not of African descent.
Regarding the mechanism behind the link between estrogen-based contraception and increased vitamin D levels, Dr. Harmon stated that further work is needed to clarify the potential alterations in the metabolism of vitamin D. The exact relationship between the two remains uncertain.
It's worth noting that while estrogen-based contraception may influence vitamin D status indirectly through lifestyle or metabolic changes, it does not directly lead to higher levels of vitamin D. Other factors like sun exposure, diet, or overall health status likely play a more significant role in vitamin D levels.
- Women using contraceptives containing estrogen tend to have higher vitamin D levels compared to other women, as indicated by the study led by Dr. Quaker E. Harmon.
- The increase in vitamin D levels among women using contraceptives was not explained by any behavioral differences, such as increased time spent outdoors, according to the study.
- The study, focused on African-American women, revealed that using contraceptive pills, patches, or rings containing estrogen was associated with 20 percent higher levels of 25-hydroxy vitamin D.
- The results of the study emphasize the importance of ensuring adequate vitamin D levels for women who are planning to stop using birth control and especially during pregnancy.
- Researchers are ongoing in their investigation of the relationship between vitamin D levels and the menstrual cycle, aiming to gain a better understanding of the link between estrogen-based contraception and increased vitamin D levels.
- Although estrogen-based contraception may influence vitamin D status, it does not directly cause higher levels of vitamin D. Factors like sun exposure, diet, or overall health status are likely more significant in determining vitamin D levels.
