A recent study found that for every 10 ng/ml decrease of vitamin D status, there was a 14% increased risk of developing high-risk human papillomavirus (HPV) infection among sexually active women.
HPV is the most common sexually transmitted infection. HPV can develop from having vaginal, anal or oral sex with someone who already has the virus. There are over 100 varieties of HPV with approximately 40 types that can infect the cervico-vaginal region. In most cases, HPV disappears on its own and does not cause health problems. However, when HPV does not go away, it can cause health problems like genital warts and cancer.
Individuals can reduce their risk of developing HPV by getting vaccinated and using protection. The vaccine protects against HPV types 6, 11, 16 and 18, the four HPV types that are responsible for the vast majority of HPV associated disease. A new vaccine was approved for protection against 9 HPV types in December 2014. In addition, routine screening for women aged 21 to 65 years old is recommended.
Vitamin D plays a large role in the immune system by increasing the expression of anti-microbial peptides and activating killer T cells to detect and destroy invading pathogens. Therefore, researchers recently hypothesized that low vitamin D status is linked to an increased risk for HPV.
In order to test this hypothesis, the researchers examined data from the National Health and Nutrition Examination Survey (NHANES 2003-2006). At this time, none of the HPV vaccines were introduced.
The researchers studied a total of 2,353 sexually active women with available testing results of cervicovaginal HPV infection status and vitamin D status. The analysis focused on tumor causing HPV types and the four types that are prevented by vaccine, which they referred to as “vaccine type HPV infection.”
Here is what the researchers found after adjusting results for age, race/ethnicity and marital status:
- The odds of high-risk HPV infection increased per each 10 ng/ml decrease of vitamin D status by 14%.
- The odds of vaccine type HPV infection were nearly tripled in women with severe vitamin D deficiency as defined by levels less than 12 ng/ml compared to those with levels of 30 ng/ml or greater (aOR 2.90; 95% CI, 1.32 – 6.38).
- The odds of vaccine type HPV infection were more than doubled in women with vitamin D deficiency defined by levels between 12 and 19 ng/ml compared to women with levels of 30 ng/ml or greater (aOR 2.19; 95% CI, 1.98 – 4.45).
- The odds of vaccine type HPV infection were more than doubled in women with vitamin D insufficiency defined by levels between 20-29 ng/ml compared to women with levels of 30 ng/ml or greater (aOR 2.19, 95% CI, 1.22 – 3.393).
The researchers concluded,
“In conclusion, results from this US nationally representative sample support the hypothesis that vitamin D status, assessed by serum 25(OH)D levels, is inversely associated with prevalence of cervicovaginal HPV infection in sexually active women.”
The study design was cross-sectional, meaning the study could not prove causality. On the other hand, the study also had its strengths. It consisted of a very large sample representative of the U.S. population. Lastly, the study adjusted for multiple confounding variables.
Tovey, A. & Cannell, JJ. New study reports link between low vitamin D status and HPV among women in the U.S. The Vitamin D Council Blog & Newsletter, February, 2016.