Oral contraceptive use associated with higher levels of vitamin D – thesis

Created June 2012

Oral contraceptive use and vitamin D status among women ages 15-44 in the US: a cross- sectional study

Brinker, Kimberly Ann (2012)

Master's Thesis (158 pages)

Committee Chair / Thesis Adviser: Sullivan, Kevin M Sharma, Andrea (CDC);

Committee Members: Oraka, Emeka (ICF International);

Research Fields: Health Sciences, Epidemiology

Partnering Agencies: CDC

Program: Career Masters of Public Health (Applied Epidemiology)

Purpose: This analysis was conducted to determine the association between oral

contraceptive (OC) use and vitamin D status in women ages 15-44 by analyzing data

from the National Health and Nutrition Examination Survey (NHANES) 2001-2006.

Methods: The sample was limited to women ages 15-44 who were not pregnant or

breastfeeding, had no history of having an ovary removed or hysterectomy, and were not

taking any forms of estrogen and progestin for any reason other than OC. Characteristics

including age, race, income, body mass index (BMI), dietary supplement use, and

seasonality were analyzed.

Women with serum 25(OH)D levels <19ng/mL were considered vitamin D insufficient while those with serum 25(OH)D levels >19ng/mL were considered sufficient.

A logistic regression model was used to estimate prevalence ratios of vitamin D insufficiency by oral contraceptive use when taking the aforementioned characteristics into account.

Results: OC use was significantly associated with vitamin D status when accounting for

age, race, income, BMI, dietary supplement use, and seasonality.

Women using OC had a lower prevalence of vitamin D insufficiency than non-OC users ( prevalence ratio 0.59 ).

Among women who were categorized as vitamin D insufficient, 19.1% were OC users

whereas 44.6% were non-OC users.

Conclusion: The findings suggest that OC use does affect serum 25(OH)D concentrations.

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