OBJECTIVE: To identify possible predictive factors of higher bone loss, defined as at least 5%, at the spine or femoral neck, over time in depot medroxyprogesterone acetate (DMPA) users.
METHODS: Bone mineral density (BMD) was measured at the lumbar spine and femoral neck every 6 months in 240 white, African-American, and Hispanic women using DMPA. For the purpose of analysis, an arbitrary value of at least 5% BMD loss from the baseline value after 24 months of DMPA use at either the lumbar spine or the femoral neck was considered as higher BMD loss. Logistic regression analysis was then used to examine factors predictive of at least 5% BMD loss at either site.
RESULTS: Of the initial 240 DMPA users, 95 completed 24 months of follow-up. Forty-five of the 95 DMPA users (47.4%) had at least 5% BMD loss at the lumbar spine or femoral neck by 24 months. Multivariable logistic regression model showed that at least 5% BMD loss was associated with current smoking (adjusted odds ratio [OR] 3.88, 95% confidence interval [CI] 1.26–11.96), calcium intake (in 100 mg) (OR 0.81, 95% CI 0.65–0.99), and parity (OR 0.49, 95% CI 0.29–0.82). Age, race or ethnicity, previous contraceptive use, and body mass index were not associated with higher BMD loss.
CONCLUSION: The risk of higher BMD loss associated with DMPA use may be reduced by quitting smoking and increasing calcium intake. Having had a child is also protective.
LEVEL OF EVIDENCE: II
In depot medroxyprogesterone acetate users, the odds of losing at least 5 bone mineral density are 3.9 times higher for smokers than for nonsmokers.
From the Department of Obstetrics and Gynecology and the Center for Interdisciplinary Research in Women's Health, The University of Texas Medical Branch, Galveston, Texas.
Dr. Berenson is supported by R01HD39883 and K24HD043659, the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
Presented at the 42nd Annual Meeting of the Society for Epidemiologic Research, June 23–26, 2009, Anaheim, California.
The content is solely the responsibility of the authors and does not necessarily represent the official views of the Eunice Kennedy Shriver National Institute of Child Health and Human Development or the National Institutes of Health.
Corresponding author: Mahbubur Rahman, MD, PhD, MPH, Department of Obstetrics and Gynecology, Center for Interdisciplinary Research in Women's Health, University of Texas Medical Branch, Galveston, TX 77555-0587; e-mail: firstname.lastname@example.org.
Financial Disclosure: The authors did not report any potential conflicts of interest.