Is poor nutrition masking the effects of depomedroxyprogesterone acetate on bones in adolescent users?

Research in the developed countries has documented bone loss in adolescents who use depomedroxyprogesterone acetate (DMPA) as a contraceptive for less than two years. DMPA use often begins during adolescence in Bangladesh, a South Asian developing country, where more than 50% of women are undernourished. Poor nutrition is also associated with low bone mineral density (BMD) in South Asian women. We investigated the effects of long-term (two or more years) DMPA use on BMD in Bangladeshi women who started its use in their adolescence.

Lumbar spine and femur neck BMD were acquired using dual energy X-ray absorptiometry for 100 adolescents (50 DMPA users and 50 non-users) in a cross-sectional study in Dhaka, Bangladesh. Multivariate analysis was used to determine the associations between BMD and DMPA use. Stratified analysis of DMPA use investigated the determinants of BMD in both groups.

The participants (mean age 18 +/- 2 years) were generally below their ideal body weight. No significant differences in BMD were found between the two groups. Weight (odds ratio [OR] 0.96, 95 percent confidence interval [CI], 0.92-1.00) and height (OR 0.68, 95 percent CI 0.49-0.94) were independent determinants (p-value is less than 0.05) of lumbar and femur neck BMD, respectively.

Poor nutritional status, indicated by a less-than-ideal body weight, may be masking the effects of DMPA on bone loss among adolescent users. Our findings suggest that nutritional supplementation may be required with DMPA prescription to promote bone health in adolescent users who are approaching peak bone mass.