Bone mineral density, fracture, and vitamin D in adolescents and young women using depot medroxyprogesterone acetate

Study objective: To evaluate bone mineral density (BMD) in adolescents and young adults treated with depot medroxyprogesterone acetate (DMPA).

Design, setting, participants: Eighty-three healthy subjects, 13-20 years old, who received at least 3 DMPA injections in an urban adolescent clinic and underwent dual energy x-ray absorptiometry (DXA) were evaluated by chart review.

Main outcome measures: Anthropometric data, DMPA use, BMD of the spine and hip, fracture history, and vitamin D status were collected.

Results: Subjects were a median age of 16.4 years old (range 13-20 years) when DMPA was initiated. The median number of DMPA injections was 5 (range 3-18) before the first DXA. At the spine and hip, respectively, BMD was normal (Z-score > -1.0 SD) for most subjects (79%, 86%). Subjects who received > 5 injections were more likely to have low spinal BMD (Z-score ≤ -2.0 SD) at first DXA (P = .018). In 15 subjects with repeat DXA measurements, after an additional median 6 injections, spinal BMD Z-score decreased by -0.33 ± 0.10 (mean ± SD, P = .004), as did absolute BMD at the hip (-0.019 ± 0.007 g/cm(2), P = .014). History of fracture was not associated with initial or subsequent BMD measurements. Most (12/13, 92.3%) subjects with vitamin D measurements were deficient (25-hydroxy vitamin D < 20 ng/mL).

Conclusions: Most subjects on DMPA had normal BMD at first DXA. Low spinal BMD was associated with longer DMPA use, and some BMD measurements declined with prolonged use. Fracture history is not an absolute contraindication to DMPA use in this population. Studies are needed to determine possible benefits of vitamin D supplementation in DMPA users.