Inadequate Vitamin D Status in Adolescents with Substantial Bone Mineral Density Loss During the Use of Depot Medroxyprogesterone Acetate Injectable Contraceptive: A Pilot Study

Abstract

Study Objective To examine vitamin D and parathormone (PTH) levels in adolescents who experienced substantial bone mineral density (BMD) loss during depot medroxyprogesterone acetate (DMPA) use. Design A non-randomized, multi-center study, during which DMPA was administered every 12 weeks and evaluation of lumbar spine and hip BMD by dual-energy X-ray absorptiometry (DXA) was conducted every 6 months. A blood sample for vitamin D and PTH measurements was obtained from adolescents who experienced >5% BMD loss. Vitamin D deficiency was defined as 25-hydroxyvitamin D (25OHD) level of <20ng/mL, insufficiency as 25OHD level of 20-30ng/mL, and sufficiency as 25OHD level of >30ng/mL. Results Evaluation of vitamin D and PTH was carried out in 15 participants who experienced BMD loss of ≥5% during DMPA use. At initiation of DMPA, participants had mean (+SE) age 17+1years, gynecologic age 61+4 months, and body mass index 24+1.5kg/m2. Racial/ethnic distribution was: Caucasian–7 girls, Hispanic–4 girls, African-American–3 girls, and other–1 girl. Six participants had BMD loss of >5% after 2 DMPA injections, five after 3 injections, one after 5 injections, one after 8 injections, one after 10 injections, and one after 13 injections. Only one girl (7%) had sufficient vitamin D. The other participants had vitamin D insufficiency (50%) or deficiency (43%). Participants' mean (+SE) PTH was 22+4pg/mL (reference range 7-53pg/mL), and mean (+SE) 1,25-dihydroxyvitamin D was 56+5pg/mL (reference range 22-67pg/mL). Conclusions Inadequate vitamin D status was evident among the majority of female adolescents who experienced a substantial BMD loss while using DMPA.