Biopsychosocial variables associated with substantial bone mineral density loss during the use of depot medroxyprogesterone acetate in adolescents: adolescents who lost 5% or more from baseline vs. those who lost less than 5%.

BACKGROUND

It is unclear why some adolescents experience substantial bone mineral density (BMD) loss, while others experience a minimal decrease during depot medroxyprogesterone acetate (DMPA) use. We examined biopsychosocial factors in adolescents who experienced ≥5% BMD loss from baseline compared with adolescents who experienced <5% BMD loss during DMPA use.

STUDY DESIGN

A multicenter, prospective, nonrandomized study of 181 female adolescents who initiated DMPA for contraception was conducted. BMD (by dual-energy X-ray absorptiometry) and serum estradiol were measured at initiation and every 6 months for 240 weeks of DMPA use.

RESULTS

Half of participants experienced BMD loss of ≥5% from baseline at the hip, and a quarter experienced BMD loss of ≥5% at the lumbar spine (BMD substantial losers, SL). Hip and lumbar spine BMD-SL received a significantly greater number of DMPA injections than non-SL (p<.001). Decreased estradiol levels did not statistically differ between BMD loss subgroups. Hip BMD-SL had significantly lower baseline body mass index (BMI) than non-SL (p=.002), and there was an inverse relationship between weight gain and degree of BMD loss. Mean calcium intake was significantly lower (p<.05) in hip BMD-SL, and reported alcohol use was significantly higher (p<.05) in lumbar spine BMD-SL compared with non-SL.

CONCLUSIONS

BMD loss of ≥5% was more common at the hip than at the lumbar spine among adolescents using DMPA. Decreased serum estradiol levels did not correlate with magnitude of BMD loss. Lower BMI and calcium intake and greater alcohol use were associated with greater BMD loss in adolescents using DMPA.