Oral contraceptive use and bone density in adolescent and young adult women

BackgroundMost of the millions of oral contraceptive (OC) users are under 30 years of age and in the critical period for bone mass accrual.Study DesignThis cross-sectional study of 606 women aged 14–30 years examined both OC duration and estrogen dose and their association with bone mineral density (BMD) at the hip, spine, and whole body (dual-energy X-ray absorptiometry).ResultsOf 389 OC users and 217 nonusers enrolled, 50% were adolescents (14–18 years). Of OC users, 38% used “low-dose” OCs [<30 mcg ethinyl estradiol (EE)]. In adolescents, mean BMD differed by neither OC duration nor EE dose. However, 19- to 30-year-old women's mean BMD was lower with longer OC use for spine and whole body (p=.004 and p=.02, respectively) and lowest for >12 months of low-dose OCs for the hip, spine and whole body (p=.02, .003 and .002, respectively).ConclusionsProlonged use of today's OCs, particularly <30 mcg EE, may adversely impact young adult women's bone density while using these agents.