Abstract
BACKGROUND: Use of depot-medroxyprogesterone acetate (DMPA), norethisterone enanthate (NET-EN) and low-dose combined oral contraceptives (COCs) has been associated with loss of bone mineral density (BMD) in adolescents. However, the effect of using a combination of these methods over time in this age group is limited. The aim of this cross-sectional study was to investigate BMD in young women (aged 19-24 years) with a history of mixed hormonal contraceptive use. STUDY DESIGN: BMD was measured at the spine, hip and femoral neck using dual X-ray absorptiometry. Women were classified into three groups: (1) injectable users (DMPA, NET-EN or both) (n=40), (2) mixed COC and injectable users (n=13) and (3) non-user control (n=41). RESULTS: Women in the injectables-only user group were found to have lower BMDs compared to the non-user group at all three sites, and there was evidence of a difference in BMD between these two groups at the spine after adjusting for body mass index (p=.042), hip (p=.025) and femoral neck (p=.023). The mixed COC/injectable user group BMD values were lower than those for controls; however, there was no evidence of a significant difference between this group and the non-user group at any of the three sites. CONCLUSION: This study suggests that BMD is lower in long-term injectable users but not when women have mixed injectable and COC use.