Bone mineral density and history of oral contraceptive use.

To examine the relationship between oral contraceptive (OC) use and bone mineral density (BMD), we conducted a cross-sectional study on 352 white, nonsmoking, perimenopausal women aged 40-54 years. We measured bone mineral density of lumbar vertebrae 2-4 with dual photon absorptiometry and mid-radius and distal radius with single photon absorptiometry. After controlling for age, body mass, current physical activity, current calcium intake and history of breastfeeding, our analysis did not find substantial differences in BMD at any site between OC ever users and never users. However, OC ever users had slightly higher lumbar BMD among premenopausal women. No significant association was identified between recency of OC use and BMD. The results of our study suggest that when other factors are accounted for, OC use is not strongly associated with BMD among perimenopausal women, although we cannot exclude a slight beneficial effect.