Seventy-five studies were reviewed: 11 RCTs (n=544), 28 cohort studies (n=3,256), 32 cross-sectional studies (n=19,547), 3 case series (n=94) and 1 case report.
BMD.
Healthy premenopausal women: 46 studies, including 4 RCTs (n=246), were reviewed. All 4 RCTs reported no effect on BMD for OCs compared with baseline controls. Three of the 16 cohort studies, 7 of the 25 cross-sectional studies, and the case series reported positive effects of OCs on BMD; other studies reported no effect or negative effects.
Oligo/amenorrhoeic premenopausal women: 10 studies, including 3 RCTs (n=122), were reviewed. Two of the RCTs reported a positive effect of OCs on BMD; one compared with placebo and one compared to baseline. The third RCT reported no increase in BMD from baseline with oestrogen treatment. Five of the 6 cohort studies reported positive effects of OCs on BMD, while the case series reported negative effects.
Anorexic premenopausal women: 8 studies, including 3 RCTs (n=159), were reviewed. All 3 RCTs reported no effect of OCs on BMD. The 2 cross-sectional studies reported positive effects of OCs on BMD; other studies (2 cohort studies and 1 case series) reported no effect or negative effects.
Perimenopausal women: 11 studies, including 1 RCT (n=17), were reviewed. The RCT reported a non significant increase in BMD in OC users compared to baseline. All 4 cohort studies and 3 of the 5 cross-sectional studies reported positive effects of OCs on BMD; other studies (2 cross-sectional studies and 1 case series) reported no effect.
Bone metabolism (RCTs only).
Healthy premenopausal women: 3 of the 4 RCTs reported a positive effect of OCs on bone metabolism.
Oligo/amenorrhoeic premenopausal women: 1 RCT (n=45) reported a positive effect of OCs on bone metabolism. Anorexic premenopausal women: 1 RCT reported a non significant decrease from baseline in urinary N-telopeptides with OCs.
Other results were also presented.