Steroidal contraceptive use is associated with lower bone mineral density in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common condition affecting reproductive-aged women with features including hyperandrogenism and menstrual irregularity frequently treated with hormonal steroidal contraceptives. Women with PCOS appear to have lower bone mineral density (BMD). While steroidal contraceptives may positively affect bone health, their effect on BMD in PCOS is not known. The aim of this study was to assess BMD in women with PCOS according to recent contraceptive use. A cross-sectional analysis of 95 pre-menopausal overweight or obese sedentary women with PCOS [age 29.4 ± 6.4 years, body mass index (BMI) 36.1 ± 5.3 kg/m²] who either recently took steroidal contraceptives (ceased 3 months prior) or were not taking steroidal contraceptives was conducted. Clinical outcomes included BMD, anthropometry, insulin, glucose, reproductive hormones, dietary intake and vitamin use. BMD was significantly lower for women who used contraceptives compared to those who did not (mean difference 0.06 g/cm² 95 % confidence interval −0.11, −0.02, p = 0.005). In regression models, lower BMD was independently associated with contraceptive use (β = −0.05, 95 % CI −0.094, −0.002, p = 0.042), higher testosterone (β = −0.03, 95 % CI −0.05, −0.0008, p = 0.043) and lower BMI (β = 0.006, 95 % CI 0.002, 0.01, p = 0.007) (r ² = 0.22, p = 0.001 for entire model). We report for the first time that overweight and obese women with PCOS with recent steroidal contraceptive use had lower BMD in comparison to non-users independent of factors known to contribute to BMD. Whether this observation is directly related to steroidal contraceptive use or other factors requires further investigation.