Contrasting Bone Profiles in PCOS Are Related to BMI: A Systematic Review and Meta-analysis

Controversial results have emerged regarding whether polycystic ovary syndrome (PCOS) is protective or increases the risk of bone frailty.

This study investigated whether the PCOS condition affects bone parameters of premenopausal women. This is an update for a previous meta-analysis published in 2019.

We searched MEDLINE and Embase.

Studies were considered eligible for the update if published in English between October 1, 2018, and December 31, 2023. The diagnosis of PCOS should be based on National Institutes of Health criteria, the Rotterdam Consensus, Androgen Excess & PCOS Society criteria, or International Classification of Diseases codes in women over 18 years old. Only records with the Newcastle-Ottawa Scale ≥ 6 were selected for data extraction.

Data were extracted by 2 independent reviewers.

We identified 31 studies that met the inclusion criteria for qualitative analysis from 3322 studies in the whole period (1990-2023). Overall, cross-sectional studies included 1822 individuals with PCOS and 1374 controls, while cohort studies incorporated 30 305 women with PCOS and 10,1907 controls. Contrasting profiles emerged after stratification using a body mass index (BMI) cutoff of 27 kg/m2. Individuals with PCOS and a BMI <27 kg/m2 exhibited lower vertebral and nonvertebral bone density, reduced bone turnover marker (osteocalcin), and increased bone resorption marker (C-terminal type I collagen) levels. Conversely, individuals with PCOS and a BMI ≥27 kg/m2 exhibited increased vertebral and nonvertebral bone mineral density, with no significant changes in bone formation and resorption markers (except osteocalcin).

The findings of this study alert for a low bone mass, low bone formation, and increased bone resorption PCOS with a BMI <27 kg/m2.