RESUMO
CONTEXT: Previous studies have shown that the prevalence of polycystic ovary syndrome (PCOS) may vary according to race/ethnicity, although few studies have assessed women of different ethnicities who live in similar geographic and socio-economic conditions. OBJECTIVE: To determine the prevalence of PCOS in an unselected multiethnic population of premenopausal women. DESIGN: A multicenter prospective cross-sectional study. SETTINGS: The main regional employers of Irkutsk Region and the Buryat Republic, Russia. PARTICIPANTS: During 2016-19, 1398 premenopausal women underwent a history and physical exam, pelvic ultrasound, and testing during a mandatory annual employment-related health assessment. MAIN OUTCOME MEASURES: PCOS prevalence, overall and by ethnicity in a large medically unbiased population, including Caucasian (White), Mongolic or Asian (Buryat), and mixed ethnicity individuals, living in similar geographic and socio-economic conditions for centuries. RESULTS: PCOS was diagnosed in 165/1134 (14.5%) women who had a complete evaluation for PCOS. Based on the probabilities for PCOS by clinical presentation observed in the cohort of women who had a complete evaluation we also estimated the weight-adjusted prevalence of PCOS in 264 women with an incomplete evaluation: 46.2 or 17.5%. Consequently, the total prevalence of PCOS in the population was 15.1%, higher among Caucasians and women of Mixed ethnicity compared to Asians (16.0% and 21.8% vs. 10.8%, pz <0.05). CONCLUSIONS: We observed a 15.1% prevalence of PCOS in our medically unbiased population of premenopausal women. In this population of Siberian premenopausal women of Caucasian, Asian and Mixed ethnicity living in similar geographic and socio-economic conditions, the prevalence was higher in Caucasian or Mixed than Asian women. These data highlight the need to assess carefully ethnic-dependent differences in the frequency and clinical manifestation of PCOS.