Eastern Siberia PCOS Epidemiology & Phenotype Study (ESPEP Study)

Polycystic Ovarian Syndrome (PCOS) has a high prevalence and is a significant reproductive, metabolic, and psychosocial disorder. Several studies have demonstrated that PCOS affects from 6% (defined by NIH 1990 criteria) to 19.5% (under Rotterdam 2003 criteria) of reproductive-aged women (Jalilian et al., 2015; Bozdag et al., 2016). The prevalence of PCOS and its symptoms may vary according to geography and race/ethnicity (Huang et al., 2016; Ding et al., 2017). Clinical studies indicate variations in the presence and severity of PCOS and its clinical symptoms: hirsutism, obesity, insulin resistance by race and ethnicity. Unfortunately, there is a lack of data on the prevalence of PCOS and its phenotype in many geographic regions, in particular, in one of the largest countries in the world, Russia.

Objectives: To determine the prevalence of PCOS and the PCOS phenotypes in unselected (medically unbiased) premenopausal women in the Eastern Siberia region.

Study design and population: this is the multicenter, institution-based, cross-sectional Eastern Siberia PCOS Epidemiology & Phenotype (ESPEP) Study, conducted in Irkutsk Region and the Burjat Republic (Russia) during 2016-2019 yrs. ESPEP included premenopausal women aged 18 to 44 yrs, Caucasians, Asians, or those of mixed-race, recruited during an obligatory early medical employment assessment, and provided written informed consent. The study is approved by the Institutional Ethics Committee of the Scientific Center for Family Health a Human Reproduction (Irkutsk, Russian Federation).

Methods. Subjects are evaluated consecutively, including questionnaires, anthropometry, and vital signs, gynecological examination, modified Ferriman-Gallway (mF-G) scoring, pelvic ultrasound, and blood sampling. For PCOS diagnosis the investigators use the Rotterdam (2003) criteria. Serum samples are analyzed for total testosterone (TT) using LC-MS/MS. DHEAS, sex hormone-binding globulin (SHBG), prolactin, TSH, and 17-OHP are assessed by ELISA. Free Androgen Index (FAI) is calculated (i.e. [TT/SHBG] x 100). The upper normal limit (UNL) for the mF-G score is determined using a 2k-cluster analysis in the total study population. The upper normal limits (UNL) for TT, FAI, and DHEAS are determined from the 98th percentiles for these parameters in )women, identified as the "super-controls". Pelvic ultrasound (U/S) is performed by 3 experienced specialists with the appropriate intra/inter-observer variations, using Mindray М7 (MINDRAY, China), a transvaginal probe (5,0-8,0 МHz) or transabdominal probe (2,5-5,0 MHz). Ovarian volume is determined by the following formula: length x width x height x 0,523.