Question special

PCOS is not a disease (Speroff); it is a set of characteristics. The set and the definitions are changing every some years or so by different groups that change also in time and person. The predominant biological feature is (WHO type II) anovulation, in eg Caucasians also obesity.
Lim et al (Human Reprod Update 2012;18:618) stated that The proportion of women with PCOS who were overweight and obese had a pooled estimated prevalence of 61% (95% CI: 54–68%)., whereas Chen et al reported BMI in both groups respectively 23.8±3.8 and 23.9±3.6. Lim et al concluded also that “The Caucasian women with PCOS had a greater increase in obesity prevalence than the Asian women with PCOS compared with women without PCOS ”. PCOS, is a very heterogeneous entity and the finding of Lim et al is an indication of low generalizability of this study. May I refer to the study by Cai et al PLoS One 2014:22;9(1):e86972: “Our present meta-analysis indicated that FTO rs9939609 polymorphism (or its proxy) might not be associated with risk of PCOS in overall population. However, in East Asians, there might be a direct association between FTO variant and PCOS risk, which is independent of BMI (adiposity).”