Considering the Confounding Effect of Obesity on Long-term Health Consequences of PCOS
The prevalence of overweightness has continued to increase in the United States with greater than 36% of U.S. adults estimated to be obese. The relationship between PCOS and obesity is complex. In the United States, obesity has been reported to affect 30 to 75% of women with PCOS,[12,13] a prevalence higher than in European patients.[14,15] A systematic review and meta-analysis by Lim et al concluded that there was a higher prevalence of overweight and obese women among those with PCOS compared with controls. Furthermore, white women were more likely to be obese than Asian women with PCOS. However, these results are confounded by the fact that in most of the studies reviewed, patients were recruited from the clinical setting, with its attendant referral bias. In general, obese women are more likely to be referred for the evaluation for PCOS. However, in medically unbiased populations, the prevalence of obesity does not appear to be as high as it is in clinical populations.[9,17] Additionally, the prevalence of PCOS is relatively stable across the globe, when using the NIH criteria to define PCOS, despite variable population rates of obesity.
Obesity can exacerbate or foster other long-term morbidities including metabolic complications, risk of certain types of cancer from chronic unopposed estrogen, and can additionally lead to decreased quality of life (QOL) and low self-esteem, which can manifest as a variety of mood disorders (see below). Obese women with PCOS may represent a more severe phenotype, with greater degrees of insulin resistance, hyperinsulinemia, metabolic dysfunction, and hyperandrogenism. Multiple studies have concluded that there is a greater degree of insulin resistance in obese compared with lean women with PCOS.[18,19] Consequently, the concomitant presence of obesity will be associated with a further increase in the long-term risk for metabolic dysfunction in women with PCOS.
Semin Reprod Med. 2017;35(3):271-281. © 2017 Thieme Medical Publishers