Racial and ethnic differences in the prevalence of metabolic syndrome and its components of metabolic syndrome in women with polycystic ovary syndrome: a regional cross-sectional study

BACKGROUND: Polycystic ovary syndrome is a heterogeneous disorder and its presentation varies with race and ethnicity. Reproductive-age women with polycystic ovary syndrome are at increased risk of metabolic syndrome; however, it is not clear if prevalence of metabolic syndrome and clustering of its components differs based on race and ethnicity. Moreover, the majority of these women do not undergo routine screening for metabolic syndrome. OBJECTIVE: We sought to compare the prevalence of metabolic syndrome and clustering of its components in women with polycystic ovary syndrome in the United States with women in India, Brazil, Finland, and Norway. STUDY DESIGN: This is a cross-sectional study performed in 1089 women with polycystic ovary syndrome from 1999 through 2016 in 5 outpatient clinics in the United States, India, Brazil, Finland, and Norway. Polycystic ovary syndrome was defined by the Rotterdam criteria. Main outcome measures were: metabolic syndrome prevalence, blood pressure, body mass index, fasting high-density lipoprotein cholesterol, fasting triglycerides, and fasting glucose. Data from all sites were reevaluated for appropriate application of diagnostic criteria for polycystic ovary syndrome, identification of polycystic ovary syndrome phenotype, and complete metabolic workup. The US White women with polycystic ovary syndrome were used as the referent group. Logistic regression models were used to evaluate associations between race and metabolic syndrome prevalence and its components and to adjust for potential confounders, including age and body mass index. RESULTS: The median age of the entire cohort was 28 years. Women from India had the highest mean Ferriman-Gallwey score for clinical hyperandrogenism (15.6 +/- 6.5, P < .001). The age-adjusted odds ratio for metabolic syndrome was highest in US Black women at 4.52 (95% confidence interval, 2.46-8.35) compared with US White women. When adjusted for age and body mass index, the prevalence was similar in the 2 groups. Significantly more Black women met body mass index and blood pressure criteria (P < .001), and fewer met fasting triglycerides criteria (P < .05). The age- and body mass index-adjusted prevalence of metabolic syndrome was highest in Indian women (odds ratio, 6.53; 95% confidence interval, 3.47-12.30) with abnormalities in glucose and fasting high-density lipoprotein cholesterol criterion and in Norwegian women (odds ratio, 2.16; 95% confidence interval, 1.17-3.98) with abnormalities in blood pressure, glucose, and fasting high-density lipoprotein cholesterol criterion. The Brazilian and Finnish cohorts had similar prevalence of metabolic syndrome and its components compared to US White women. CONCLUSION: Despite a unifying diagnosis of polycystic ovary syndrome, there are significant differences in the prevalence of metabolic syndrome and clustering of its components based on race and ethnicity, which may reflect contributions from both racial and environmental factors. Our findings indicate the prevalence of metabolic syndrome components varies in women with polycystic ovary syndrome, such that compared to White women from the United States, Black US women had the highest prevalence, whereas women from India and Norway had a higher prevalence of metabolic syndrome independent of obesity. The differences in clustering of components of metabolic syndrome based on ethnicity highlight the need to routinely perform complete metabolic screening to identify specific targets for cardiovascular risk reduction strategies in these reproductive-age women.