Abstract
A bi‑directional relationship exists between obesity and polycystic ovary syndrome (PCOS). Although most of the patients with PCOS are obese, normal-weight patients still account for a certain proportion of PCOS who have lesser degrees of insulin resistance and fewer metabolic risk factors. This study was conducted to compare the clinical, metabolic, and endocrine parameters of the two categories of PCOS: lean and obese PCOS. We evaluated 523 women with PCOS attending the Endocrinology outpatient department of a tertiary hospital in Bangladesh. PCOS patients with body mass index (BMI) <23 kg/m2 were categorized as lean PCOS and those with BMI ≥23 kg/m2 as obese PCOS. Out of 523 women with PCOS studied, the frequencies of lean- and obese PCOS were 23.3% and 76.7%, respectively. Age, systolic blood pressure (BP), diastolic BP, fasting plasma glucose, plasma glucose 2-hour after oral glucose tolerance test, serum triglyceride, total cholesterol, low-density lipoprotein cholesterol, total testosterone, and thyroid-stimulating hormone were higher in obese PCOS group; serum prolactin was higher in the lean PCOS group; modified Ferriman-Gallwey score and high-density lipoprotein cholesterol were similar in the two groups. Acanthosis nigricans (89.3% vs. 45.9%), prediabetes (24.4% vs. 13.1%), diabetes (6.7% vs. 1.6%), pre-hypertension (22.2% vs. 9.8%), hypertension (8.7% vs. 0.8%), metabolic syndrome (61.3% vs. 14.8%), and biochemical hyperandrogenism (27.7% vs. 11.5%) were more frequent in the obese group than the lean group. The two groups had similar frequencies of menstrual irregularity, hirsutism, a family member with type 2 diabetes, and dyslipidemia. Though metabolic abnormalities are more frequently observed when obesity is associated with PCOS, both lean and obese have adverse metabolic consequences. All patients with PCOS should be screened for metabolic abnormalities irrespective of BMI category.