A COMPARATIVE STUDY OF POLYCYSTIC OVARY SYNDROME (PCOS) AMONGST CAUCASIAN SOUTH ASIAN WOMEN

Abstract

Polycystic ovaries are reported to be commoner in British Asians than among white Europeans. Insulin resistance (IR) is central to the pathogenesis of PCOS. Type 2 diabetes is commoner in South Asians. Objective: To determine any ethic difference in clinical, biochemical and selected genetic characteristics of PCOS in South Asians versus Caucasians. Patients and Design: Cross-sectional observational study of consecutive women with PCOS; UK based - 47 British Asian (BA), 40 Caucasian c women with PCOS and controls; 11 BA and 22C; Sri Lanka based - 80 Lankan women with PCOS (SL) and 45 controls. Methods: Clinical symptoms, anthropometric measurements, degree of acne, hirsutism and acanthosis nigricans; fasting blood glucose, plasma insulin, lipids, testosterone, and sex hormone binding globulin (SHBG), homocysteine, inhibin B and follistatin; DNA analysis for polymorphisms of Insulin VNTR of all subjects and FSH á gene in the British subjects were performed. Controls: Unrelated women without PCOS from matching ethnic background were studied at the same centres. Inter-laboratory biochemical correlation was performed. Results: CLINICAL FEATURES, INSULIN RESISTANCE PLASMA LIPIDS: (British Asian vs. Caucasian PCOS) - BA presented at a significantly younger age with similar BMI and waist:hip ratios (WHR). BA had oligomenorrhoea at a younger age, significantly greater hirsutism, and significantly greater prevalence of acne and acanthosis nigricans. Fasting insulin was significantly greater, insulin sensitivity (QUICKI) significantly less and SHBG significantly lower among BA PCOS. (Lankan vs. British Asian PCOS) - SL were of similar age to BA, had lower BMI but similar WHR. Age of onset of oligomenorrhoea and hirsutism were similar; had a lower prevalence of acne and more acanthosis nigricans. 6 had hypertension and 7.5 type 2 diabetes. Fasting blood glucose was higher in SL than BA, and of statistical significance. PLASMA HOMOCYSTEINE (Hcy) Was significantly higher in all women with PCOS compared with ethnically matched controls. SL PCOS had significantly greater Hcy than others, which correlated positively with fasting insulin and negatively with QUICKI. SERUM INHIBIN B AND FOLLISTATIN Follistatin in SL PCOS was significantly greater than others and correlated significantly with plasma insulin. Inhibin B concentrations in PCOS did not show an ethnic variation. INSULIN VNTR CLASS III ALLELE Had significantly greater frequency among C when compared with British Asian and Lanka PCOS, but showed no significant ethnic variation in the control groups. Its frequency in Asian PCOS did not correlate with their greater metabolic derangement. FSH á GENE ACCL POLYMORPHISM Showed similar degree of prevalence among British Asian and Caucasian PCOS groups, although among controls the Caucasians had a significantly lower prevalence Conclusions: 1) British Asians with PCOS have a similar degree of obesity, but more severe symptoms of hyperandrogenism, menstrual irregularity, greater fasting insulin and insulin resistance at a younger age than Caucasians with PCOS. 2) Indigenous Lankan PCOS subjects have a similar degree of hyperandrogenism, menstrual irregularity and central obesity despite a lower BMI, but significantly greater insulin resistance than age matched British Asians with PCOS. 3) Plasma bomocysteine is significantly greater in PCOS than ethnically matched controls and correlates with the ethnic variation of insulin resistance in Lankan, British Asian and Caucasian women with PCOS. 4) Follistatin is significantly greater in Lankan PCOS than other ethnic groups and correlates with insulin resistance, while inhibin B concentrations show no ethnic variation. 5) Insulin VNTR polymorphism class III allele is less prevalent among British Asian and Lankan PCOS women compared to Caucasian PCOS. 6) FSH á gene Accl polymorphism shows no ethnic variation in PCOS