Obesity, rather than menstrual cycle pattern or follicle cohort size, determines hyperinsulinaemia, dyslipidaemia and hypertension in ageing women with polycystic ovary syndrome

OBJECTIVE: The aim of this study was to investigate if ageing women with polycystic ovary syndrome (PCOS) who gained regular menstrual cycles differed from women who continued to menstruate irregularly with regard to risk factors for developing diabetes mellitus and atherosclerosis. DESIGN AND PATIENTS: In the original study of a population of 346 PCOS patients, defined in the past as having oligo- or amenorrhoea and elevated LH concentrations, we had sent out a questionnaire to investigate changes in the pattern of their menstrual cycles while ageing. From this cohort of patients, a significantly older group of 53 women (mean age: 41.3 years, range: 33.3-49.4) who were not using oral contraceptives or other hormones visited the out-patient clinic. These women did not differ from the non-participating group in BMI, ethnic origin, the proportion with regular menstrual cycles by age group, parity or the use of clomiphene citrate or gonadotrophins in the past. MEASUREMENTS: A physical examination and a transvaginal ultrasound were performed. The size of the follicle cohort was determined by counting the number of small follicles in the ovaries. Thirty-four women were also willing to give two fasting blood samples for measuring their glucose, insulin and lipid status. RESULTS: Forty-one of the 53 (77.4%) women had a regular menstrual cycle (shorter than 6 weeks) and 12 (22.6%) had an irregular cycle (longer than 6 weeks). The body mass index (BMI), waist : hip ratio (WHR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and prevalence of diabetes (1.9%) and hypertension (11.3%) did not differ between the two menstrual cycle groups. Also, the fasting glucose, insulin, glucose/insulin ratio, total cholesterol, HDL-c, and LDL-c concentrations did not show any significant difference between the two groups. Instead, these parameters all were significantly higher in women with a BMI > 27 kg/m² compared to women with a BMI ≤ 27 kg/m². Regularly menstruating PCOS women were older (P < 0.01), showed less follicles in their ovaries (n = 48, P < 0.01) and had lower androgens (n = 34, P < 0.05) than the irregularly menstruating women. Logistic regression analysis showed a second significant influence, after age, of the BMI on the menstrual cycle pattern (age, P < 0.01; BMI, P < 0.05). If age was excluded from the analysis, only the follicle count significantly predicted the menstrual cycle pattern (P < 0.02). CONCLUSIONS: We conclude that hyperinsulinaemia, dyslipidaemia and hypertension in our population of ageing women with polycystic ovary syndrome are not related to the menstrual cycle pattern but rather to obesity. Age and the size of the follicle cohort are the main factors determining the menstrual cycle pattern in ageing women with polycystic ovary syndrome, although an association with the BMI was also found.