Subjects

A total of 28 adult (18-35 years) white women diagnosed with PCOS according to the Rotterdam criteria were considered eligible for the study after secondary causes of hyperandrogenism (hyperprolactinemia, thyroid and adrenal disorders) were excluded.

Subjects were divided into 2 groups according to their body mass index (BMI) (weight in kg/height in m ² ): 16 were lean (group A, BMI <25); 12 were overweight (group B, BMI >25). All patients were oligomenorrheic (cycle length ≥35 days <6 months).

All subjects were nonsmokers, did not take regular intense exercise, and did not receive hormonal therapy for at least 6 months prior to the study. In addition, women with diabetes, renal or hepatic illness, and folic acid and vitamin B ₁₂ deficiencies were excluded from the study. Further exclusion criteria were: endometriosis, ovarian functional cyst, unilateral ovarian resection, or ovariectomy.

Pregnancy test results were negative in all patients before the enrollment in the study. Finally, all participants were instructed to avoid any intense exercise and to refrain from intake of caffeine-containing beverages in the 24 hours antecedent the study.

The study protocol was in accordance with the Helsinki II declaration and was approved by the hospital research review committee. The study was conducted, between October 2006 and October 2007, in the Department of Obstetrics and Gynecology of the Bologna University School of Medicine. Women participated in the study after having signed an informed consent.

Study design

After the first screening evaluation, participants were assessed, in the early follicular phase (cycle days 3-5), after an overnight fast, with a detailed history and medical examination. Standing height and weight were measured and the mean BMI was calculated.

Blood pressure was taken during the screening evaluation by the cuff technique with a mercury sphygmomanometer applied to the nondominant arm. The measurement was repeated after 10 minutes and the arithmetic mean of the 2 measurements was used for statistical analysis.

Both lean and overweight patients were invited to fill in a meal diary in which they had to record everything they ate for 7 days.

Fasting blood samples were drawn for testing biochemical parameters. Patients were submitted to an ultrasonographic (US) and color Doppler analysis of brachial artery flow-mediated vasodilatation.

Since all patients were seeking OC, after the baseline assessment, they were prescribed a monophasic OC containing 30 μg of EE plus 3 mg of DRSP (Yasmin; Schering AG, Berlin, Germany) (21 days/mo) for 6 cycles. The meal diary showed an excess of caloric intake (≥2200/day) in all overweight subjects, therefore they were also given, in association with the OC, a 1700-kcal/day diet and were invited to exercise at least 1 hour 3 times a week although subjects were not asked to record their activity. Since lean patients did not show any excess in caloric intake and they all exercised regularly, no recommendation of lifestyle changes was made.

At the end of the sixth cycle all patients underwent the same evaluation as at baseline. The meal diaries were collected from the overweight subjects.

Brachial artery flow-mediated vasodilatation

A high-resolution US transducer (7-10 MHz multifrequency linear-array transducer, Aspen; Acuson-Siemens, Milan, Italy) was placed over the brachial artery to measure its diameter before and after reactive hyperemia. A Doppler analysis of brachial artery (Aspen color Doppler) was performed and the pulsality index (PI)s registered at baseline and just after US measurements of brachial artery. We recently observed that the brachial artery diameter has anatomic characteristics correlated with the BMI and the specific body variables of the patients (unpublished data). Therefore, in this study we did not evaluate statistically the absolute differences in brachial artery diameter, but we analyzed its US and Doppler postischemic percentage of variations. Brachial artery flow-mediated vasodilatation was evaluated by a single examiner (C.B.).

Assays

Peripheral blood flow was obtained from all patients between 8:00 am and 11:00 am , after an overnight fast, on the same day that US and Doppler examinations took place.

An aliquot of peripheral blood was immediately centrifuged and serum stored at –70° until assays. Leptin and ET were assayed at Modena-Reggio Emilia University (F.F.) as previously described. Plasma Hcy concentration (μmol/L) was determined as previously described.

Plasma glucose levels were determined by the glucose-oxidize method on a glucose analyzer (Beckman, Fullerton, CA), and plasma insulin was determined using an immunoradiometric assay (Biosource Europe SA, Nivelles, Belgium). The definition for normal fasting glucose (<110 mg/dL), impaired fasting glucose (110-126 mg/dL), and diabetes (>126 mg/dL) were based on the established American Diabetes Association criteria. The homeostatic model assessment estimates for insulin resistance (HOMA-IR) and fasting glucose-insulin ratio were derived as estimates of insulin sensitivity. HOMA-IR was computed using the following formula: fasting insulin (μU/mL) × fasting glucose (mmol/L)/22.5. Fasting glucose-insulin ratio was calculated using: glucose (mg/dL)/insulin (μU/mL).

Use of statistics

Statistical analysis (SPSS 11.5 software; SPSS Inc, Chicago, IL) was performed using the 1-way analysis of variance test. For repeated measures we used the Wilcoxon test. The relationship between the parameters analyzed was assessed using the stepwise linear regression method. A P value < .05 was considered as statistically significant. Data are presented as mean ± SD, unless otherwise indicated. The statistical analysis was performed by a single researcher (N.P.).