Diverse impacts of aging on insulin resistance in lean and obese women with polycystic ovary syndrome: evidence from 1345 women with the syndrome

Abstract

Background: Polycystic ovary syndrome (PCOS) represents a moving spectrum of hormonal to metabolic abnormalities, as women with the syndrome are aging. Hormonal abnormalities, anovulation, and hyperandrogenic signs were predominant during the early years of PCOS and fade away with the years. Metabolic abnormalities and insulin resistance (IR) remain throughout the PCOS life cycle; however, it is unclear as to how they change, as women with the syndrome are aging.

Objective: To evaluate the changes in IR and its associations with clinical, biochemical, hormonal, and ultrasound findings in a large cohort of women with PCOS and controls, as they are aging.

Design: A cross-sectional study was carried out to evaluate the diverse impacts of aging on IR.

Setting: An outpatient clinic was chosen for the study.

Participants: A total of 1345 women with PCOS (Rotterdam criteria) and 302 controls of Caucasian origin and Greek ethnicity comprised the study group.

Main outcome and measures: The impact of age on IR, as calculated using homeostasis model assessment of IR (HOMA-IR) index, and several PCOS characteristics were evaluated.

Results: In PCOS, age (-0.045±0.008) was negatively, and BMI positively (0.18±0.007) associated with HOMA-IR (R(2)=0.36). When data were stratified with regard to the BMI status, a negative association of age with HOMA-IR was found in lean, normal, and overweight patients (r: -0.266, -0.233, -0.192, P<0.001), which was neutralized in obese patients (r: -0.009, P: NS). Free androgen index and BMI were positively associated with HOMA-IR in all age quartiles. When mean HOMA-IR values were plotted according to BMI subgroups at different age quartiles, a significant gradual decrease in HOMA-IR was observed in normal (P<0.001) and overweight (P: 0.004), but not obese, women (P: 0.202) across age quartiles.

Conclusions: Aging increases IR in obese but not in lean and overweight women with PCOS. As BMI and androgens are positively associated with HOMA-IR and androgens decline through time, it appears that if women with PCOS do not become obese they may exhibit a better metabolic profile during their reproductive years.