<qa>  What is the onset of PCOS usually at the time of puberty?Polycystic ovary syndrome PCOS affects 5-10 of women in the United States. Its onset is usually at the time of puberty with manifestations of menstrual irregularity, hirsutism, and obesity. Women with PCOS suffer at an early stage of adulthood from all of the components of the metabolic syndrome, a syndrome that typically has its peak in mid-life in other subject populations. Women with PCOS are more insulin resistant than weight-matched control women and have exceptionally high rates of early-onset impaired glucose tolerance and type 2 diabetes, as well as a substantially elevated risk for hypertension, dyslipidemia, coronary, and other vascular diseases. While recent evidence indicates that the prevalence of sleep-disordered breathing SDB is 30-40 fold higher in PCOS than in weight-matched control women, the possible role of SDB in causing the increased metabolic and cardiovascular risks of PCOS has not been evaluated. The overall objective of the proposed study is to analyze the direction of causality between sleep disturbances and markers of the metabolic syndrome in PCOS. 