The risk of coronary heart disease (CHD) is lower in women than men. This has been attributed to differences in sex hormones, insulin sensitivity, and environmental factors. Women with Polycystic Ovary syndrome have characteristics, including anovulation, hyperandrogenism and insulin resistance, which suggests a male risk factor profile. The study tests the hypothesis that women with PCOS are at greater risk of coronary heart disease than non-PCOS women. When the study was initiated in 1991, there were few data available on long-term followup of women with PCOS.