Risk of type 2 diabetes is increased in nonobese women with polycystic ovary syndrome: the National Health Insurance Service-National Sample Cohort Study.

Objective To investigate the relationship between polycystic ovary syndrome (PCOS) and type 2 diabetes mellitus (T2DM) in Korean women. Design Longitudinal case-control study. Setting Not applicable. Patient(s) PCOS patients aged 15 to 44 years (n = 1,136) and control individuals (n = 5,675), matched 1:5 by age group, income, and region of residence. Intervention(s) Not applicable. Main Outcome Measure(s) The occurrence of T2DM. Result(s) In the PCOS and control groups, 15.7% and 14.4%, respectively, were obese (body mass index ≥25 kg/m2). The incidence rate of T2DM was 15.84/1,000 and 5.80/1,000 person-years in the PCOS and control groups, respectively. The unadjusted hazard ratio (HR) of T2DM in women with PCOS was 2.6-fold higher than that in control individuals. Women with PCOS still had a higher HR of T2DM than did control individuals after adjustment for body mass index, family history of T2DM, physical exercise level, and total cholesterol. PCOS was significantly associated with T2DM in women both with and without obesity. Conclusion(s) PCOS is independently associated with an increased incidence of T2DM in both obese and nonobese women. Screening for T2DM should be considered for both obese and nonobese women with PCOS in Korea.