The prevalence of Type 2 diabetes is not increased in normal-weight women with PCOS

Abstract

Study question: Is oral glucose tolerance test (OGTT) needed in all women with polycystic ovary syndrome (PCOS)?

Summary qnswer: OGTT is not routinely needed in women with PCOS and BMI < 25 kg/m2.

What is known already: PCOS is associated with insulin resistance and increased prevalence of prediabetes and Type 2 diabetes (T2D) which is closely linked to obesity and possibly age, ethnicity and PCOS phenotype. Several guidelines recommend OGTT upon diagnosis of PCOS and during follow-up.

Study design, size, duration: A Nordic cross-sectional study including 876 women.

Participants/materials, setting, methods: The 876 Nordic women with PCOS, aged 14-57 years, were examined for T2D and prediabetes (impaired glucose tolerance [IGT] or impaired fasting glucose (IFG) by OGTT.

Main result and the role of chance: Of all study subjects 3% (23/876) had T2D, 23% (204/876) prediabetes and 74% (649/876) had normal glucose tolerance (NGT). Increased BMI and waist circumference were significantly (P < 0.001) associated with prevalence of prediabetes and T2D. No normal-weight woman (BMI < 25 kg/m2) was diagnosed with T2D. The prevalence of BMI ≥ 25 kg/m2 was 66% (578/ 876). 91% of women (21/23) with T2D had BMI ≥ 30 kg/m2. Testosterone levels and PCOS phenotype did not predict 2-h glucose levels during OGTT after adjustment for BMI and age.

Limitations, reasons for caution: The present study included cross-sectional data and prospective studies are needed to confirm our results. These results may not apply to populations of other ethnic origin.

Wider implications of the findings: Routine OGTT may not be indicated in normal-weight women with PCOS.

Study funding/competing interest(s): None.

Trial registration number: N/A.

Keywords: BMI; Polycystic ovary syndrome; Type 2 diabetes; lean; oral glucose tolerance test.