Aims

Early detection of diabetes is important for the prevention of diabetic complications. The best adiposity index for indicating Type 2 diabetes mellitus remains unclear. We aimed to identify the optimal adiposity measure among BMI, waist circumference, waist–hip ratio and waist-to-height ratio to indicate undiagnosed Type 2 diabetes and impaired fasting glucose in Chinese adults.

Methods

A total of 7567 participants aged 20–79 years were included in this study. Impaired fasting glucose was defined as a fasting plasma glucose level of 6.1–6.9 mmol/l in participants without diabetes. Undiagnosed Type 2 diabetes was identified as fasting plasma glucose ≥ 7.0 mmol/l when neither a history of diabetes nor use of hypoglycaemic drugs was present. Body weight, height, waist and hip circumferences were measured following standard procedures. Data were analysed using logistic regression and areas under the receiver operating characteristic curves.

Results

Of the 7567 participants, 536 were defined as having impaired fasting glucose and 690 were patients with Type 2 diabetes, including 290 (3.8%) persons with undiagnosed diabetes. In multivariate logistic regression, the odds ratios of waist-to-height ratio (≥ 0.5) were stronger than BMI (≥ 24 kg/m²), waist circumference (≥ 85 cm in men and ≥ 80 cm in women) and waist–hip ratio (≥ 0.85) for undiagnosed Type 2 diabetes and impaired fasting glucose. Among the four indices, waist-to-height ratio ≥ 0.5 showed the largest area under the receiver operating characteristic curve for diagnosing undiagnosed Type 2 diabetes (0.725, 95% CI 0.693–0.756) and impaired fasting glucose (0.662, 95% CI 0.638–0.687).

Conclusions

By comparison with BMI, waist circumference and waist–hip ratio, waist-to-height ratio ≥ 0.5 may be the best indicator for undiagnosed Type 2 diabetes and impaired fasting glucose.