Association of body mass index with risk of prediabetes in Chinese adults: A population‐based cohort study

AIMS/INTRODUCTION: Overweight and obesity in adults are strongly associated with an increased risk of prediabetes, and this study set out to gain a better understanding of the optimal body mass index (BMI) range for assessing the risk of prediabetes in the Chinese population. MATERIALS AND METHODS: The cohort study included 100,309 Chinese adults who underwent health screening. Participants were divided into six groups based on the cut‐off point for BMI recommended by the World Health Organization (underweight: <18.5 kg/m(2), normal‐weight: 18.5–24.9 kg/m(2), pre‐obese: 25.0–29.9 kg/m(2), obese class I: 30.0–34.9 kg/m(2), obese class II: 35.0–39.9 kg/m(2), and obese class III ≥40 kg/m(2)). The association of BMI with prediabetes and the shape of the correlation were modeled using multivariate Cox regression and restricted cubic spline regression, respectively. RESULTS: In the multivariate Cox regression model, with normal weight as the control group, underweight people had a lower risk of developing prediabetes, whereas obese and pre‐obese people had a higher risk of prediabetes. Additionally, in the restricted cubic spline model, we found that the association of BMI with prediabetes follows a positive dose–response relationship, but does not conform to the pattern of obesity paradox. Among the general population in China, a BMI of 23.03 kg/m(2) might be a potential intervention threshold for prediabetes. CONCLUSIONS: The national cohort study found that the association of BMI with prediabetes follows a positive dose–response relationship, rather than a pattern of obesity paradox. For Chinese people with normal weight, more attention should be paid to glucose metabolism when BMI exceeds 23.03 kg/m(2).