A comparison of anthropometric indicators in predicting the incidence of diabetes and intermediate hyperglycaemia in Finland: a 22-year observational study

Background: Given the rising global prevalence of obesity and its strong association with type 2 diabetes, this study aims to evaluate the comparative effectiveness of various anthropometric indicators in predicting the incidence of type 2 diabetes and intermediate hyperglycaemia (IH) over a 22-year period. Due to the limitations of body mass index as a predictive marker, the study assesses alternative metrics, including waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), waist circumference (WC), and relative fat mass (RFM), to determine their predictive power for type 2 diabetes and intermediate hyperglycaemia. Methods: The cohort comprised 1168 adults (aged ≥ 50 years) from Savitaipale, Finland. Data collection included clinical and laboratory assessments and questionnaires at baseline and at the 10-, and 22-year follow-ups. The incidence of type 2 diabetes and IH was assessed via a 2-h oral glucose tolerance test and health care registry data. Receiver operating characteristic (ROC) curves and area under the curve (AUC) metrics were used to evaluate the predictive power of each indicator, stratified by sex. Results: WHR had the highest predictive accuracy for type 2 diabetes in men (AUC = 0.70), whereas RFM and WHtR were equally predictive in women (AUC = 0.68). For IH, RFM and WHR were most predictive in men, and WHtR in women. Combining multiple indicators improved the sensitivity of type 2 diabetes prediction. Conclusions: Alternative anthropometric indicators offer comparable predictive value and show potential for individualised type 2 diabetes and IH risk assessment. Sex-specific cutoffs and a multi-indicator approach could be used to improve screening and early intervention strategies, potentially improving public health management of diabetes risk.