Handgrip strength cut-off points for identifying French adults at risk of type 2 diabetes

To identify cut-off points for handgrip strength (HGS) detecting T2D risk among adults in France, and to examine the relationships between absolute and relative HGS and the incidence of T2D.

Data from 18,519 adults (5096 men) in the NutriNet-Santé cohort, were analyzed. HGS was measured using dynamometry on both hands. Nine indicators were derived, including absolute values and those relative to body weight and BMI. Receiver Operating Characteristic curves and cubic splines were used to assess predictive performance, as well as cut-off points for HGS that maximize this performance. Cox proportional hazards models were used to evaluate associations between reduced HGS and T2D.

Over 9.8 years, 329 incident T2D cases were validated. Absolute HGS showed not associated with T2D risk, whereas higher relative HGS was associated with lower risk (e.g. HR for HGS relative to body weight: 1.30, 95 % CI: 1.07-1.58). Relative HGS showed better discrimination (AUC 0.623-0.675) than absolute HGS (≤ 0.44). Optimal cut-offs were 0.446 kg/kg and 1.086 kg/kg/m² (dominant hand), and 0.397 kg/kg and 1.033 kg/kg/m² (non-dominant). Low relative HGS was associated with increased risk (HRs 1.42-1.68), consistent across sensitivity, sex, and age analyses.

Relative, but not absolute, handgrip strength is independently associated with T2D incidence and shows modest discriminative ability. Given its simplicity and cost-effectiveness, grip strength may be a useful screening tool in clinical and public health settings.