Among 1,124 U.S. adults aged 40-59 from NHANES (508 for development, 616 for temporal validation), adding DXA body fat percentage and visceral fat to age, sex, BMI and waist circumference raised the logistic-regression AUC by about 0.021 in both cohorts. Adding absolute handgrip strength on top of muscle mass moved AUC by -0.005 and +0.005, with every interval spanning zero across all 12 comparisons spanning algorithms, outcome definitions and cohorts. Calibration and net benefit did not improve.
Grip strength is often promoted as a cheap vital sign, and large cohorts link weak grip to mortality and cardiovascular events. This analysis does not contradict that. It tests a narrower question: whether grip strength sharpens a snapshot of concurrent metabolic abnormalities (blood pressure, glucose, triglycerides, HDL) once body composition is already measured. The answer is no, though visceral and total fat carry more of that signal. Important caveats: the outcome is cross-sectional, so it says nothing about grip's value for predicting future disease or death; the samples are modest, which limits power to detect small gains; and most clinics lack DXA, so grip may still be useful where body composition is unavailable. This is a preprint that has not been peer reviewed, and the findings could shift on review. The evidence is confirmatory and incremental: grip strength remains worth building as a functional capacity marker, but it should not be counted on to flag metabolic dysfunction beyond waist and fat measures.