Age- and Sex-Specific Relative Handgrip Strength Thresholds Associated with Prevalent Metabolic Syndrome in Korean Adults

PURPOSE: Absolute handgrip strength is influenced by body size, whereas relative handgrip strength may better reflect cardiometabolic risk.This study derived age-and sex-specific exploratory relative handgrip strength thresholds for identifying metabolic syndrome in Korean adults and examined whether lower threshold-defined categories were associated with metabolic syndrome after adjustment for selected covariates, including estimated cardiorespiratory fitness. METHODS:This cross-sectional analysis included 3,307 adults (1,427 men and 1,880 women) from the Korea Institute of Sport Science Fitness Standards study.Relative handgrip strength was calculated as absolute handgrip strength divided by body mass index.Metabolic syndrome was defined using modified National Cholesterol Education Program Adult Treatment Panel III criteria with Korean waist circumference cutoffs.Receiver operating characteristic analyses compared absolute and relative handgrip strength and derived sensitivityand specificity-oriented thresholds in participants aged 50 years or younger and older than 50 years. RESULTS:Relative handgrip strength discriminated prevalent metabolic syndrome better than absolute handgrip strength in men (area under the curve, 0.612 compared with 0.533) and women (0.717 compared with 0.588).Thresholds were 1.85 and 1.57 kg/body mass index in younger men, 1.64 and 1.36 in older men, 1.21 and 1.01 in younger women, and 1.02 and 0.84 in older women.In fully adjusted exploratory models, odds ratios for metabolic syndrome were 1.916 and 2.209 in men and 1.786 and 2.077 in women for intermediate and low relative handgrip strength groups. CONCLUSIONS:Relative handgrip strength showed modest discrimination in men and moderate discrimination in women.Cohortderived thresholds may support exploratory exercise-health screening, but external validation is needed.