Association Between Relative Grip Strength, Insulin Resistance, and Nonalcoholic Fatty Liver Disease Among Middle-Aged and Older Adults: A Prospective Cohort Study

<b><i>Introduction:</i></b> This study aims to investigate the combined association between insulin resistance (IR) levels, relative grip strength (RGS), and the incidence of nonalcoholic fatty liver disease (NAFLD), stratified by sex, using longitudinal data. <b><i>Methods:</i></b> The study included 1702 adult participants aged 51-88 years who completed surveys in both 2013-2014 and during a subsequent follow-up in 2019-2020. NAFLD was assessed using the hepatic steatosis index, and RGS was measured using the JAMA-5030J1 equipment (SAEHAN, Korea). To assess the interaction between RGS and IR levels and their impact on NAFLD risk, we employed a proportional hazards Cox regression model. Hazard ratios (HR) and 95% confidence intervals (95% CI) were calculated for NAFLD incidence. <b><i>Results:</i></b> After adjusting for various confounding variables, we observed a significant decrease in NAFLD risk in the middle RGS group (HR = 0.70, 95% CI = 0.53-0.93) and high RGS group (HR = 0.31, 95% CI = 0.22-0.44) compared to the low RGS group. In addition, significant sex differences were noted in the relationship between IR, RGS levels, and NAFLD incidence across different groups. <b><i>Conclusions:</i></b> This study highlights that higher RGS levels are independently associated with a reduced risk of developing NAFLD. Notably, RGS emerges as a predictive indicator for assessing NAFLD risk.