Comparison of grip strength measurements for predicting all-cause mortality among adults aged 20+ years from the NHANES 2011–2014

Little is known about the optimal measure of handgrip strength for predicting all-cause mortality and whether this association is modified by age or sex. We used data from the 2011-2014 National Health and Nutrition Examination Survey (NHANES), 9,583 adults aged ≥ 20 years were included. Equal-length grip strength was measured using a digital handheld Takei dynamometer. We defined five measurements of grip strength, i.e., the average of handgrip strength (HGS), maximum of grip strength (MGS), HGS/body mass index (BMI), HGS/height (HT)², and MGS/weight, and three indicators of low grip strength, namely, low reference grip strength, lowest 20% grip strength, and low grip strength in sarcopenia. Information on deaths were obtained through linkage to National Death Index (NDI). Cox regression was used to assess the association of grip strength with mortality risk. HGS, MGS, HGS/BMI, HGS/HT², and MGS/weight were all inversely associated with all-cause mortality, with HGS or HGS/HT² (the area under the curve (AUC) = 0.714) being the optimal predictor of mortality, followed by MGS (AUC = 0.712). Participants with low grip strength showed increased risk of mortality regardless of which indicator was used, and the highest effect size was seen for lowest 20% grip strength group (hazard ratio (HR) = 2.20 for men, 2.52 for women). The above-mentioned correlations were consistently found in people of different ages and sexes. This study suggests the simplest measure of absolute grip strength (HGS, MGS) was the optimal index for predicting all-cause mortality, followed by HGS/HT². Keeping an adequate level of handgrip strength may be beneficial to reduce the risk of mortality.