Handgrip Strength Asymmetry and Weakness Are Associated with Lower Cognitive Function: A Panel Study

BACKGROUND/OBJECTIVES: Examining handgrip strength (HGS) asymmetry and weakness together may extend the predictive capacity of HGS for capturing possible health problems such as cognitive impairment. The purpose of this study was to determine the associations of HGS asymmetry and weakness on lower cognitive functioning in a national sample of aging Americans. DESIGN: Longitudinal panel. SETTING: Participant residences. PARTICIPANTS: The analytic sample included 17,163 Americans aged 65.0 years (standard deviation = 10.1 years) who participated in the 2006 to 2016 waves of the Health and Retirement Study (HRS). MEASUREMENTS: A handgrip dynamometer was used to measure HGS; weakness was defined as HGS below 26 kg (men) or below 16 kg (women). Persons with HGS above 10% stronger on either hand were considered as having any HGS asymmetry. Those with HGS that was more than 10% stronger on their dominant or nondominant hand were considered as having dominant or nondominant HGS asymmetry, respectively. The Telephone Interview of Cognitive Status determined lower cognitive functioning (/=65 years). Covariate-adjusted linear mixed-effects models analyzed the associations of each HGS asymmetry and weakness group on lower cognitive functioning. RESULTS: Relative to those with symmetric HGS and no weakness, each HGS asymmetry and weakness group had greater odds for lower cognitive functioning: 1.15 (95% confidence interval [CI] = 1.03-1.27) for any HGS asymmetry alone, 1.64 (95% CI = 1.21-2.23) for weakness alone, and 1.95 (95% CI = 1.51-2.53) for any HGS asymmetry and weakness. Each HGS asymmetry dominance and weakness group also had greater odds for lower cognitive functioning: 1.12 (95% CI = 1.01-1.25) for asymmetric dominant HGS alone, 1.27 (95% CI = 1.05-1.53) for asymmetric nondominant HGS alone, 1.64 (95% CI = 1.21-2.23) for weakness alone, 1.89 (95% CI = 1.39-2.57) for weakness and asymmetric dominant HGS, and 2.10 (95% CI = 1.37-3.20) for weakness and asymmetric nondominant HGS. CONCLUSION: The presence of both HGS asymmetry and weakness may predict accelerated declines in cognitive functioning.