Examining the directional associations of handgrip strength asymmetry and cognitive function in American males and females.

BackgroundWhile low handgrip strength (HGS) and cognitive impairment could be bidirectionally associated through shared neurological systems, the role of HGS asymmetry for this directional association is not well-understood in males and females.ObjectiveThe purpose of this investigation was to determine the directional associations between HGS asymmetry and cognitive impairment in Americans by sex.MethodsThe analytical sample included 5298 male and 7070 female participants aged at least 50-years from the 2006-2018 waves of the Health and Retirement Study. HGS was measured with a handgrip dynamometer. The highest recorded HGS on both hands were included in the quantification of HGS asymmetry. Cognitive function was assessed with the Telephone Interview of Cognitive Status. Individual generalized estimating equations evaluated the directional associations of HGS asymmetry and impaired cognitive function.ResultsCategorical asymmetric HGS was associated with 1.25 (95% confidence interval (CI): 1.01-1.54) greater odds for future cognitive impairment in males. Every unit increase in continuous HGS asymmetry ratio was also associated with 1.37 (CI: 1.04-1.80) greater odds for future cognitive impairment in males. However, cognitive impairment, in males, was not significantly associated with future asymmetric HGS (odds ratio: 1.18; CI: 0.97-1.44). No significant directional associations between asymmetric HGS and impaired cognitive function were observed in females.ConclusionsAsymmetric HGS, as another marker of muscle dysfunction, may provide direction for the association between muscle and cognitive function, particularly in males. While more research is needed for examining the prognostic value of asymmetric HGS, including asymmetry is feasible in conventional HGS protocol guidelines.