Handgrip Strength Asymmetry Is Associated With Future Accumulating Morbidities In Older Americans

Abstract

Functional asymmetries are an often-observed form of poor muscle function during aging that is typically not evaluated in handgrip strength (HGS) protocols. Examining such asymmetries in older populations may help in identifying persons at risk for future morbidities linked to poor muscle function. PURPOSE: We sought to determine the association between asymmetric HGS and future accumulating morbidities in older Americans. METHODS: The analytic sample included 18,506 participants aged 65.0 ± 10.2 years from the 2006-2016 waves of the Health and Retirement Study. HGS was collected on each hand with a handgrip dynamometer. The highest HGS on each hand was used for determining HGS asymmetry ratio: (non-dominant HGS/dominant HGS). Persons with HGS asymmetry ratio < 1.0 had their ratio inverted to make all ratios ≥1.0. Participants were categorized into asymmetry groups based on their inverted HGS asymmetry ratio: 1) 0.0%-10.0%, 2) 10.1%-20.0%, 3) 20.1%-30.0%, and 4) >30.0%. Each person reported the presence of healthcare provider diagnosed morbidities: hypertension, diabetes, cancer, chronic lung disease, cardiovascular disease, stroke, psychiatric problems, and arthritis. Separate covariate-adjusted ordinal generalized estimating equations were used for the analyses. RESULTS: Every 0.10 (i.e., 10%) increase in HGS asymmetry ratio was associated with 1.21 (95% confidence interval (CI): 1.09-1.35) greater odds for future accumulating morbidities. Compared to those with HGS asymmetry 0.0%-10.0%, persons with wider asymmetry had greater odds for future accumulating morbidities: 1.07 (CI: 1.02-1.12) for HGS asymmetry 10.1%-20.0%, 1.09 (CI: 1.02-1.16) for HGS asymmetry at 20.1%-30.0%, and 1.22 (CI: 1.11-1.35) for HGS asymmetry >30.0%. CONCLUSIONS: Functional asymmetries between limbs, as another form of muscle dysfunction, are associated with future morbidity accumulation in during aging. Moreover, wider strength asymmetries between limbs may especially elevate risk for future morbidity accumulation. We recommend that health practitioners evaluate HGS asymmetry as a simple screening mode for helping to determine poor muscle function and future morbidity risk.