The associations between handgrip strength asymmetry and future cognitive impairment in older adults

Abstract Background The incidence and prevalence of dementia continue to increase exponentially as people age. Finding a pre‐clinical marker to detect dementia early is paramount in clinical practice. There are few prospective studies evaluating handgrip strength, handgrip strength asymmetry, and their combination on cognitive impairment. This study aimed to investigate the association of handgrip strength and handgrip strength asymmetry with future global and specific cognitive domain impairment. Method This is a seven‐year prospective cohort study (Fig 1). We used data from the ongoing Taiwan Initiative of Geriatric Epidemiological Research (TIGER), wave 3 (2015‐2017) to wave 5 (2019‐2022), with wave 3 as the baseline (n = 446). Low handgrip strength was defined as the lowest tertile of sex‐specific handgrip strength. Handgrip strength asymmetry was defined as a handgrip strength ratio <0.85 or >1.15 (i.e., a 15% difference). The cognitive assessment included global and specific cognitive domains. Generalized linear mixed models were used to assess the association of handgrip strength asymmetry and cognitive performance adjusted for age, years of education, cigarette smoking, alcohol drinking, hypertension, diabetes, hyperlipidemia, and physical activity. Result The mean age of participants was 75.7 years, and 55% were female. Participants with handgrip strength asymmetry were mostly female, never smokers, and more likely to have lower handgrip strength. Handgrip strength asymmetry was associated with poor global cognition [ = ‐2.14, 95% confidence interval (CI): ‐3.60, ‐0.68] and digit span‐forward ( = ‐0.69, 95% CI: ‐1.25 to ‐0.14) over time in men. Low handgrip strength was associated with cognitive impairment (global cognition: = ‐1.13, 95% CI: ‐2.07 to ‐0.19; immediate free recall: = ‐0.48, 95%CI: ‐0.87 to ‐0.09; delayed free recall: = ‐0.45, 95% CI: ‐0.85 to ‐0.08); Trail Making Test‐ A: = ‐0.43, 95% CI: ‐0.75 to ‐0.12), and digit span‐forward ( = ‐0.67 to 95% CI: ‐1.02 to ‐0.31) over time in men. Concomitant weakness and handgrip strength asymmetry had greater impairment in cognitive function in men. Conclusion In this community‐dwelling older population, those with low handgrip strength and handgrip strength asymmetry had an increased risk of cognitive impairment. This relationship seems more prominent in men than women.