Synergistic associations of visual and self-reported hearing acuity with low handgrip strength in older adults: a population-based cross-sectional study.

BACKGROUND It is unclear whether visual and hearing acuity are independently or synergistically associated with muscle strength. We aimed to examine the associations of visual and self-reported hearing acuity with low handgrip strength and the additive interaction between visual and hearing acuity on low handgrip strength in people over 60 years. METHOD Data of 3,075 individuals aged over 60 years from the 2017 and 2018 Korea National Health and Nutrition Examination Survey were used for this cross-sectional study. Low handgrip strength was defined based on the 20th percentile of the study population (< 30.4 kg for male and < 17.7 kg for female). Visual and self-reported hearing acuity were each divided into three categories: good, moderate, and impaired. Multiple logistic regression and relative excess risk due to interaction (RERI) were performed. RESULTS Of the 3,075 participants, 993 (32.3 %) demonstrated low handgrip strength. Low handgrip strength was more prevalent in participants with moderate (adjusted odds ratio [AOR] = 1.54, 95 % confidence interval [CI] = 1.12-2.12) and impaired visual acuity (AOR = 2.00, 95 % CI = 1.34-2.96). Both moderate and impaired self-reported hearing acuity were significantly associated with low handgrip strength (moderate: AOR = 1.25, 95 % CI = 1.01-1.55; impaired: AOR = 1.66, 95 % CI = 1.15-2.38). The more severe the sensory function decline, the higher the association with muscle weakness. Moreover, combined sensory impairments were associated with deteriorating low handgrip strength (AOR = 8.38), with significantly strong additive interactions (RERI = 2.61, 95 % CI = 2.52-2.70). CONCLUSIONS Awareness is needed regarding the risk of reduced muscle strength in individuals with moderate and impaired sensory function. Older people with sensory function decline in clinical settings may benefit from programs such as exercise prescription to prevent muscle weakness.