Association between Hearing Difficulty, Masticatory Difficulty, and Risk of Cognitive Impairment: Analysis of the Korean Longitudinal Study of Aging Data (2006-2020)

Purpose: This study aimed to identify the association between hearing difficulty, masticatory difficulty, and cognitive impairment using data from the Korean Longitudinal Study of Aging. Methods: This secondary data analysis included 6939 Korean adults aged 45 or older with no cognitive impairment at baseline. Self-reported questionnaires measured hearing and masticatory difficulty, and cognitive impairment were assessed using the Korea Mini-Mental State Examination (K-MMSE). Cox models were used to estimate the risk of cognitive impairment associated with the coexistence of hearing and masticatory difficulty.Results: People who coexisted with hearing and masticatory difficulty were 2.4%. The incidence rate of cognitive impairment was 37.7% for the study sample and higher in females than males. Compared to people without hearing and masticatory difficulty, the total study sample with the coexistence of hearing and masticatory difficulty had a higher risk of cognitive impairment (HR: 1.26, 95% CI: 1.03–1.56), females with the coexistence of hearing and masticatory difficulty had a greater risk of cognitive impairment (HR :1.52 95% CI: 1.11–2.09). Conclusion: Coexistence of hearing and masticatory difficulty increased females' cognitive impairment risk. It is recommended to check hearing and masticatory function in a timely, which may be effective in detecting individuals at high risk of cognitive impairment.