Cognitive function trajectories and influencing factors in Chinese older adults with self-reported hearing impairment: findings from CHARLS 2013-2020

Abstract

Objectives: Hearing impairment is linked to an increased risk of cognitive decline, yet the progression of cognitive function in affected individuals remains unclear. This study examined cognitive function trajectories in older adults with self-reported hearing impairment and identified key influencing factors.

Methods: Data from China Health and Retirement Longitudinal Study (CHARLS, 2013-2020) were analyzed. Sociodemographic and health-related factors, including age, education, sensory impairments, chronic conditions, hearing aid use, depression, vision, sleep patterns, social interactions, smoking, drinking, retirement status, and fuel use, were assessed. Cognitive function was evaluated using episodic memory, orientation, attention, and executive function. Group-Based Trajectory Modeling (GBTM) identified cognitive trajectories, while logistic regression examined influencing factors.

Results: Three cognitive trajectories were identified: low-functioning decline (L, 23.5%), middle-functioning decline (M, 38.5%), and high-functioning stabilization (H, 38.0%). The likelihood of M increased with younger age (60-69 years: OR = 8.56; 70-79 years: OR = 4.54), absence of physical (OR = 2.03) or visual impairment (OR = 1.65), and short naps (≤ 30 min, OR = 1.59). H was associated with younger age (60-69 years: OR = 60.36; 70-79 years: OR = 12.11), absence of physical (OR = 2.20) or visual disability (OR = 1.84), mild depression (OR = 3.91), and shorter naps (OR = 2.05). Poor hearing (OR = 0.46), illiteracy (OR = 0.03), and non-retirement (OR = 0.23) reduced the likelihood of being in the M or H groups (all p < 0.05).

Conclusions: Cognitive trajectories in hearing-impaired older Chinese adults fall into three categories: low-functioning decline, middle-functioning decline, and high-functioning stabilization. Age, education, sensory impairments, depression, nap duration, and retirement status influence these trajectories. Given the limited generalizability of these preliminary findings, further research is needed to clarify the potential confounding and mediating relationships among these factors before they can inform early intervention and policy initiatives.

Keywords: Cognitive trajectory; Group-based trajectory modeling; Hearing impairment; Influencing factor; Longitudinal analysis.