Estimating the impact of different types hearing loss on cognitive decline and the joint effect of hearing loss and depression on cognitive decline among older adults in China

Abstract

Background: Current research lacks examination of the relationship between different subtypes of hearing loss (HL) and cognitive decline (CD). Additionally, the co-effects of HL and depression on CD remain unexplored. This study aims to investigate the relationship between HL, various types of HL, and CD, as well as the combined impact of HL and depression on CD.

Methods: Data from a total of 5218 older adults who participated in the most recent three waves of Chinese Longitudinal Healthy Longevity Survey (CLHLS) (2011-2012, 2014, and 2018) were included. HL was assessed through self-report and objective measures. CD was defined as a decrease in MMSE score of≥3 between any two survey periods for older adults. Cox proportional hazards model was applied to analyzed.

Results: Among Chinese older adults, bilateral HL (HR = 1.202, 95%CI = 1.093-1.322, P < 0.001), onset of HL after the age of 40 (HR = 1.155, 95%CI = 1.056-1.264, P = 0.002), and chronic HL (HR = 1.143, 95%CI = 1.040-1.255, P = 0.005) posed a greater risk. HL (HR = 1.146, 95%CI = 1.048-1.254, P = 0.003) and depression (HR = 1.162, 95%CI = 1.038-1.301, P = 0.009) were independently or jointly associated with CD. Participants who were simultaneously exposed to both HL and depression experienced the highest risk of CD (HR = 1.314, 95%CI = 1.117-1.545, P = 0.001).

Limitations: Given the observational design, unidentified confounding variables may still be present, such as whether to wear a hearing aid.

Conclusion: This study emphasizes the high risk of specific types of HL for CD and the importance of implementing health interventions that address both physiological and psychological aspects to enhance cognitive function and prevent CD in older adults.

Keywords: Cognitive decline; Cox proportional hazards model; Depression; Hearing loss; Older Chinese adults.