The interrelationships of hearing function, allostatic load, and cognitive function: Evidence among middle-aged and older Chinese adults

We aim to examine the interrelationships of self-reported hearing function, allostatic load (AL), and cognitive function among middle aged and older adults. Our data were collected from two waves of the China Health and Retirement Longitudinal Study (CHARLS) conducted in 2011 and 2015. The participants' hearing function was measured using self-rated subjective hearing function. Allostatic load (AL) was evaluated by measuring 14 biomarkers associated with physiological health, which were derived from blood samples. Cognitive function was assessed using three domains: episodic memory, mental intactness, and global cognition. To examine the relationships between hearing function, AL, and cognitive function, path analysis with structural equation modeling (SEM) methodology was employed. Among individuals aged 60 and above non-hearing aids users, the hearing function at Time 1 (T1) in 2011 has a significant association with the level of AL at T1 (β = 0.02, p < 0.001), as well as on cognitive function at Time 2 (T2) in 2015 (β = −0.1, p < 0.001). Additionally, the AL related to the hearing function at T1 associates an increased risk of AL at T2 (β = 0.5, p < 0.001), and is significantly associated with a decrease of cognitive function scores at T2 (β = −0.4, p < 0.001). However, no significant relationship was found among individuals aged 45 – 59 with non-hearing aids utilizers. Similar findings were in the domains of epidemic memory and mental intactness for cognitive function. There were interrelationships of subjective hearing function, AL, and cognitive function among aged 60 years and above, but not among those aged 45–59 years old. It may provide valuable insights for identifying subclinical thresholds in the physiological systems of individuals at risk of pathology in cognitive function.