Association of baseline cognitive function and hearing loss with cognitive trajectory group membership among Chinese...

Cognitive aging is heterogeneous, but the role of hearing loss in distinct cognitive trajectories remains unclear. We examined associations of hearing loss with cognitive trajectory membership and its modification of the association between baseline cognition and subsequent cognitive change among Chinese older adults.

Data were from the Chinese Longitudinal Healthy Longevity Survey. We included 6650 adults aged 65-99 years with at least two valid Mini-Mental State Examination (MMSE) assessments between 2008 and 2018. Growth mixture modelling identified cognitive trajectories, and multinomial logistic regression examined associations of baseline hearing loss and MMSE score with trajectory group membership and tested their interaction.

Three trajectories were identified: high-stable (83.3%), moderate decline (11.2%), and rapid decline (5.5%). Higher baseline MMSE scores were associated with lower relative likelihoods of moderate decline (RRR 0.875, 95% CI 0.859-0.892) and rapid decline (RRR 0.920, 95% CI 0.898-0.942). Hearing loss was associated with higher relative likelihoods of moderate decline (RRR 1.262, 95% CI 1.018-1.565) and rapid decline (RRR 1.551, 95% CI 1.188-2.025). The MMSE-by-hearing interaction was significant for moderate decline (RRR 1.252, 95% CI 1.079-1.453), indicating a weaker inverse association between baseline MMSE and moderate-decline membership among participants with hearing loss.

Hearing loss was associated with adverse cognitive trajectory membership and modified the association between baseline cognitive function and moderate decline. The association with rapid decline was particularly consistent across sensitivity analyses. These findings support considering hearing status when assessing cognitive aging risk, while further studies should determine whether hearing interventions alter cognitive trajectories.