Background
Hearing aid usage has been linked to improvements in cognition, communication, and socialization, but the extent to which it can affect the onset and progression of dementia is unknown. This study leveraged the National Alzheimer's Coordinating Center Uniform Data Set to longitudinally examine the association between the use of hearing aids and risk of progression from Mild Cognitive Impairment (MCI) to dementia as well as progression of dementia in hearing-impaired adults.
Methods
The sample included 977 participants aged >50 with MCI or all-cause dementia enrolled between 2005 and 2018. Participants were classified into four groups according to the definition of the duration of disease stage: Group 1, 450 participants with MCI at baseline that developed dementia during follow up; Group 2, 314 participants diagnosed with dementia at baseline and subsequently died during follow-up; Group 3, 126 healthy participants who were later diagnosed with MCI and then dementia at follow-up; Group 4, 87 participants with MCI at baseline who later converted to dementia and subsequently died during follow-up. Groups 3 and 4 were used to better capture the duration of MCI-to-dementia and dementia-to-death periods. Kaplan-Meier survival functions and survival analyses using Cox proportional hazards regression models were performed to assess the effect of hearing aid use on risk of MCI-to-dementia conversion and mortality risk in dementia participants. Sensitivity analyses were performed to control for confounding.
Results
Hearing aid users with MCI showed a reduced risk of developing dementia both in Group 1 (hazard ratio [HR] 0.56, 95%CI, 0.45-0.69; false discovery rate [FDR] p <.0001) and Group 3 (HR,0.42; 95%CI, 0.27-0.66; FDR p <.001). The mean progression rate in CDRSB was significantly higher for those who did not use hearing aids (p =.04). Hearing aid usage was also found to influence the progression of dementia. Hearing-aid users with dementia had a lower risk of death, both in Group 2 (HR,0.75; 95%CI, 0.60-0.95; FDR p =.038) and Group 4 (HR,0.53; 95%CI, 0.33-0.89; FDR p =.04). Our findings were robust subject to multiple sensitivity analyses.
Conclusions
Among hearing-impaired adults, hearing aid usage was significantly associated with reduced dementia risk and slower disease progression.