Hearing Loss Linked to Parkinson’s Disease: Insights from a Large-Scale Study

Recent research from electronic health records involving over 3 million US veterans found that hearing loss significantly increases the risk of developing Parkinson’s disease (PD). This correlation remains even when accounting for factors such as age, head trauma, frailty, and other related disorders. The study suggests that screening and treating hearing loss may help reduce the risk of synucleinopathy, a key feature of both PD and dementia.

Published in JAMA Neurology, the analysis evaluated data from the US Department of Veterans Affairs between January 1999 and December 2022. Of the veterans included, 20.8% had normal hearing. The study, led by Dr. Lee E. Neilson of the Portland VA Medical Center, monitored the cohort for an average of 7.6 years. During this period, the incidence of PD ranged from 3.69 to 11.6 cases per 10,000 person-years, while death rates ranged from 103 to 1140 per 10,000 person-years across different groups based on hearing ability. Veterans with mild hearing loss showed a higher cumulative incidence of PD over time compared to those with normal hearing.

Results indicated that any level of hearing loss was linked to a greater risk of PD after 10 years, with a hazard ratio of 1.26. The risk heightened with the severity of hearing loss and the length of time affected. When examining specific conditions, it was found that the combination of hearing loss and disorders related to early PD contributed to additional cases of PD beyond what was expected from each condition alone.

In an exploratory segment of the study, it was noted that using hearing aids within two years of an initial audiogram significantly reduced the incidence of PD. This effect appeared within just one year. About 462 veterans would need to be treated with hearing aids following an abnormal hearing test to prevent one individual from developing PD within a decade.

While the findings suggest a beneficial impact of hearing aids on PD risk, the study had limitations. The sample consisted predominantly of White male veterans, which may affect the applicability of the results to a broader population. Additional confounding factors, such as exposure to certain drugs, were not considered. Although this study points to a strong connection between hearing loss and PD, the exact cause and mechanisms remain uncertain.

Overall, the research emphasizes the importance of hearing health in potentially lowering the risk of developing Parkinson’s disease.

Reference:

Neilson LE, Reavis KM, Wiedrick J, et al. Hearing loss, incident Parkinson disease, and treatment with hearing aids. JAMA Neurol. Published online October 21, 2024. doi:10.1001/jamaneurol.2024.3568