A new study of almost 14,000 people found high and low frequency hearing impairment to be associated with sleep apnea.
“In our population-based study of 13,967 subjects from the Hispanic Community Health Study/Study of Latinos, we found that sleep apnea was independently associated with hearing impairment at both high and low frequencies after adjustment for other possible causes of hearing loss,” said lead author Amit Chopra, MD.
The participants all underwent in-home sleep apnea studies as well as on-site audiometric testing at their baseline. Assessment of sleep apnea was done with the apnea-hypopnea index (AHI). The AHI measures sleep apnea intensity based on the number of apnea, or complete cessation of airflow, and hypopneas, the partial cessation of airflow, per hour of sleep.
Hearing Impairment and Sleep Apnea
An AHI equal to or more than 15 events/hour was defined as sleep apnea. High frequency hearing impairment was defined as having a mean hearing threshold of greater than 25 decibels in either ear at 2000, 3000, 4000, 6000 and 8000 Hz, and low frequency hearing impairment was defined as having a mean hearing threshold of greater than 25 decibels in either ear at 500 Hz and 1000 Hz.
Out of 13,967 study subjects, 9.9% had at least moderate sleep apnea. 19.0% of participants had high frequency hearing loss, 1.5% had low frequency hearing impairment, and 8.4% had both high and low frequency hearing impairment.
Hearing impairment was found to be more common in those of Cuban and Puerto Rican descent. It was also seen more among those with a higher body mass index, self-reported snoring and/or sleep apnea.
Sleep Apnea was associated independently with:
– 31% increase in high frequency hearing impairment – 90% increase in low frequency hearing impairment – 38% increase in combined high and low frequency hearing impairment
This analyses was adjusted for factors including history of hearing impairment, age, sex, background, external noise exposure, and conductive hearing loss. Increasing AHI was associated with a higher prevalence of high frequency, but not low frequency hearing impairment.
“Patients with sleep apnea are at increased risk for a number of comorbidities, including heart disease and diabetes, and our findings indicate that sleep apnea is also associated with an increased risk of hearing impairment” said Dr. Chopra. “The mechanisms underlying this relationship merit further exploration. Potential pathways linking sleep apnea and hearing impairment may include adverse effects of sleep apnea on vascular supply to the cochlea via inflammation and vascular remodeling or noise trauma from snoring .”
One flaw of this study was that the authors could not factor the impact of treatment of sleep apnea on their findings. It was rare, however, for the participants in this group to be on sleep apnea treatment.