Are shorter nights and midday naps linked to hearing loss?

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Hearing loss is an important concern for aging and health. Researchers investigated whether nighttime sleep and midday nap duration were associated with hearing loss in middle-aged and older adults.

The study included 9,573 adults from the China Health and Retirement Longitudinal Study who completed surveys about sleep characteristics and subjective functional hearing. Participants reported nighttime sleep in categories of less than 5, 5 to less than 6, 6 to less than 7, 7 to less than 9, or at least 9 hours per night, and midday naps of 5 minutes or less, 5 to 30 minutes, or more than 30 minutes. The researchers classified this information into sleep patterns. The primary outcome was self-reported hearing loss events.

Multivariate Cox regression models and restricted cubic splines were used to investigate longitudinal associations between sleep characteristics and hearing loss. Cox generalized additive models and bivariate exposure-response surface diagrams were used to visualize the effects of different sleep patterns on hearing loss.

During follow-up, 1,073 cases of hearing loss were identified; 55.1% were female. After adjustment for demographic characteristics, lifestyle factors and health condition, sleeping less than 5 hours a night was associated with hearing loss (hazard ratio [HR] 1.45, 95% confidence interval [CI] 1.20–1.75). People napping for 5 to 30 minutes had a 20% lower risk than those napping for 5 minutes or less (HR 0.80, 95% CI 0.63–1.00). Restricted cubic splines showed a reverse J-shaped association between nighttime sleep and hearing loss.

Sleeping less than 7 hours a night combined with napping for 5 minutes or less was associated with hearing loss (HR 1.27, 95% CI 1.06–1.52). The bivariate exposure-response surface diagrams also showed the highest risk with short sleep without napping. Compared with people who consistently slept 7–9 hours a night, those who consistently slept less than 7 hours, or shifted from less than 7 hours to moderate sleep or more than 9 hours, had higher risks of hearing loss.

The researchers concluded that inadequate nighttime sleep was associated with a higher risk of poor self-reported hearing in middle-aged and older adults, while moderate napping was associated with a lower risk of hearing loss. They suggested that keeping sleep stable within the recommended duration might help prevent poor hearing.