In a study on the association between chronic obstructive pulmonary disease (COPD) and long-term hearing loss, researchers found that people with COPD had higher incidences of hearing decline at low and mid frequencies over 20 years. “Our large cohort study showed an association between COPD and increased long-term hearing decline,” wrote the researchers of this study. “Our study also suggests that women may be more vulnerable to COPD-related high frequency hearing loss.” The results of this cohort study were published in Respiratory Medicine.

COPD and hearing loss are conditions associated with reduced oxygen, with previous studies showing an association between COPD and poorer pure tone hearing threshold, suggesting that COPD may affect hearing function. Furthermore, the researchers wanted to examine if gender presents different disease risk between men and women for both COPD and hearing loss.

This study is a subanalaysis of data from The Trøndelag Health Study (HUNT), a population cohort study in Norway and one of the world’s largest population-based health studies, which included baseline patient characteristics from 1996 to 1998 and a follow-up from 2017 to 2019.

A total of 12,082 patients were included in the sample population, and they all had with a minimum of 1 registered International Classification of Diseases, 10th Revision (ICD-10) for emphysema or other COPDs during follow-up, and 20-year hearing decline at mid, low, and high frequency levels (0.25-0.5/1-2/3-8 kHz). The researchers adjusted for age, sex, education, smoking status, noise exposure, ear infections, hypertension, and diabetes.

The researchers identified 403 patients with COPD who had a larger 20-year hearing decline at low frequency decibels (dB, 1.5; 95% CI, 0.6-2.3) and mid frequencies (dB, 1.2; 95% CI, 0.4-2.1), but not at high frequencies. At high frequencies, the association was stronger among women (dB, 1.9; 95% CI, 0.6-3.2) compared with men.

Lastly, 19 patients with COPD and respiratory failure had a larger 20-year hearing decline at low (dB, 7.4; 95% CI, 3.6-11.2) and mid frequencies (dB, 4.5; 95% CI, 0.7-8.4). A limitation that the researchers acknowledge was the lack of spirometry and data available on the duration that a patient had COPD, as well as data on the time to COPD onset. Furthermore, the researchers believed that younger patients probably had shorter durations of COPD as well as more mild exacerbations compared with older patients, which may have explained a stronger association with hearing loss in older patients vs younger patients.

Despite these limitations, the results of this study suggest an association between COPD and long-term hearing decline, of which women may be more vulnerable to than men. “The effect sizes were small, and we believe the clinical implications with respect to persons with COPD are limited,” concluded the researchers. “Our study adds strengths to prior findings and contributes towards better understanding of the pathophysiology of hearing loss.