Retinal Microvascular Abnormalities and Age-Related Hearing Loss: The Blue Mountains Hearing Study

Abstract

Microvascular disease may contribute to hearing loss. We tested this hypothesis by examining the relation of retinal microvascular abnormalities and hearing loss. This was a cross-sectional, population-based study. We performed retinal photography and pure-tone audiometry on 1511 older individuals (ages 54+ years) from the Blue Mountains Eye Study population. Examination of the retinal microvasculature provides a noninvasive means of assessing systemic microvascular changes associated with cardiovascular disease, especially since reliable methods of quantifying retinal microvascular abnormalities from retinal photographs have recently been developed. Trained graders masked to audiometry data assessed retinal photographs for signs of retinal microvascular damage, for example, focal arteriolar narrowing, arteriovenous nicking, and retinopathy (microaneurysms, retinal hemorrhages), and used a computer-assisted method to measure arteriolar and venular calibers. We defined moderate or profound hearing loss as pure-tone average air-conducted hearing thresholds in the better ear worse than 40 dB at 0.5, 1, 2, and 4 kHz. We used odds ratios (OR), 95% confidence intervals (CI), and probability values to present the associations between retinal microvascular abnormalities and hearing loss; an OR >1 indicates that persons with the microvascular abnormality are more likely to have hearing loss, a CI that includes 1.00 (e.g., 0.85 to 2.34) indicates no statistically significant association (i.e., the association may have occurred due to chance), whereas a value of p < 0.05 indicates that an association is unlikely to have occurred due to chance. The proportion of women and men with moderate or profound hearing loss was 10.4% (90/862) and 15.4% (100/649), respectively. After adjustment for age, sex, blood pressure, and other risk factors for hearing loss, retinopathy in women was associated with hearing loss (adjusted OR, 2.10; 95% CI, 1.09 to 4.06, p = 0.002) but not in men. Associations were stronger for moderate or worse low-frequency (0.25 to 1.0 kHz) hearing loss in women (adjusted OR, 3.00; 95% CI, 1.25 to 7.19, p = 0.0005) but were absent for high-frequency hearing loss. In men, no retinal microvascular abnormalities were associated with hearing loss at either low or high frequencies. Retinopathy, a sign of retinal microvascular damage, was associated with hearing loss in women but not in men. Our results provide modest support to the hypothesis that microvascular disease may play a role in age-related hearing loss in women, particularly low-frequency losses.