Associations between dietary indices and hearing status among middle-older aged adults- Results from the Baltimore Longitudinal Study of Aging.

BACKGROUND: Hearing loss, a public health issue in older populations, is closely related to functional decline.

OBJECTIVE: Investigate the longitudinal associations between four dietary indices and hearing status.

METHODS: Data from the Baltimore Longitudinal Study of Aging were used and included 882 participants ≥ 45 years of age. Dietary intake was assessed by a validated food frequency questionnaire and four diet scores (Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay diet [MIND], Mediterranean style diet [MDS], Alternative Healthy Eating Index [AHEI], and Healthy Eating Index [HEI]) were calculated as averages over time. Hearing status was examined using pure-tone audiometry, and pure-tone average (PTA) of hearing thresholds were calculated at speech level (PTA(500, 1000, 2000, 4000 Hz) ), low (PTA(500, 1000 Hz) ) and high (PTA(4000, 8000 Hz) ) frequencies, with lower thresholds indicating better hearing. Multivariable linear mixed effect models were used to examine associations between dietary indices and hearing thresholds change over time adjusted for confounders.

RESULTS: At baseline, the mean age of participants was 67 years, with 55% female. Over a median of 8 years of follow-up, MDS≥7 was associated with 3.5 (95% CI: -6.5, -0.4) and 5.0 (95% CI: -9.1, -1.0) dB lower PTA(500, 1000, 2000, 4000 Hz) and PTA(4000, 8000 Hz) as compared to MDS≤3; the highest tertile of the AHEI was associated with 2.3 (95% CI: -4.6, -0.1) and 5.0 (95% CI: -8.0, -2.0) dB lower PTA(500, 1000, 2000, 4000 Hz) and PTA(4000, 8000 Hz) ; and each standard deviation increment in the HEI was associated with 1.6 dB (95% CI: -2.7, -0.6), 1.1 dB (95% CI: -2.1, -0.1), and 2.1 dB (95% CI: -3.5, -0.6) lower PTA(500, 1000, 2000, 4000 Hz) , PTA(500, 1000 Hz) , and PTA(4000, 8000 Hz) , respectively.

CONCLUSIONS: Adherence to healthy dietary patterns was associated with better hearing status, with stronger associations at high frequencies.