Background: Hearing impairment is 1 of the 4 most prevalent chronic conditions in the elderly. However, the biological basis of age-related hearing loss is unknown. Objective: The objective was to test the hypothesis that agerelated hearing loss may be associated with poor vitamin B-12 and folate status. Design: A thorough audiometric assessment was conducted in 55 healthy women aged 60-71 y. Hearing function was determined by the average of pure-tone air conduction thresholds at 0.5, 1, 2, and 4 kHz and was categorized into 2 groups for logistic regression analyses: normal hearing (< 20 dB hearing level; n = 44) and impaired hearing (≥ 20 dB hearing level; n = 11). Results: Mean age was the same (65 y) for the normal hearing and impaired hearing groups. Pure-tone averages were inversely correlated with serum vitamin B-12 (r = Ϫ0.58, P = 0.0001) and red cell folate (r = Ϫ0.37, P = 0.01). Women with impaired hearing had 38% lower serum vitamin B-12 (236 compared with 380 pmol/L, respectively, P = 0.008) and 31% lower red cell folate (425 compared with 619 nmol/L, respectively, P = 0.02) than women with normal hearing. Among participants who did not take supplements containing vitamin B-12 or folate, women with impaired hearing had 48% lower serum vitamin B-12 (156 compared with 302 pmol/L, respectively, P = 0.0007) and 43% lower red cell folate (288 compared with 502 nmol/L, respectively, P = 0.001) than women with normal hearing. Conclusion: Poor vitamin B-12 and folate status may be associated with age-related auditory dysfunction.Am J Clin Nutr 1999;69:564-71.

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