Age-related Hearing Loss, Vitamin B12, and Folate in the Elderly

Objective: Determine the correlation between the hearing threshold and the serum levels of vitamin B12 (cobalamin) and folic acid among elderly subjects (> 60 years) with age-related hearing loss (ARHL).

Study Design: Cross-sectional.

Setting: Community.

Subjects And Methods: Subjects included elderly who were found apparently healthy following repeated examination by physicians. The pure tone average (PTA) for the speech and high frequencies, and the serum folate and cobalamin were determined and the correlation found.

Results: The mean ± SD values of serum folate among the subjects with normal PTA in the speech frequencies (0-30 dB) was 412.3 nmol/L ± 17.6 nmol/L, while among those with hearing loss (HL), it was 279.1 nmol/L ± 17.2 nmol/L (P = 0.01). In the high frequencies, the mean ± SD values among the subjects with normal PTA was 426.3 nmol/L ± 17.6 nmol/L, while among those with HL, it was 279.14 nmol/L ± 171.2 nmol/L. The serum cobalamin among the subjects with normal PTA within the speech frequencies was 49.7 pmol/L ± 9.4 pmol/L, while among those with speech-frequency HL, it was 42.6 pmol/L ± 10.2 pmol/L. However, for high frequencies, the mean ± SD values among the subjects with normal PTA was 47.4 pmol/L ± 7.3 pmol/L, while among those with HL, it was 41.3 pmol/L ± 9.2 pmol/L. Spearman's correlation revealed that low folate (correlation coefficient = -0.27, P = 0.01) and cyanocobalamin (correlation coefficient = -0.35, P = 0.02) were significantly associated with increasing hearing threshold in the high frequencies. After adjusting for age, serum folate (correlation coefficient = -0.01, P = 0.01) was significant, while vitamin B12 (correlation coefficient = -0.01, P = 0.74) was not.

Conclusion: Serum folate was significantly lower among elderly with ARHL. Trials on nutritional supplementation may substantiate the role of serum folate in ARHL.