Correlation between Serum Immunoglobulin G and Hearing Threshold among Elderly Subjects with Age-Related Hearing Loss

Background and Purpose: This study was based on the hypothesis that suboptimal immune response and low serum immunoglobulin G (IgG) may predispose to age-related hearing loss (ARHL), and the objective was to determine the serum levels of IgG and hearing thresholds of apparently healthy elderly subjects and assess their correlation. Method: This prospective study involved 126 participants ≧60 years old who were found to be free of any medical conditions. Pure-tone averages for both the speech (500–2,000 Hz) and high frequencies (3,000–8,000 Hz) and serum IgG levels were determined. Using 30 dB as cut-off for hearing loss, the correlation with serum IgG was assessed. Results: There were 59 males and 67 females with a mean age ± SD of 67.0 ± 2.7 years. Speech frequency hearing loss was seen in 30.2%, while high-frequency hearing loss accounted for 74.6%. In the speech frequencies, the mean ± SD of serum IgG among subjects with normal hearing was 11.3 ± 3.9 g/l, while among those with hearing loss it was 8.3 ± 3.3 g/l (p = 0.01). In the high frequencies, the mean ± SD values of serum IgG among the subjects with normal hearing was 11.1 ± 2.3 g/l, while among those with hearing loss it was 8.7 ± 1.9 g/l (p = 0.01). Conclusion: Low serum IgG may be a contributory factor to the development of ARHL among the elderly. However, a longitudinal study involving intervention with immunoglobulin supplementation may further confirm this role.