Association of leukocyte telomere length and the risk of age-related hearing impairment in Chinese Hans.

Age-related hearing loss (ARHI) is the most common sensory disorder in the elderly. Although telomere attrition has been shown as a determinant in the pathobiology of various age-related diseases, it remains unknown whether telomere length is associated with ARHI. We hypothesized that decreased leukocyte telomere length (LTL) increased the risk of ARHI. Thus, we measured LTL of 666 ARHI and 43 controls by an established quantitative PCR technique. Four audiogram shape subtypes of ARHI, including "flat shape (FL)", "2-4 kHz abrupt loss (AL) shape", "8 kHz dip (8D) shape" and "sloping shape (SL)" could be identified among the cases using K-means cluster analysis. Longer LTL was associated with the reduced incidence of ARHI (adjusted OR = 0.550, 95% CI: 0.420-0.721, P < 0.0001 for all the ARHI; 0.498, 0.318-0.780, P = 0.0023 for FL subgroup; 0.428, 0.292-0.628, P < 0.0001 for AL subgroup; 0.552, 0.399-0.764, P = 0.0003 for mSL subgroup). Subjects in the highest tertile of LTL were at less risk for ARHI than those in the lowest and middle tertiles (OR for ARHI: 0.327, 95% CI 0.170-0.629, P = 0.0008). There was a descending trend of LTL as the degree of pure tone threshold average (PTA) aggravated. These results suggest that telomere attrition may be involved in the progression of ARHI.