Differences in the distribution of sociodemographic characteristics, military history, noise exposure (leisure time and occupational), ototoxic medication use, smoking, and diagnosed diabetes were tested by using the t test (for continuous characteristics) or chi-square test (for categorical characteristics). Unadjusted prevalence estimates and 95% CIs for the hearing impairment outcomes were assessed by diagnosed diabetes status. Prevalence estimates were additionally stratified by sociodemographic characteristics, military history, leisure-time noise exposure, occupational noise exposure, ototoxic medication use, and smoking to identify population subgroups that may be particularly vulnerable to diabetes-related hearing impairment. Age-adjusted prevalence estimates were computed by direct standardization to the 2000 U.S. Census population by using age categories of 20 to 49 years, 50 to 59 years, and 60 to 69 years. Statistical significance of the difference between unadjusted estimates was determined from chi-square test statistics for a general association, and the Cochran–Mantel–Haenszel chi-square test was used to determine the statistical significance of the difference between age-adjusted estimates. For the 2259 participants who had been randomly assigned to the fasting protocol, age-adjusted prevalence estimates of high-frequency hearing impairment were generated by glycemic status (diagnosed diabetes, undiagnosed diabetes, impaired fasting glucose, or normal). Odds ratios (with 95% CIs) for the independent association of diabetes with hearing impairment were estimated by using multiple logistic regression models, adjusting for age, sex, race or ethnicity, education, income– poverty ratio, leisure-time noise exposure, occupational noise exposure, history of military service, use of ototoxic medications, and smoking. Age was treated as a continuous variable in all regression models. Nonlinear effects of age on the logit of each outcome were examined by testing the addition of an age squared term to each model but were not statistically significant. By using the concordance index, we assessed predictive accuracy, which ranged from 80% to 90% for each of the 8 audiometrically assessed outcomes and was 72% for self-reported hearing impairment. Six of the 9 models passed the Hosmer–Lemeshow goodness-of-fit tests. Finally, the frequency-specific pure tone thresholds were examined graphically by averaging within-person thresholds over both ears and plotting the age-adjusted and age-specific mean thresholds stratified by diagnosed diabetes status.