ELSA-Brasil: a 4-year incidence of hearing loss in adults with and without hypertension

Abstract

OBJECTIVE: To compare the incidence of hearing loss among adults stratified by the occurrence of hypertension, and to investigate the association between hypertension and hearing loss. METHODS: Longitudinal observational study, part of the Estudo Longitudinal da Saude do Adulto (ELSA-Brasil, Longitudinal Study on Adult's Health). Data from the first and second waves were analyzed, including information from audiological assessment and general health of the subjects. As outcome, we considered the presence of hearing loss (hearing thresholds above 25 dBHL at frequencies from 500 Hz to 8 kHz) and, as exposure variable, hypertension (report of medical diagnosis of hypertension; and/or use of drugs to treat hypertension; and/or pressure systolic blood pressure >= 140 mmHg; or diastolic blood pressure >= 90 mmHg). As covariables for adjustment were considered: sex, age, education, race / ethnicity, income, smoking, diabetes, and occupational exposure to noise. Poisson regression analysis was conducted, estimating the crude and adjusted relative risks, with 95% confidence intervals, in order to assess the factors associated with hearing loss. RESULTS: In crude analyses, the incidence of hearing loss was higher for subjects with hypertension (9.7% versus 5.4%). The crude relative risks for hearing loss was almost double (1.93; 95%CI: 1.10-3.39) for subjects with hypertension in the right ear. In the adjusted analyses, the relative risks was not significant for the hypertension variable (1.42; 95%CI: 0.75-2.67). Being 60 years or older (RR: 5.41; 95%CI: 2.79-10.50) showed a statistically significant association with hearing loss, indicating that older adults have higher relative risks for hearing loss. CONCLUSION: In the adjusted analyses controlled for multiple risk factors there was no association between hypertension and hearing loss. The dichotomous variable age (being 60 years or older), on the other hand, has shown a significant association with hearing loss.