Hearing loss and cognitive decline in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) during eight years of follow-up.

BackgroundHearing loss (HL) of moderate or higher grades is common in older adults with increasing prevalence as people age, rising from 12% at the age of 60 years to over 58% at 90 years. HL in midlife is one of the main potentially modifiable risk factors for dementia. It is estimated that 7% of dementia cases globally could be avoided if this risk factor was eliminated. However, much of the research conducted has been in high-income countries even though low- and middle-income countries have the highest prevalence of dementia.ObjectiveTo study the association between HL and cognitive decline during eight years of follow-up in a Brazilian sample.MethodsParticipants from the São Paulo center of the Brazilian Longitudinal Study of Adult Health were evaluated in three study waves (2008-10, 2012-14, and 2017-19). HL was defined as pure-tone audiometry above 25 dB in the better ear. Cognitive performance was evaluated with six tests related to memory, verbal fluency, and trail-making tests. A global cognitive z-score was derived from these tests. The association between HL and cognitive decline was evaluated with linear mixed-effects models adjusted for sociodemographic, lifestyle, and clinical factors.ResultsOf 805 participants (mean age 51 ± 9 years, 52% women, 60% White), 62 had HL. During follow-up, HL was associated with faster global cognitive decline (β = -0.012, 95% CI = -0.023; 0.000,  = 0.039).ConclusionsHL was significantly associated with a faster rate of global cognitive decline after a median follow-up of eight years in a sample of middle-income country.