Association of midlife hearing impairment and hearing aid use with incident dementia: analysis of two UK-based longitudinal cohort studies.

The prevalence of hearing impairment and dementia increases with age but the nature of their association remains unclear. Using data from two large UK-based cohort studies, we examined the longitudinal association of 'midlife' hearing impairment and hearing aid use with incident dementia. We found modest associations and population attributable fractions for reported and measured 'midlife' hearing impairment, highlighting the need to consider age at measurement of risk factors in studies that target dementia prevention.