Healthful Diets and Risk of Hearing Loss

The primary outcome, self-reported hearing loss that was moderate or worse in severity, was determined based on responses to the 2009 and 2013 questionnaires on which participants were asked about their hearing. On the 2009 main questionnaire, participants were asked, "Do you have a hearing problem?" (no, mild, moderate, severe), and "At what age did you first notice a change in your hearing?" On the 2013 main questionnaire, participants were asked, "Which best describes your hearing?" (excellent, good, a little hearing trouble, moderate hearing trouble, deaf), and "Have you noticed a change in your hearing?" and, if the response was "Yes," "At what age did you first notice a change in your hearing?"

Detailed hearing-related information was collected electronically in 2012 supplemental questionnaire from a representative subcohort of NHS II participants (n= 33,102) with and without reported hearing problems, including information on previous evaluation for hearing loss, laterality (unilateral or bilateral), and identified causes of hearing loss (e.g. ototoxic medications, ear trauma, otosclerosis, cholesteatoma, Meniere's disease, chronic ear infection). Data from the HSSQ were used to conduct sensitivity analyses using more refined case definitions (e.g. excluding known etiologies and unilateral hearing loss).