Smoking, central adiposity, and poor glycemic control increase risk of hearing impairment

To determine associations between smoking, adiposity, diabetes mellitus, and other risk factors for cardiovascular disease (CVD) and the 15-year incidence of hearing impairment (HI).

A longitudinal population-based cohort study (1993-95 to 2009-10), the Epidemiology of Hearing Loss Study (EHLS).

Beaver Dam, Wisconsin.

Participants in the Beaver Dam Eye Study (1988-90; residents of Beaver Dam, WI, aged 43-84 in 1987-88) were eligible for the EHLS. There were 1,925 participants with normal hearing at baseline.

Fifteen-year cumulative incidence of HI (pure-tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz greater than 25 decibels hearing level in either ear). Cigarette smoking, exercise, and other factors were ascertained according to questionnaire. Blood pressure, waist circumference, body mass index, and glycosylated hemoglobin were measured.

Follow-up examinations (≥1) were obtained from 87.2% (n=1,678; mean baseline age 61). The 15-year cumulative incidence of HI was 56.8%. Adjusting for age and sex, current smoking (hazard ratio (HR)=1.31, P=.048), education (<16 years; HR=1.35, P=.01), waist circumference (HR=1.08 per 10 cm, P=.02), and poorly controlled diabetes mellitus (HR=2.03, P=.048) were associated with greater risk of HI. Former smokers and people with better-controlled diabetes mellitus were not at greater risk.

Smoking, central adiposity, and poorly controlled diabetes mellitus predicted incident HI. These well-known risk factors for CVD suggest that vascular changes may contribute to HI in aging. Interventions targeting reductions in smoking and adiposity and better glycemic control in people with diabetes mellitus may help prevent or delay the onset of HI.