Cadmium, obesity, and education, and the 10-year incidence of hearing impairment: The beaver dam offspring study

Objectives/Hypothesis: To determine the 10-year incidence of hearing impairment (HI) and associated risk factors in the Beaver Dam Offspring Study (BOSS; 2004–present), a large middle-aged cohort followed for 10 years. Study Design: Prospective cohort study. Methods: Hearing thresholds were measured at baseline (2005–2008) and 5- (2010–2013) and 10-year (2015–2017) follow-up examinations. HI was defined as a pure-tone average >25 dB HL in either ear. BOSS participants free of HI at baseline with at least one follow-up examination (N = 2,065) were included. Potential risk factors evaluated included cardiovascular measures, health history, lifestyle factors, inflammatory markers, vitamins D and B12, lead, and cadmium. Results: Participants were 21 to 79 years (mean age = 47.9 years) at baseline. The 10-year cumulative HI incidence was 17.4% (95% confidence interval [CI]: 15.7–19.2) and was twice as likely in men (24.4%, 95% CI: 21.5–27.7) than in women (12.2%, 95% CI: 10.3–14.3). In a multivariable adjusted model, age (hazard ratio [HR] = 1.48, 95% CI: 1.38–1.59, per 5 years), male sex (HR = 2.47, 95% CI: 1.91–3.18), less than a college education (HR = 1.35, 95% CI: 1.02–1.79), body mass index (HR = 1.03, 95% CI: 1.01–1.05, per kg/m²), and higher cadmium levels (HR = 1.42, 95% CI: 1.05–1.92, quintile 5 vs. quintiles 1–4) were associated with the 10-year cumulative incidence of HI. There was no association between high lead levels, vitamins D or B12, and 10-year incidence of HI. Conclusions: In addition to age and sex, obesity, education, and blood cadmium levels were associated with increased incidence of HI. These prospective results add to evidence that age-related HI is a multifactorial preventable disorder. Level of Evidence: 2b Laryngoscope, 130:1396–1401, 2020.