Risk factors for hearing loss in US adults: data from the National Health and Nutrition Examination Survey, 1999 to 2002.

To evaluate and compare the effects of cardiovascular risk factors (hypertension, smoking, diabetes) and noise exposure (occupational, recreational, firearm) on frequency-specific audiometric thresholds among US adults while assessing synergistic interactions between these exposures. National cross-sectional survey. United States adults aged 20 to 69 years who participated in the 1999 to 2002 National Health and Nutrition Examination Survey (N = 3,527). Air-conduction thresholds at 0.5 to 8 kHz (dB) in the poorer-hearing ear. Multivariate models adjusted for age, sex, race/ethnicity, and educational level. : Exposure to firearm noise was significantly associated with high-frequency (4-8 kHz) hearing loss (HL), whereas smoking and diabetes were associated with significantly increased hearing thresholds across the frequency range (0.5-8 kHz). A significant interaction was observed between exposure to firearm noise and heavy smoking such that firearm noise was associated with a mean 8-dB hearing loss in heavy smokers compared with a mean 2-dB hearing loss in nonsmokers at 8 kHz. We also observed significant interactions between firearm noise exposure and diabetes. Noise exposure was associated with high-frequency HL, whereas cardiovascular risk generated by smoking and diabetes was associated with both high- and low-frequency HL. The frequency-specific effects of these exposures may offer insight into mechanisms of cochlear damage. We demonstrated an interaction between cardiovascular risk and noise exposures, possibly as a result of cochlear vulnerability due to microvascular insufficiency. Such significant interactions provide proof of principle that certain preexisting medical conditions can potentiate the effect of noise exposure on hearing. Data-based stratification of risk should guide our counseling of patients regarding HL.