Serum per- and polyfluoroalkyl substances in relation to hearing loss

Abstract

Background: Studies have shown that per- and polyfluoroalkyl substances (PFAS) are potential ototoxicants. However, no epidemiologic study has been conducted. We conducted a cross-sectional study to examine the associations of PFAS with hearing impairment. Methods: This study included data from the National Health and Nutrition Examination Survey (NHANES) 1999-2000, 2003-06, and 2009-14 because only these year cycles contained all the information we needed. Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured in serum samples. Participants were divided into quartiles for each PFAS. Air conduction pure-tone audiometry was administered. Hearing impairment was defined as an average hearing threshold of more than 25dB at each hearing frequency. We assessed the relation of serum PFAS with hearing impairment by the generalized linear mixed model with a logit link and binary distribution. Tests for linear trend across quartiles of serum PFAS were conducted using the median serum PFAS in each quartile as a continuous variable. Results: A total of 2525 participants (women = 53.4%) aged 20 or above were included into the final analysis. After adjusted for age, sex, body mass index, education, ethnicity group, family income, and sampling weights, we found positive correlations between PFOA and hearing impairment at 2000 Hz (p-trend = 0.02) and 3000 Hz (p-trend = 0.01); between PFOS and hearing impairment at 2000 Hz (p-trend < 0.01) and 3000 Hz (p-trend = 0.01); between PFNA and hearing impairment at 3000 Hz (p-trend < 0.01), 4000 Hz (p-trend < 0.01), and 8000 Hz (p-trend = 0.03); between PFHxS and hearing impairment at 500 Hz (p-trend = 0.02), 1000 Hz (p-trend = 0.01), 2000 Hz (p-trend < 0.01), and 3000 Hz (p-trend = 0.03). Conclusion: Background serum PFASs are correlated with hearing impairment in the United States adult population.