LAUSR

Objectives Chronic otitis media (COM) is caused by an infection of the middle ear, although it may also be associated with environmental pollutants. Recent reports found that cadmium exposure could be toxic to middle ear cell lines, but the role of cadmium in the development of COM in humans has not been examined to date. We hypothesised that environmental cadmium exposure was associated with an increased risk of COM in the general population. Methods We analysed cross-sectional data for 5331 adults of 20 years of age or above, obtained from the Korea National Health and Nutrition Examination Survey 2010–2012. We examined the association between blood cadmium levels and COM diagnosed by an otolaryngologist. Results The highest quartile group of cadmium blood concentration was associated with an OR of 3.33 (95% CI 1.78 to 7.53) for COM, after adjusting for potential confounding factors. Doubling blood cadmium concentration resulted in an OR of 1.58 (95% CI 1.19 to 2.08) for COM. These associations were robust on sensitivity analyses after excluding current smokers and former smokers and after excluding subjects with a potential history of occupational exposure to cadmium. Conclusions The results of our study suggest that environmental cadmium exposure is associated with increased risk of COM, and further studies are warranted to understand the pathogenetic mechanism by which COM is caused by cadmium exposure.