Manganese in toenails is associated with hearing loss at high frequencies in humans |
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| Authors: | Nobutaka Ohgami Xiang Li Ichiro Yajima Reina Oshino Kyoko Ohgami Yoko Kato |
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| Institution: | 1. Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya, Japan;2. Voluntary Body for International Health Care in Universities, Nagoya, Japan |
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| Abstract: | Purpose: Elevated hearing thresholds from high frequencies are known to be one of the hallmarks of age-related hearing loss. Our recent study showed accumulation of manganese (Mn) in inner ears resulting in acceleration of age-related hearing loss in mice orally exposed to Mn. However, there is no evidence showing an association between Mn in non-invasive biological samples and hearing loss in humans evaluated by pure tone audiometry (PTA). In this study, we evaluated Mn in non-invasive biological samples as a possible biomarker for hearing loss in humans.Materials and methods: We determined hearing levels by PTA and Mn levels in toenails, hair and urine with an inductively coupled plasma mass spectrometer (ICP-MS) in 145 healthy subjects in Bangladesh.Results: Multivariable analyses showed that Mn levels in toenails, but not in hair and urine samples, were significantly associated with hearing loss at 8?kHz and 12?kHz. Moreover, our experimental study showed a significant correlation between Mn levels in inner ears and nails, but not hair, in mice orally exposed to Mn.Conclusions: The results provide novel evidence that Mn in toenails is a possible biomarker for hearing loss at high frequencies in humans. |
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| Keywords: | Manganese hearing loss toenails inner ears ICP-MS |
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