PLoS ONE (Jan 2018)

Arsenic level in toenails is associated with hearing loss in humans.

  • Xiang Li,
  • Nobutaka Ohgami,
  • Ichiro Yajima,
  • Huadong Xu,
  • Machiko Iida,
  • Reina Oshino,
  • Hiromasa Ninomiya,
  • Dandan Shen,
  • Nazmul Ahsan,
  • Anwarul Azim Akhand,
  • Masashi Kato

DOI
https://doi.org/10.1371/journal.pone.0198743
Journal volume & issue
Vol. 13, no. 7
p. e0198743

Abstract

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Arsenic (As) pollution in drinking water is a worldwide health risk for humans. We previously showed hearing loss in young people who live in areas of As-polluted drinking water and in young mice orally treated with As. In this study, we epidemiologically examined associations between As levels in toenails and hearing in 145 Bangladeshi aged 12-55 years in 2014. Levels of As in toenails, but not those in urine, were shown to be significantly correlated with hearing loss at 4 kHz [odds ratio (OR) = 4.27; 95% confidence interval (CI): 1.51, 12.05], 8 kHz (OR = 3.91; 95% CI: 1.47, 10.38) and 12 kHz (OR = 4.15; 95% CI: 1.55, 11.09) by multivariate analysis with adjustments for age, sex, smoking and BMI. Our experimental study further showed a significant association between As levels in inner ears and nails (r = 0.8113, p = 0.0014) in mice orally exposed to As, suggesting that As level in nails is a suitable index to assess As level in inner ears. Taken together, the results of our study suggest that As level in nails could be a convenient and non-invasive biomarker for As-mediated hearing loss in humans.