The effect of association between inefficient arsenic methylation capacity and demographic characteristics on the risk of skin lesions

Hifza Rasheed; Paul Kay; Rebecca Slack; Yun Yun Gong

doi:10.1016/j.taap.2017.11.026

The effect of association between inefficient arsenic methylation capacity and demographic characteristics on the risk of skin lesions

Toxicol Appl Pharmacol. 2018 Jan 15:339:42-51. doi: 10.1016/j.taap.2017.11.026. Epub 2017 Nov 29.

Authors

Hifza Rasheed¹, Paul Kay², Rebecca Slack², Yun Yun Gong³

Affiliations

¹ water@leeds, School of Geography, University of Leeds, Leeds LS2 s9JT, United Kingdom. Electronic address: gyhj@leeds.ac.uk.
² water@leeds, School of Geography, University of Leeds, Leeds LS2 s9JT, United Kingdom.
³ School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, United Kingdom.

PMID: 29197518
DOI: 10.1016/j.taap.2017.11.026

Abstract

This study was conducted in rural Pakistan to assess the dose-response relationship between skin lesions and arsenic exposure and their variation by demographic characteristics. The study included 398 participants (66 participants with skin lesions and 332 without) residing in six previously unstudied villages exposed to ground water arsenic in the range of <1 to 3090μgL^-1. The skin lesions identification process involved interview and physical examinations of participants followed by confirmation by a physician according to UNICEF criteria. Urinary inorganic arsenic (iAs), total arsenic (tAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were analysed to determine methylation capacity, methylation efficiency and the dose-response relationship with skin lesions. Study participants with skin lesions were found to be exposed to arsenic >10μgL^-1 with a daily arsenic intake of 3.23±3.75mgday^-1 from household ground water sources for an exposure duration of 10-20years. The participants with skin lesions compared to those without skin lesions showed higher levels of urinary iAs (133.40±242.48 vs. 44.24±86.48μgg^-1Cr), MMA (106.38±135.04 vs. 35.43±39.97μgg^-1Cr), MMA% (15.26±6.31 vs.12.11±4.68) and lower levels of DMA% (66.99±13.59 vs. 73.39±10.44) and secondary methylation index (SMI) (0.81±0.11 vs. 0.86±0.07). Study participants carrying a lower methylation capacity characterized by higher MMA% (OR 5.06, 95% CI: 2.09-12.27), lower DMA% (OR 0.64, 95% CI: 0.33-1.26), primary methylation index (PMI) (OR 0.56, 95% CI: 0.28-1.12) and SMI (OR 0.43, 95% CI: 0.21-0.88) had a significantly higher risk of skin lesions compared to their corresponding references after adjusting for occupation categories. The findings confirmed that inefficient arsenic methylation capacity was significantly associated with increased skin lesion risks and the effect might be modified by labour intensive occupations.

Keywords: Arsenicosis; Hyperpigmentation; Keratosis; Methylation capacity; Monomethylarsonic acid (MMA); Skin lesions.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Arsenic / metabolism*
Arsenic / toxicity
Cross-Sectional Studies
Drinking Water / adverse effects*
Environmental Exposure / adverse effects*
Female
Humans
Male
Middle Aged
Pakistan / epidemiology
Risk Factors
Rural Population / trends
Skin Diseases / chemically induced*
Skin Diseases / epidemiology
Skin Diseases / metabolism*
Water Pollutants, Chemical / metabolism*
Water Pollutants, Chemical / toxicity
Young Adult

Substances

Drinking Water
Water Pollutants, Chemical
Arsenic