Prevalence of arsenic exposure and skin lesions. A population based survey in Matlab, Bangladesh

Abstract

Study objective: To assess prevalence of arsenic exposure through drinking water and skin lesions, and their variation by geographical area, age, sex, and socioeconomic conditions. Design, setting, and participants: Skin lesion cases were identified by screening the entire population above 4 years of age (n = 166 934) living in Matlab, a rural area in Bangladesh, during January 2002 and August 2003. The process of case identification involved initial skin examinations in the field, followed by verification by physicians in a clinic, and final confirmation by two independent experts reviewing photographs. The tubewell water arsenic concentrations (n = 13 286) were analysed by atomic absorption spectrometry. Drinking water history since 1970 was obtained for each person. Exposure information was constructed using drinking water histories and data on water arsenic concentrations. Main results: The arsenic concentrations ranged from ,1 to 3644 mg/l, and more than 70% of functioning tubewells exceeded the World Health Organisation guideline of 10 mg/l. Arsenic exposure had increased steadily from 1970s to the late 1990s, afterwards a decrease could be noted. In total, 504 skin lesions cases were identified, and the overall crude prevalence was 3/1000. Women had significantly higher cumulative exposure to arsenic, while men had significantly higher prevalence of skin lesions (SMR 158, 95% CI 133 to 188). The highest prevalence occurred in 35-44 age groups for both sexes. Arsenic exposure and skin lesions had a positive association with socioeconomic groups and achieved educational level. Conclusions: The result showed sex, age, and socioeconomic differentials in both exposure and skin lesions. Findings clearly showed the urgency of effective arsenic mitigation activities.

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“…The U.S. Environmental Protection Agency maximal level for arsenic in drinking water is 10 ppb (% 130 nM). However, many populations in USA and elsewhere are exposed to unregulated drinking water sources that are in excess of 100 ppb (Rahman et al, 2006;Sherwood et al, 2013). The trivalent from of inorganic arsenic, arsenite (As þ3 ), has been associated with many diseases such as diabetes, skin lesions, and cancers (Argos et al, 2010;Schuhmacher-Wolz et al, 2009;Vahter, 2008).…”

Risk of arsenic-related skinlesions inBangladeshi villages at relatively low exposure: a report from Gonoshasthaya Kendra

“…9 We therefore examined this question using GK's plentiful data on social factors. It was not possible to do this for the villages individually, but we examined the main geographical groups to which our 53 villages belonged and selected as the best available index the proportion of pregnant women in the last two years classified as poor or very poor.…”

“…Whereas we relied on paramedics to describe objectively the results of simple inspection, other studies [4][5][6][7][8] have used physicians exercising their varying levels of judgement, and in one 9 (Matlab, Bangladesh) expert panels of physicians and dermatologists were used to reach consensus on the diagnosis of arsenical keratosis. This resulted in rejection of 70% of cases reported by the field workers.…”

“…Two studies [6][7] reported very low risks below 50mg/L, rising to prevalences of 20-30% at higher concentrations. The two remaining studies by Ahsan et al 8 and Rahman et al 9 published in 2006 were both large and from circumscribed areas south-east of Dhaka, where arsenic contaminations are high. The former study, in Araihazar, reported a systematic increase in prevalence odds ratios (OR) compared to those in drinking water containing <8.1mg/L, of 1.91 at 8.1-40mg/L, rising to 5.39 at > 175.1mg/L.…”

“…There have been five recent prevalence studies: one in West Bengal, 4 later used in a case-control analysis, 5 and four in Bangladesh, [6][7][8][9] where exposures estimated individually were related to risk of skin lesions. Two studies [6][7] reported very low risks below 50mg/L, rising to prevalences of 20-30% at higher concentrations.…”