Academic journal article Environmental Health Perspectives

Arsenic Reduction in Drinking Water and Improvement in Skin Lesions: A Follow-Up Study in Bangladesh

Academic journal article Environmental Health Perspectives

Arsenic Reduction in Drinking Water and Improvement in Skin Lesions: A Follow-Up Study in Bangladesh

Article excerpt

Globally, millions of people are exposed to arsenic from drinking contaminated water (Brammer and Ravenscroft 2009). Inorganic arsenic is classified as a Group 1 human carcinogen (International Agency for Research on Cancer 2004), and chronic exposure to arsenic in drinking water is associated with increased risk of skin, bladder, lung, and kidney cancer (Fernandez et al. 2012; Guo et al. 2001; Hopenhayn-Rich et al. 1998; Wu et al. 1989). Chronic exposure to arsenic is also associated with increased risk of skin lesions, cardiovascular diseases, lung function, hypertension, and reproductive and neurological disorders (Chattopadhyay et al. 2010; Chen et al. 2009; Milton et al. 2005; Rahman 2002).

Arsenic-contaminated groundwater in Bangladesh is a public health concern due to the use of shallow tube wells as part of a public health campaign to reduce the burden of waterborne diseases (Bagla and Kaiser 1996; Chakraborty and Saha 1987). It has been estimated that 45% of the population in Bangladesh was exposed to arsenic concentrations greater than the World Health Organization (WHO) recommended limit of 10 [micro]g/L, and 28% were exposed to concentrations greater than the Bangladesh standard of 50 [micro]g/L (Kinniburgh and Smedley 2001). Efforts to remediate arsenic-contaminated water in Bangladesh are ongoing and include testing tube wells, labeling unsafe wells, and installing new arsenic-free water sources and point-of-use filters (Joya et al. 2006; UNICEF 2008).

Skin lesions are the first visible symptom of chronic arsenic exposure (Chakraborty and Saha 1987; Rahman et al. 2001; Tseng et al. 1968) and are considered to be precursors of arsenic-induced cancers. These skin lesions are highly associated with skin cancers and other malignancies, and they are highly associated with arsenical skin cancers (Cuzick et al. 1982, 1984, 1992; Tseng 1977). Prospective cohort studies conducted in Bangladesh have provided good evidence that the incidence of skin lesions increases with arsenic levels over time (Argos et al. 2011), but few studies have examined whether skin lesions improve if arsenic exposures are reduced. In addition, most previous studies have evaluated the association between arsenic exposure and skin lesions as a dichotomous outcome only, without also considering the severity of skin lesions.

In 2009 we followed up individuals who participated in a case-control study of environmental and genetic risk factors for arsenic-related skin lesions in 2001-2003. Our main objective was to determine whether arsenic exposures decreased over time, and whether arsenic reduction was associated with a reduction in skin lesions. We estimated associations between changes in arsenic exposure and the prevalence and severity of skin lesions at follow-up among participants who had skin lesions at baseline.

Methods

Study population. In 2001-2003 (baseline), we enrolled 900 individuals who were diagnosed with arsenic-related skin lesions and 900 age- and sex-matched controls in Pabna, Bangladesh, into a case-control study to identify factors that influence susceptibility to arsenic-related skin lesions, as previously described by Breton et al. (2006). In a follow-up study during 2009-2011, 845 (93.9%) of the original 900 participants with skin lesions were successfully recontacted, and 550 cases (61.1% of the 900) agreed to participate in the follow-up study. Of those contacted, the main reasons for nonparticipation were refusal (53%), moved away from the district (38%), and mortality (9%).

All individuals in the baseline case-control study participated in Dhaka Community Hospital's arsenic awareness program, which provided information on the health effects of arsenic exposure, actions that individuals could take to reduce their exposure, and the importance of a diet rich in fruits and vegetables. Dhaka Community Hospital and their affiliated clinics also worked with impacted villages to install arsenic-free water sources through shallow dug wells, larger Indira wells, filtered surface water, and rainwater harvesting (Joya et al. …

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