Health Impact of Early Life Exposure to Arsenic
Health Impacts of Early Life Exposure to Arsenic
Allan Smith, Professor of Epidemiology and Arsenic Health Effects Research Group, University of California, Berkeley, U.S.A, (firstname.lastname@example.org)
spoke on the health impacts of early life exposure to arsenic.
One sign of arsenic poisoning which appears sometimes in children exposed for many years is skin lesions with the unique characteristic of areas of hyperpigmentation alternating with areas of hypopigmentation (Figure 9.3).
The effect of chronic arsenic exposure on child development has been evaluated using intelligence tests designed for children in developing countries:
- A study in Thailand (Figure 9.4) suggested a relationship between elevated arsenic levels in hair and developmental retardation;
- Dr. Smith and colleagues performed a study in West Bengal, India which showed a relationship between urinary arsenic levels and intellectual development (Figure 9.5);
- A study in Bangladesh showed a relationship between arsenic exposure and intellectual function (Figure 9.6).
The conclusions from these studies are shown in Figure 9.7.
Dr. Smith posed the question: Can early life (in utero, or in childhood) exposure to arsenic result in adult disease?
To answer this question, Dr. Smith described studies which were performed in a region of Chile where an entire population had been exposed, for approximately 13 years (from 1958-1970), to high concentrations of arsenic in their drinking water (Figure 9.8). Follow up studies done from 1989-1993 revealed a high incidence of lung cancer, especially in young men 23-30 years of age (Figure 9.9). The risk of lung cancer from childhood exposure to arsenic, relative to exposure to atomic bomb radiation and second hand tobacco smoke exposure is shown in Figure 9.10.
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Exposure to arsenic also related to a predisposition to develop other forms of cancer; the excess deaths in the Chilean study due to arsenic exposure is shown in Figure 9.11.
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In addition to cancer there was a high incidence of chronic obstructive pulmonary disease and/or bronchiectasis in young men who had been exposed to high levels of arsenic as infants or in utero.
Thus, arsenic exposure in early childhood affects not only development but also creates a predisposition for developing adult disease (Figure 9.12)
More study is required but in the meantime arsenic exposure should be prevented (Figure 9.13). Dr. Smith cited one approach now being applied in India where wells are made shallow so as to avoid arsenic contamination that occurs with deeper wells.