Elevated urine arsenic: un-speciated results lead to unnecessary concern and further evaluations.
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The consumption of seafood within two to three days of testing can increase total urine arsenic concentrations. Few clinicians are familiar with this fact and often misinterpret elevated results. A retrospective chart review of all cases with arsenic testing seen between 1991 and 2004 at an occupational and environmental medicine referral clinic was performed. Urine arsenic results were classified as follows: total arsenic levels; speciated results (inorganic, ionic arsenic); and whether the patient abstained from seafood prior to the collection. Laboratory detection limits for total and for ionic arsenic were < or = 2 microg/L. Fifty-four patients with urine arsenic testing were identified. The total urine arsenic concentration exceeded 40 microg/L for 28 patients. On paired, speciated testing (n = 21), mean total arsenic was 122 +/- 227 microg/L, and ionic arsenic was not detected in any of these same samples (p = 0.023). On paired testing, before and after seafood abstention (n = 12), total urine arsenic without abstention was 291 +/- 267 microg/L, and it was only 9 +/- 12 microg/L after seafood abstention (p = 0.004). The total urine arsenic elevations observed in our series were due to benign organic arsenic compounds commonly found in seafood. Laboratories should reflexively perform speciation on most samples with elevated total arsenic concentrations prior to reporting the results. Reflexive speciation could reduce unnecessary referrals, further testing, and patient anxiety. (+info)
Association of clinical complications with nutritional status and the prevalence of leukopenia among arsenic patients in Bangladesh.
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This study conducted in Bangladesh reports the relationship of clinical complications with nutritional status and the prevalence of leukopenia among arsenic exposed patients living in the rural villages. A total of 115 exposed individuals diagnosed as arsenicosis patients were randomly selected from four known arsenic endemic villages, and age-matched 120 unexposed subjects were enrolled in the study program. The duration of arsenic exposure in about 37% of the patients was at least 10 yrs, while the population mean and range were 7.6 +/- 5.2 yrs, and 1 - 25 yrs, respectively. The mean arsenic concentrations in the drinking water for the exposed and unexposed (control) population were 218.1 microg/L and 11.3 microg/L, respectively. The spot urine sample of the arsenicosis patients contained an average of 234.6 microg/L arsenic. Although very few patients showed elevated WBC count, 16% had leukopenia (below normal count), and the whole population had significantly low WBC count than the control subjects. Prevalences of neutropenia and lymphocytosis were observed in patients with chronic exposure to high levels of arsenic in water. The body mass index was found to be lower than 18.5, the cut-off point for malnutrition (underweight), in about 28% of the arsenicosis cases compared to 15% of the controls. The monthly income and total calorie consumption per day showed the patients were underprivileged than the controls. Arsenical symptoms and complications were more severe in the nutritionally vulnerable (underweight) patients than the overweight ones. Also, the incidences of leukopenia and anaemia were more common in the female patients who were underweight. The findings of this research demonstrate that the poor nutritional status of patients increases the complications of chronic arsenic toxicity; suggest the possibility of other sources of arsenic contamination different from drinking water in the study area; and establish a higher prevalence of leukopenia and lymphocytosis in arsenicosis patients. (+info)
Gender-specific protective effect of hemoglobin on arsenic-induced skin lesions.
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Chronic arsenic poisoning remains a public health crisis in Bangladesh. As arsenic has been shown to bind to human hemoglobin (Hb), hematologic mechanisms may play a role in the pathway through which arsenic exerts its toxicity. Two separate studies, a case-control and a cohort, were conducted to investigate the role of Hb in the development of arsenic-induced skin lesions. In the first, conditional logistic regression was used to investigate the effect of Hb on skin lesions among 900 case-control pairs from Pabna, Bangladesh, in which individuals were matched on gender, age, and location. In the second, mixed linear regression models were used to examine the association between toenail arsenic, urinary arsenic, and Hb within a cohort of 184 individuals from 50 families in the same region who did not have arsenic-induced skin lesions. Hb was significantly associated with skin lesions but this association was gender specific. In males, a 40% reduction in the odds of skin lesions occurred for every 1 g/dL increase in Hb (odds ratio, 0.60; 95% confidence interval, 0.49-0.73). No effect was observed for females (odds ratio, 1.16; 95% confidence interval, 0.92-1.46). In the cohort of 184 individuals, no associations between toenail arsenic or urinary arsenic species and Hb levels were observed. Low Hb levels may exacerbate the detrimental health effects of chronic arsenic poisoning. Whereas providing clean water remains the optimal solution to Bangladesh's problem of arsenic poisoning, improving nutrition and reducing iron-deficiency anemia may ameliorate negative health effects, such as skin lesions in individuals who have been exposed. (+info)
Assessment of arsenic contamination of groundwater and health problems in Bangladesh.
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Excessive amounts of arsenic (As) in the groundwater in Bangladesh and neighboring states in India are a major public health problem. About 30% of the private wells in Bangladesh exhibit high concentrations of arsenic. Over half the country, 269 out of 464 administrative units, is affected. Similar problems exist in many other parts of the world, including the Unites States. This paper presents an assessment of the health hazards caused by arsenic contamination in the drinking water in Bangladesh. Four competing hypotheses, each addressing the sources, reaction mechanisms, pathways, and sinks of arsenic in groundwater, were analyzed in the context of the geologic history and land-use practices in the Bengal Basin. None of the hypotheses alone can explain the observed variability in arsenic concentration in time and space; each appears to have some validity on a local scale. Thus, it is likely that several biogeochemical processes are active among the region's various geologic environments, and that each contributes to the mobilization and release of arsenic. Additional research efforts will be needed to understand the relationships between underlying biogeochemical factors and the mechanisms for arsenic release in various geologic settings. (+info)
Evaluation of biochemical changes in chronic arsenic poisoning among Bangladeshi patients.
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An estimated 40 million people in Bangladesh have been suffering from arsenic toxicity-related diseases because of drinking water contamination with high levels of naturally occurring arsenic. To evaluate the biochemical changes in chronic arsenic exposure, a total of 115 exposed subjects diagnosed as arsenicosis patients were examined and interviewed, and 120 unexposed volunteers were enrolled in this study. Drinking water, urine and peripheral blood samples were collected from all participants and analyzed. The average levels of arsenic in the drinking water and spot urine samples of the arsenicosis patients were 218.1 microg/L and 234.6 microg/L, respectively, and duration of exposure was 7.6 +/- 5.2 yrs that ranged from 1-25 yrs. Prevalence of diabetes mellitus among chronic arsenic-exposed subjects was about 2.8 times higher than the unexposed subjects. The activities of alkaline phosphatase were significantly elevated in the patients, 197 U/L compared to 149 U/L in the controls, but alanine transaminase and aspartate transaminase were mostly normal. The patients had significantly lower levels of serum creatinine, 0.97 mg/dL compared to 1.15 mg/dL in the controls; but had significantly elevated levels of total protein, 84 g/L and 77 g/L respectively. The mean level of inorganic phosphate in the serum of arsenicosis patients was 6.4 mg/dL compared to 4.6 mg/dL in the unexposed subjects and the level was significantly higher, indicating substitution of the pentavalent arsenate for the phosphate ion causing underutilization of the latter. Evaluation of the lipid profiles showed while the levels of triacylglycerol were not much different, the patients had significantly lower levels of cholesterol, HDL-cholesterol and LDL-cholesterol compared to the unexposed subjects. These findings suggest significant changes in biochemical parameters in human arsenic toxicity. (+info)
Arsenic cancer risk confounder in southwest Taiwan data set.
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Quantitative analysis for the risk of human cancer from the ingestion of inorganic arsenic has been based on the reported cancer mortality experience in the blackfoot disease (BFD) -endemic area of southwest Taiwan. Linear regression analysis shows that arsenic as the sole etiologic factor accounts for only 21% of the variance in the village standardized mortality ratios for bladder and lung cancer. A previous study had reported the influence of confounders (township, BFD prevalence, and artesian well dependency) qualitatively, but they have not been introduced into a quantitative assessment. In this six-township study, only three townships (2, 4, and 6) showed a significant positive dose-response relationship with arsenic exposure. The other three townships (0, 3, and 5) demonstrated significant bladder and lung cancer risks that were independent of arsenic exposure. The data for bladder and lung cancer mortality for townships 2, 4, and 6 fit an inverse linear regression model (p < 0.001) with an estimated threshold at 151 microg/L (95% confidence interval, 42 to 229 microg/L) . Such a model is consistent with epidemiologic and toxicologic literature for bladder cancer. Exploration of the southwest Taiwan cancer mortality data set has clarified the dose-response relationship with arsenic exposure by separating out township as a confounding factor. Key words: arsenic, blackfoot disease, bladder cancer, cancer risk, confounder, dose-response relationship, southwest Taiwan, threshold model. (+info)
Gene expression profiles in peripheral lymphocytes by arsenic exposure and skin lesion status in a Bangladeshi population.
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Millions of individuals worldwide are chronically exposed to arsenic through their drinking water. In this study, the effect of arsenic exposure and arsenical skin lesion status on genome-wide gene expression patterns was evaluated using RNA from peripheral blood lymphocytes of individuals selected from the Health Effects of Arsenic Longitudinal Study. Affymetrix HG-U133A GeneChip (Affymetrix, Santa Clara, CA) arrays were used to measure the expression of approximately 22,000 transcripts. Our primary statistical analysis involved identifying differentially expressed genes between participants with and without arsenical skin lesions based on the significance analysis of microarrays statistic with an a priori defined 1% false discovery rate to minimize false positives. To better characterize differential expression, we also conducted Gene Ontology and pathway comparisons in addition to the gene-specific analyses. Four-hundred sixty-eight genes were differentially expressed between these two groups, from which 312 differentially expressed genes were identified by restricting the analysis to female never-smokers. We also explored possible differential gene expression by arsenic exposure levels among individuals without manifest arsenical skin lesions; however, no differentially expressed genes could be identified from this comparison. Our findings show that microarray-based gene expression analysis is a powerful method to characterize the molecular profile of arsenic exposure and arsenic-induced diseases. Genes identified from this analysis may provide insights into the underlying processes of arsenic-induced disease and represent potential targets for chemoprevention studies to reduce arsenic-induced skin cancer in this population. (+info)
Arsine toxicity aboard the Asiafreighter.
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Eight sailors on board the Asiafreighter were exposed to arsine that had escaped from a cylinder in the cargo hold. Four suffered severe toxicity and within a few hours had developed fever, weakness, nausea, vomiting, diarrhoea, abdominal pain, and haemoglobinuria. These patients had pronounced intravascular haemolysis, which in one patient was complete. This patient was also stuporose and anoxic, a condition attributed to failure of oxygen transport and sludging of red cell debris in the cerebral and pulmonary circulations, but he regained a normal level of consciousness after exchange transfusion. Evidence of marrow depression was present: the reticulocyte response to the haemolysis was poor and there was a thrombocytopenia. All four patients developed renal failure, one being totally anuric for five weeks. Two patients developed peripheral neuropathy, and one was still severely disabled six months after the incident. The other four patients had a similar, though less severe, illness. (+info)