Socioeconomic status and the association between arsenic exposure and type 2 diabetes.

OBJECTIVE: Evaluate whether arsenic-related diabetes risks differ between people of low and high socioeconomic status (SES). METHODS: We used data collected between October 2007-December 2010 from a population-based cancer case-control study (N = 1301) in Northern Chile, an area with high arsenic water concentrations (>800 µg/L) and comprehensive records of past exposure. Information on lifetime exposure and potential confounders were obtained using structured interviews, questionnaires, and residential histories. Type 2 diabetes was defined as physician-diagnosed diabetes or oral hypoglycemic medication use. SES was measured using a 14-point scale based on ownership of household appliances, cars, internet access, or use of domestic help. Logistic regression was used to assess the relationship between arsenic and diabetes within strata of SES. RESULTS: Among those with low SES, the odds ratio (OR) for diabetes comparing individuals in the highest to lowest tertile of lifetime average arsenic exposure was 2.12 (95% confidence interval (CI) 1.29-3.49, p = 0.004). However, those in the high SES group were not at increased risk (OR = 1.12 [95% CI = 0.72-1.73]). CONCLUSIONS: Our findings provide evidence that risks of arsenic-related diabetes may be higher in Chile in people with low versus high SES.

Age at Exposure to Arsenic in Water and Mortality 30-40 Years After Exposure Cessation.

Arsenic in drinking water is known to cause cancer and noncancer diseases, but little is known about its association with age at exposure. Here, we investigated age at arsenic exposure and mortality in Antofagasta, Chile, 30-40 years after a distinct period of very high water arsenic concentrations (1958-1970). We calculated standardized mortality ratios (SMRs) comparing Antofagasta with the rest of Chile for 2001-2010 by sex and age at potential first exposure. A remarkable relationship with age at first exposure was found for bronchiectasis, with increased risk in adults 30-40 years after exposure being confined to those who were in utero (SMR = 11.7, 95% confidence interval (CI): 4.3, 25.4) or aged 1-10 years (SMR = 5.4, 95% CI: 1.1, 15.8) during the high-exposure period. Increased SMRs for lung, bladder, and laryngeal cancer were evident for exposures starting at all ages, but the highest SMRs were for exposures beginning at birth (for bladder cancer, SMR = 16.0 (95% CI: 10.3, 23.8); for laryngeal cancer, SMR = 6.8 (95% CI: 2.2, 15.8); for lung cancer, SMR = 3.8 (95% CI: 2.9, 4.9)). These findings suggest that interventions targeting early-life arsenic exposure could have major impacts in reducing long-term mortality due to arsenic 30-40 years after exposure ends.

Obesity and increased susceptibility to arsenic-related type 2 diabetes in Northern Chile.

BACKGROUND: The prevalence of type 2 diabetes (T2D) has nearly doubled since 1980. Elevated body mass index (BMI) is the leading risk factor for T2D, mediated by inflammation and oxidative stress. Arsenic shares similar pathogenic processes, and may contribute to hyperglycemia and ß-cell dysfunction. OBJECTIVES: We assessed a unique situation of individuals living in Northern Chile with data on lifetime arsenic exposure to evaluate the relationship between arsenic and T2D, and investigate possible interactions with BMI. METHODS: We analyzed data collected from October 2007-December 2010 from an arsenic-cancer case-control study. Information on self-reported weight, height, smoking, diet, and other factors were obtained. Diabetes was defined by self-reported physician-diagnoses or use of hypoglycemic medication. A total of 1053 individuals, 234 diabetics and 819 without known diabetes were included. RESULTS: The T2D odds ratio (OR) for cumulative arsenic exposures of 610-5279 and ≥ 5280 µg/L-years occurring 40 years or more before interview were 0.97 (95% CI: 0.66-1.43) and 1.53 (95% CI: 1.05-2.23), respectively. Arsenic-associated T2D ORs were greater in subjects with increased BMIs. For example, the ORs for past cumulative exposures ≥ 5280 µg/L-years was 1.45 (95% CI: 0.74-2.84) in participants with BMIs < 25 kg/m2 but 2.64 (95% CI: 1.14-6.11) in those with BMIs ≥ 30 kg/m2 (synergy index = 2.49, 95% CI: 0.87-7.09). Results were similar when people with cancer were excluded. CONCLUSIONS: These findings identify increased odds of T2D with arsenic exposure, which are significantly increased in individuals with excess BMI.

Sex ratio of the offspring of New Zealand phenoxy herbicide producers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

OBJECTIVES: Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has inconsistently been associated with a decreased sex ratio of the offspring (number of male births divided by total births). We conducted a study among men and women who were employed in a New Zealand phenoxy herbicide production plant between 1969 and 1984, to study their offspring sex ratio in relation to their back-calculated TCDD serum concentrations determined in 2007/2008. METHODS: A total of 127 men and 21 women reported that 355 children were conceived after starting employment at the plant. The association between their lipid-standardised TCDD serum concentrations back-calculated to the time of their offspring's birth and the probability of a male birth was estimated through logistic regression, adjusting for the age of the exposed parent at birth, current body mass index and smoking. RESULTS: The overall sex ratio was 0.55 (197 boys, 158 girls). For fathers with serum TCDD concentrations ≥20 pg/g lipid at time of birth, the sex ratio was 0.47 (OR 0.49; 95% CI 0.30 to 0.79). The probability of a male birth decreased with higher paternal serum TCDD at time of birth (<4; 4-20; 20-100; ≥100 pg/g lipid), with ORs of 1.00 (reference); 1.00 (95% CI 0.50 to 2.02); 0.52 (95% CI 0.29 to 0.92); 0.45 (95% CI 0.23 to 0.89), p trend 0.007. For exposed mothers, the sex ratio was not reduced. CONCLUSIONS: This study indicates that paternal serum TCDD concentrations in excess of an estimated 20 pg/g lipid at time of conception are associated with a reduced sex ratio.

The impact of BMI on non-malignant respiratory symptoms and lung function in arsenic exposed adults of Northern Chile.

BACKGROUND: Elevated body mass index (BMI) and arsenic are both associated with cancer and with non-malignant lung disease. Using a unique exposure situation in Northern Chile with data on lifetime arsenic exposure, we previously identified the first evidence of an interaction between arsenic and BMI for the development of lung cancer. OBJECTIVES: We examined whether there was an interaction between arsenic and BMI for the development of non-malignant lung disease. METHODS: Data on lifetime arsenic exposure, respiratory symptoms, spirometry, BMI, and smoking were collected from 751 participants from cities in Northern Chile with varying levels of arsenic water concentrations. Spirometry values and respiratory symptoms were compared across subjects in different categories of arsenic exposure and BMI. RESULTS: Adults with both a BMI above the 90th percentile (>33.9kg/m2) and arsenic water concentrations ≥11µg/L exhibited high odds ratios (ORs) for cough (OR = 10.7, 95% confidence interval (CI): 3.03, 50.1), shortness of breath (OR = 14.2, 95% CI: 4.79, 52.4), wheeze (OR = 14.4, 95% CI: 4.80, 53.7), and the combined presence of any respiratory symptom (OR = 9.82, 95% CI: 4.22, 24.5). In subjects with lower BMIs, respiratory symptom ORs for arsenic water concentrations ≥11µg/L were markedly lower. In never-smokers, reductions in forced vital capacity associated with arsenic increased as BMI increased. Analysis of the FEV1/FVC ratio in never-smokers significantly increased as BMI and arsenic concentrations increased. Similar trends were not observed for FEV1 alone or in ever-smokers. CONCLUSIONS: This study provides preliminary evidence that BMI may increase the risk for arsenic-related non-malignant respiratory disease.

Hypertension among adults exposed to drinking water arsenic in Northern Chile.

BACKGROUND: A growing number of studies have identified an association between exposure to inorganic arsenic and hypertension. However, results have not been consistent across studies. Additional studies are warranted, given the global prevalence of both arsenic exposure and morbidity attributable to hypertension. METHODS: We analyzed data collected from October 2007-December 2010 for a population-based cancer case-control study in northern Chile. Data included lifetime individual arsenic exposure estimates and information on potential confounders for a total of 1266 subjects. Those self-reporting either a physician diagnosis of hypertension or use of an anti-hypertensive medication were classified as having hypertension (n=612). The association between hypertension and drinking water arsenic exposure was analyzed using logistic regression models. RESULTS: Compared to those in the lowest category for lifetime highest 5-year average arsenic exposure (<60µg/L), those in the middle (60-623µg/L) and upper (>623µg/L) exposure categories had adjusted hypertension ORs of 1.49 (95% CI: 1.09, 2.05) and 1.65 (95% CI: 1.18, 2.32), respectively. Similar results were observed in analyses of lifetime cumulative exposures and analyses restricted to exposures from the distant past. CONCLUSIONS: We identified evidence of increased odds of hypertension with exposure to arsenic in drinking water among study participants. Our findings add to the growing body of research supporting this association, which could have important public health implications.

High risks of lung disease associated with early-life and moderate lifetime arsenic exposure in northern Chile.

BACKGROUND: Arsenic in drinking water has been associated with increases in lung disease, but information on the long-term impacts of early-life exposure or moderate exposure levels are limited. METHODS: We investigated pulmonary disease and lung function in 795 subjects from three socio-demographically similar areas in northern Chile: Antofagasta, which had a well-described period of high arsenic water concentrations (860µg/L) from 1958 to 1970; Iquique, which had long-term arsenic water concentrations near 60µg/L; and Arica, with long-term water concentrations ≤10µg/L. RESULTS: Compared to adults never exposed >10µg/L, adults born in Antofagasta during the high exposure period had elevated odds ratios (OR) of respiratory symptoms (e.g., OR for shortness of breath=5.56, 90% confidence interval (CI): 2.68-11.5), and decreases in pulmonary function (e.g., 224mL decrease in forced vital capacity in nonsmokers, 90% CI: 97-351mL). Subjects with long-term exposure to arsenic water concentrations near 60µg/L also had increases in some pulmonary symptoms and reduced lung function. CONCLUSIONS: Overall, these findings provide new evidence that in utero or childhood arsenic exposure is associated with non-malignant pulmonary disease in adults. They also provide preliminary new evidence that long-term exposures to moderate levels of arsenic may be associated with lung toxicity, although the magnitude of these latter findings were greater than expected and should be confirmed.

Obesity and excess weight in early adulthood and high risks of arsenic-related cancer in later life.

BACKGROUND: Elevated body mass index (BMI) is a risk factor for cardiovascular disease, diabetes, cancer, and other diseases. Inflammation or oxidative stress induced by high BMI may explain some of these effects. Millions of people drink arsenic-contaminated water worldwide, and ingested arsenic has also been associated with inflammation, oxidative stress, and cancer. OBJECTIVES: To assess the unique situation of people living in northern Chile exposed to high arsenic concentrations in drinking water and investigate interactions between arsenic and BMI, and associations with lung and bladder cancer risks. METHODS: Information on self-reported body mass index (BMI) at various life stages, smoking, diet, and lifetime arsenic exposure was collected from 532 cancer cases and 634 population-based controls. RESULTS: In subjects with BMIs <90th percentile in early adulthood (27.7 and 28.6 kg/m(2) in males and females, respectively), odds ratios (OR) for lung and bladder cancer combined for arsenic concentrations of <100, 100-800 and >800 µg/L were 1.00, 1.64 (95% CI, 1.19-2.27), and 3.12 (2.30-4.22). In subjects with BMIs ≥90th percentile in early adulthood, the corresponding ORs were higher: 1.00, 1.84 (0.75-4.52), and 9.37 (2.88-30.53), respectively (synergy index=4.05, 95% CI, 1.27-12.88). Arsenic-related cancer ORs >20 were seen in those with elevated BMIs in both early adulthood and in later life. Adjustments for smoking, diet, and other factors had little impact. CONCLUSION: These findings provide novel preliminary evidence supporting the notion that environmentally-related cancer risks may be markedly increased in people with elevated BMIs, especially in those with an elevated BMI in early-life.

Elevated lung cancer in younger adults and low concentrations of arsenic in water.

Arsenic concentrations greater than 100 µg/L in drinking water are a known cause of cancer, but the risks associated with lower concentrations are less well understood. The unusual geology and good information on past exposure found in northern Chile are key advantages for investigating the potential long-term effects of arsenic. We performed a case-control study of lung cancer from 2007 to 2010 in areas of northern Chile that had a wide range of arsenic concentrations in drinking water. Previously, we reported evidence of elevated cancer risks at arsenic concentrations greater than 100 µg/L. In the present study, we restricted analyses to the 92 cases and 288 population-based controls who were exposed to concentrations less than 100 µg/L. After adjustment for age, sex, and smoking behavior, these exposures from 40 or more years ago resulted in odds ratios for lung cancer of 1.00, 1.43 (90% confidence interval: 0.82, 2.52), and 2.01 (90% confidence interval: 1.14, 3.52) for increasing tertiles of arsenic exposure, respectively (P for trend = 0.02). Mean arsenic water concentrations in these tertiles were 6.5, 23.0, and 58.6 µg/L. For subjects younger than 65 years of age, the corresponding odds ratios were 1.00, 1.62 (90% confidence interval: 0.67, 3.90), and 3.41 (90% confidence interval: 1.51, 7.70). Adjustments for occupation, fruit and vegetable intake, and socioeconomic status had little impact on the results. These findings provide new evidence that arsenic water concentrations less than 100 µg/L are associated with higher risks of lung cancer.

Arsenic methylation and lung and bladder cancer in a case-control study in northern Chile.

In humans, ingested inorganic arsenic is metabolized to monomethylarsenic (MMA) then to dimethylarsenic (DMA), although this process is not complete in most people. The trivalent form of MMA is highly toxic in vitro and previous studies have identified associations between the proportion of urinary arsenic as MMA (%MMA) and several arsenic-related diseases. To date, however, relatively little is known about its role in lung cancer, the most common cause of arsenic-related death, or about its impacts on people drinking water with lower arsenic concentrations (e.g., <200µg/L). In this study, urinary arsenic metabolites were measured in 94 lung and 117 bladder cancer cases and 347 population-based controls from areas in northern Chile with a wide range of drinking water arsenic concentrations. Lung cancer odds ratios adjusted for age, sex, and smoking by increasing tertiles of %MMA were 1.00, 1.91 (95% confidence interval (CI), 0.99-3.67), and 3.26 (1.76-6.04) (p-trend <0.001). Corresponding odds ratios for bladder cancer were 1.00, 1.81 (1.06-3.11), and 2.02 (1.15-3.54) (p-trend <0.001). In analyses confined to subjects only with arsenic water concentrations <200µg/L (median=60µg/L), lung and bladder cancer odds ratios for subjects in the upper tertile of %MMA compared to subjects in the lower two tertiles were 2.48 (1.08-5.68) and 2.37 (1.01-5.57), respectively. Overall, these findings provide evidence that inter-individual differences in arsenic metabolism may be an important risk factor for arsenic-related lung cancer, and may play a role in cancer risks among people exposed to relatively low arsenic water concentrations.

Efficacy of isoniazid prophylactic therapy in prevention of tuberculosis in children: a meta-analysis.

BACKGROUND: Children are highly susceptible to tuberculosis; thus, there is need for safe and effective preventive interventions. Our objective was to evaluate the efficacy of isoniazid in prevention of tuberculosis morbidity and mortality in children aged 15 years or younger by performing a meta-analysis of randomized controlled trials. To our knowledge, this is the first meta-analysis evaluating efficacy of isoniazid prophylaxis in prevention of tuberculosis in children. METHODS: A systematic search of the literature was done to identify randomized controlled trials evaluating isoniazid prophylaxis efficacy among children. Each study was evaluated for relevance and validity for inclusion in the analysis. Subgroup analyses were conducted based on study quality, HIV status, tuberculosis endemicity, type of prophylaxis and age of participants. RESULTS: Eight studies comprising 10,320 participants were included in this analysis. Upon combining data from all eight studies, isoniazid prophylaxis was found to be efficacious in preventing development of tuberculosis, with a pooled RR of 0.65 (95% CI 0.47, 0.89) p = 0.004 , with confidence intervals adjusted for heterogeneity. Among the sub-group analyses conducted, only age of the participants yielded dramatic differences in the summary estimate of efficacy, suggesting that age might be an effect modifier of the efficacy of isoniazid among children, with no effect realised in children initiating isoniazid at four months of age or earlier and an effect being present in older children. Excluding studies in which isoniazid was initiated at four months of age or earlier yielded an even stronger effect (RR = 0.41 (95% CI 0.31, 0.55) p <0.001). Data on the effect of isoniazid on all-cause mortality, excluding studies in which isoniazid was initiated in infants, yielded an imprecise estimate of mortality benefit (RR = 0.58 (95% CI 0.31, 1.09) p = 0.092). CONCLUSION: Isoniazid prophylaxis reduces the risk of developing tuberculosis by 59% among children aged 15 years or younger excluding children initiated during early infancy for primary prophylaxis (RR = 0.41, 95% CI 0.31, 0.55 p < 0.001) . However, further studies are needed to assess effects on mortality and to determine prophylaxis effectiveness in very young children and among HIV-infected children.

Case-control study of arsenic in drinking water and kidney cancer in uniquely exposed Northern Chile.

Millions of people worldwide are exposed to arsenic in drinking water. The International Agency for Research on Cancer has concluded that ingested arsenic causes lung, bladder, and skin cancer. However, a similar conclusion was not made for kidney cancer because of a lack of research with individual data on exposure and dose-response. With its unusual geology, high exposures, and good information on past arsenic water concentrations, northern Chile is one of the best places in the world to investigate the carcinogenicity of arsenic. We performed a case-control study in 2007-2010 of 122 kidney cancer cases and 640 population-based controls with individual data on exposure and potential confounders. Cases included 76 renal cell, 24 transitional cell renal pelvis and ureter, and 22 other kidney cancers. For renal pelvis and ureter cancers, the adjusted odds ratios by average arsenic intakes of <400, 400-1,000, and >1,000 µg/day (median water concentrations of 60, 300, and 860 µg/L) were 1.00, 5.71 (95% confidence interval: 1.65, 19.82), and 11.09 (95% confidence interval: 3.60, 34.16) (Ptrend < 0.001), respectively. Odds ratios were not elevated for renal cell cancer. With these new findings, including evidence of dose-response, we believe there is now sufficient evidence in humans that drinking-water arsenic causes renal pelvis and ureter cancer.

Arsenic, tobacco smoke, and occupation: associations of multiple agents with lung and bladder cancer.

BACKGROUND: Millions of people worldwide are exposed to arsenic in drinking water, and many are likely coexposed to other agents that could substantially increase their risks of arsenic-related cancer. METHODS: We performed a case-control study of multiple chemical exposures in 538 lung and bladder cancer cases and 640 controls in northern Chile, an area with formerly high drinking water arsenic concentrations. Detailed information was collected on lifetime arsenic exposure, smoking, secondhand smoke, and other known or suspected carcinogens, including asbestos, silica, and wood dust. RESULTS: Very high lung and bladder cancer odds ratios (ORs), and evidence of greater than additive effects, were seen in people exposed to arsenic concentrations >335 µg/L and who were tobacco smokers (OR = 16, 95% confidence interval = 6.5-40 for lung cancer; and OR = 23 [8.2-66] for bladder cancer; Rothman Synergy Indices = 4.0 [1.7-9.4] and 2.0 [0.92-4.5], respectively). Evidence of greater than additive effects were also seen in people coexposed to arsenic and secondhand tobacco smoke and several other known or suspected carcinogens, including asbestos, silica, and wood dust. CONCLUSIONS: These findings suggest that people coexposed to arsenic and other known or suspected carcinogens have very high risks of lung or bladder cancer.

Combined effects of perchlorate, thiocyanate, and iodine on thyroid function in the National Health and Nutrition Examination Survey 2007-08.

Perchlorate, thiocyanate, and low iodine intake can all decrease iodide intake into the thyroid gland. This can reduce thyroid hormone production since iodide is a key component of thyroid hormone. Previous research has suggested that each of these factors alone may decrease thyroid hormone levels, but effect sizes are small. We hypothesized that people who have all three factors at the same time have substantially lower thyroid hormone levels than people who do not, and the effect of this combined exposure is substantially larger than the effects seen in analyses focused on only one factor at a time. Using data from the 2007-2008 National Health and Nutrition Examination Survey, subjects were categorized into exposure groups based on their urinary perchlorate, iodine, and thiocyanate concentrations, and mean serum thyroxine concentrations were compared between groups. Subjects with high perchlorate (n=1939) had thyroxine concentrations that were 5.0% lower (mean difference=0.40 µg/dl, 95% confidence interval=0.14-0.65) than subjects with low perchlorate (n=2084). The individual effects of iodine and thiocyanate were even smaller. Subjects with high perchlorate, high thiocyanate, and low iodine combined (n=62) had thyroxine concentrations 12.9% lower (mean difference=1.07 µg/dl, 95% confidence interval=0.55-1.59) than subjects with low perchlorate, low thiocyanate, and adequate iodine (n=376). Potential confounders had little impact on results. Overall, these results suggest that concomitant exposure to perchlorate, thiocyanate, and low iodine markedly reduces thyroxine production. This highlights the potential importance of examining the combined effects of multiple agents when evaluating the toxicity of thyroid-disrupting agents.

Evidence from Chile that arsenic in drinking water may increase mortality from pulmonary tuberculosis.

Arsenic in drinking water causes increased mortality from several cancers, ischemic heart disease, bronchiectasis, and other diseases. This paper presents the first evidence relating arsenic exposure to pulmonary tuberculosis, by estimating mortality rate ratios for Region II of Chile compared with Region V for the years 1958-2000. The authors compared mortality rate ratios with time patterns of arsenic exposure, which increased abruptly in 1958 in Region II and then declined starting in 1971. Tuberculosis mortality rate ratios in men started increasing in 1968, 10 years after high arsenic exposure commenced. The peak male 5-year mortality rate ratio occurred during 1982-1986 (rate ratio = 2.1, 95% confidence interval: 1.7, 2.6; P < 0.001) and subsequently declined. Mortality rates in women were also elevated but with fewer excess pulmonary tuberculosis deaths (359 among men and 95 among women). The clear rise and fall of tuberculosis mortality rate ratios in men following high arsenic exposure are consistent with a causal relation. The findings are biologically plausible in view of evidence that arsenic is an immunosuppressant and also a cause of chronic lung disease. Finding weaker associations in women is unsurprising, because this is true of most arsenic-caused health effects. Confirmatory evidence is needed from other arsenic-exposed populations.

Data sharing: not as simple as it seems.

In recent years there has been a major change on the part of funders, particularly in North America, so that data sharing is now considered to be the norm rather than the exception. We believe that data sharing is a good idea. However, we also believe that it is inappropriate to prescribe exactly when or how researchers should preserve and share data, since these issues are highly specific to each study, the nature of the data collected, who is requesting it, and what they intend to do with it. The level of ethical concern will vary according to the nature of the information, and the way in which it is collected - analyses of anonymised hospital admission records may carry a quite different ethical burden than analyses of potentially identifiable health information collected directly from the study participants. It is striking that most discussions about data sharing focus almost exclusively on issues of ownership (by the researchers or the funders) and efficiency (on the part of the funders). There is usually little discussion of the ethical issues involved in data sharing, and its implications for the study participants. Obtaining prior informed consent from the participants does not solve this problem, unless the informed consent process makes it completely clear what is being proposed, in which case most study participants would not agree. Thus, the undoubted benefits of data sharing does not remove the obligations and responsibilities that the original investigators hold for the people they invited to participate in the study.

Lung function in adults following in utero and childhood exposure to arsenic in drinking water: preliminary findings.

PURPOSE: Evidence suggests that arsenic in drinking water causes non-malignant lung disease, but nearly all data concern exposed adults. The desert city of Antofagasta (population 257,976) in northern Chile had high concentrations of arsenic in drinking water (>800 µg/l) from 1958 until 1970, when a new treatment plant was installed. This scenario, with its large population, distinct period of high exposure, and accurate data on past exposure, is virtually unprecedented in environmental epidemiology. We conducted a pilot study on early-life arsenic exposure and long-term lung function. We present these preliminary findings because of the magnitude of the effects observed. METHODS: We recruited a convenience sample consisting primarily of nursing school employees in Antofagasta and Arica, a city with low drinking water arsenic. Lung function and respiratory symptoms in 32 adults exposed to >800 µg/l arsenic before age 10 were compared to 65 adults without high early-life exposure. RESULTS: Early-life arsenic exposure was associated with 11.5% lower forced expiratory volume in 1 s (FEV(1)) (P = 0.04), 12.2% lower forced vital capacity (FVC) (P = 0.04), and increased breathlessness (prevalence odds ratio = 5.94, 95% confidence interval 1.36-26.0). Exposure-response relationships between early-life arsenic concentration and adult FEV(1) and FVC were also identified (P trend = 0.03). CONCLUSIONS: Early-life exposure to arsenic in drinking water may have irreversible respiratory effects of a magnitude similar to smoking throughout adulthood. Given the small study size and non-random recruitment methods, further research is needed to confirm these findings.

Arsenic exposure and risk of spontaneous abortion, stillbirth, and infant mortality.

BACKGROUND: Millions of people worldwide are drinking water with elevated arsenic concentrations. Epidemiologic studies, mainly cross-sectional in design, have suggested that arsenic in drinking water may affect pregnancy outcome and infant health. We assessed the association of arsenic exposure with adverse pregnancy outcomes and infant mortality in a prospective cohort study of pregnant women. METHODS: A population-based, prospective cohort study of 2924 pregnant women was carried out during 2002-2004 in Matlab, Bangladesh. Spontaneous abortion was evaluated in relation to urinary arsenic concentrations at gestational week 8. Stillbirth and infant mortality were evaluated in relation to the average of urinary arsenic concentrations measured at gestational weeks 8 and 30. RESULTS: : The odds ratio of spontaneous abortion was 1.4 (95% confidence interval [CI] = 0.96-2.2) among women with urine arsenic concentrations in the fifth quintile (249-1253 µg/L; median = 382 µg/L), compared with women in the first quintile (<33 µg/L). There was no clear evidence of increased rates of stillbirth. The rate of infant mortality increased with increasing arsenic exposure: the hazard ratio was 5.0 (95% CI = 1.4-18) in the fifth quintile of maternal urinary arsenic concentrations (268-2019 µg/L; median = 390 µg/L), compared with the first quintile (<38 µg/L). CONCLUSIONS: We found evidence of increased risk of infant mortality with increasing arsenic exposure during pregnancy, with less evidence of associations with spontaneous abortion or stillbirth risk.

Kidney cancer mortality: fifty-year latency patterns related to arsenic exposure.

BACKGROUND: Arsenic in drinking water is associated with kidney cancer. Beginning in 1958, a region of Chile experienced a rapid onset of high arsenic exposure in drinking water, followed by sharp declines when water treatment plants were installed in 1971. METHODS: For the years 1950-1970, we obtained mortality data from death certificates for an exposed region and an unexposed region in Chile. We obtained computerized mortality data for all of Chile for 1971-2000. RESULTS: Kidney cancer risks for the exposed region compared with the unexposed started to increase about 10 years after high arsenic exposures began in 1958. The peak kidney cancer mortality rate ratio (RR) was 3.4 (95% confidence interval = 2.2-5.1) for men in 1981-1985, with subsequent declines to 1.6 (1.2-2.1) by 1996-2000. Mortality RRs among women were 2.9 (1.8-4.7) in 1981-1985 but remained high longer than for men, increasing further to a RR of 4.4 (3.0-6.4) in 1991-1995. Early-life exposure resulted in an increased RR of 7.1 (3.1-14) for young adults aged 30-39 years, born just before or during the high exposure period. CONCLUSIONS: This study shows a latency pattern of increased mortality from kidney cancer, continuing for at least 25 years after the high exposures began to decline. Early life exposure resulted in markedly higher kidney cancer mortality in young adults.