Sandra Cortés

Drinking water arsenic in northern Chile: high cancer risks 40 years after exposure cessation

Background: Millions of people worldwide are exposed to arsenic-contaminated water. In the largest city in northern Chile (Antofagasta), more than 250,000 people were exposed to high arsenic drinking water concentrations from 1958 until 1970 when a water treatment plant was installed. Because of its unique geology, limited water sources, and good historical records, lifetime exposure and long-term latency patterns can be assessed in this area with better accuracy than in other arsenic-exposed areas worldwide. Methods: We conducted a population-based case–control study in northern Chile from October 2007 to December 2010 involving 232 bladder and 306 lung cancer cases and 640 age- and gender-matched controls, with detailed information on past exposure and potential confounders, including smoking and occupation. Results: Bladder cancer ORs for quartiles of average arsenic concentrations in water before 1971 (<11, 11–90, 91–335, and >335 μg/L) were 1.00, 1.36 [95% confidence interval (CI), 0.78–2.37], 3.87 (2.25–6.64), and 6.50 (3.69–11.43), respectively. Corresponding lung cancer ORs were 1.00, 1.27 (0.81–1.98), 2.00 (1.24–3.24), and 4.32 (2.60–7.17). Bladder and lung cancer ORs in those highly exposed in Antofagasta during 1958 to 1970 but not thereafter were 6.88 (3.84–12.32) and 4.35 (2.57–7.36), respectively. Conclusions: The lung and bladder cancer risks that we found up to 40 years after high exposures have ended are very high. Impact: Our findings suggest that prevention, treatment, and other mortality reduction efforts in arsenic-exposed countries will be needed for decades after exposure cessation. Cancer Epidemiol Biomarkers Prev; 22(4); 623–30. ©2013 AACR.

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.

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.

High intraspecific variability of Echinococcus granulosus sensu stricto in Chile

Echinococcus granulosus sensu stricto is the major cause of cystic echinococcosis in most human and animal cases in the world and the most widespread species within the E. granulosus sensu lato complex. E. granulosus s.s. remains endemic in South America together with other species of the Echinococcus genus, especially in some areas in Argentina, Brazil, Chile and Peru. Except for a single human case caused by E. canadensis (G6) described in the literature, only E. granulosus s.s. has been found in the Chilean territory. In the current study 1609bp of the cox1 gene from 69 Chilean isolates of E. granulosus s.s. from humans and animals were analysed. In total, 26 cox1 haplotypes were found, including the widespread haplotype EG01 (22 isolates) and also EGp1 (5), EgRUS7 (1), EgAus02 (1) and EgAus03 (2). Twenty-one different haplotype not previously described were identified from 38 Chilean isolates designated EgCL1-EgCL21. Previous work had described low variability of E. granulosus s.s. in South America, based on isolates from Peru. Results obtained in this work challenge the previously described idea of the low diversity of the parasite in South America, and warrant future investigation on the origin and spread of the parasite in the continent after the Spanish arrival.

First meeting "cystic echinococcosis in Chile, update in alternatives for control and diagnostics in animals and humans"

This report summarizes the outcomes of a meeting on cystic echinococcosis (CE) in animals and humans in Chile held in Santiago, Chile, between the 21st and 22nd of January 2016. The meeting participants included representatives of the Departamento de Zoonosis, Ministerio de Salud (Zoonotic Diseases Department, Ministry of Health), representatives of the Secretarias Regionales del Ministerio de Salud (Regional Department of Health, Ministry of Health), Instituto Nacional de Desarrollo Agropecuario (National Institute for the Development of Agriculture and Livestock, INDAP), Instituto de Salud Pública (National Institute for Public Health, ISP) and the Servicio Agrícola y Ganadero (Animal Health Department, SAG), academics from various universities, veterinarians and physicians. Current and future CE control activities were discussed. It was noted that the EG95 vaccine was being implemented for the first time in pilot control programmes, with the vaccine scheduled during 2016 in two different regions in the South of Chile. In relation to use of the vaccine, the need was highlighted for acquiring good quality data, based on CE findings at slaughterhouse, previous to initiation of vaccination so as to enable correct assessment of the efficacy of the vaccine in the following years. The current world’s-best-practice concerning the use of ultrasound as a diagnostic tool for the screening population in highly endemic remote and poor areas was also discussed.

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 (<60 &mgr;g/L), those in the middle (60–623 &mgr;g/L) and upper (>623 &mgr;g/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. HighlightsNorthern Chile is one of the driest places on earth.Historical arsenic water measurements allow for estimation of lifetime exposure.Associations between arsenic and hypertension were identified using these data.Control for body mass index, smoking and other factors had little impact on results.

Study protocol for the Maule Cohort (MAUCO) of chronic diseases, Chile 2014–2024

BackgroundMaule Cohort (MAUCO), a Chilean cohort study, seeks to analyze the natural history of chronic diseases in the agricultural county of Molina (40,000 inhabitants) in the Maule Region, Chile. Molina´s population is of particular interest because in the last few decades it changed from being undernourished to suffering excess caloric intake, and it currently has the highest national rates of cardiovascular diseases, stomach cancer and gallbladder cancer. Between 2009 and 2011 Molina´s poverty rate dropped from 24.1 % to 13.5 % (national average 20.4 %); in this period the county went from insufficient to almost complete basic sanitation. Despite these advances, chemical pollutants in the food and air are increasing. Thus, in Molina risk factors typical of both under-developed and developed countries coexist, generating a unique profile associated with inflammation, oxidative stress and chronic diseases.Methods/DesignMAUCO is the core project of the recently established Advanced Center for Chronic Diseases (ACCDiS), Universidad de Chile & Pontificia Universidad Católica de Chile. In this study, we are enrolling and following 10,000 adults aged 38 to 74 years over 10 years. All eligible Molina residents will be enrolled. Participants were identified through a household census. Consenting individuals answer an epidemiological survey exploring risk factors (psycho-social, pesticides, diet, alcohol, and physical activity), medical history and physical and cognitive conditions; provide fasting blood, urine, and saliva samples; receive an electrocardiogram, abdominal ultrasound and bio-impedance test; and take a hand-grip strength test. These subjects will be re-interviewed after 2, 5 and 7 years. Active surveillance of health events is in place throughout the regional healthcare system. The MAUCO Bio-Bank will store 30 to 50 aliquots per subject using an NIH/NCI biorepository system for secure and anonymous linkage of samples with data.DiscussionMAUCO´s results will help design public health interventions tailored to agricultural populations in Latin America.

Urinary Metal Levels in a Chilean Community 31 Years After the Dumping of Mine Tailings

Background Between 1938 and 1975, the city of Chañaral, located in the north of Chile, received 200 megatons of unregulated mining waste, which created an artificial beach 10 kilometers long and covering an area larger than 4 km2. In 1983, this deposit was classified as a serious case of marine pollution in the Pacific Ocean, according to the Organization for Economic Cooperation and Development. In 1989, dumping ceased due to a judicial order. Until now, the effects of this pollution on the population living around these mine tailings has been unknown. Objective To determine the prevalence of exposure to metals by dust from mine tailings in Chañaral, a city located in the northern mining area of Chile. Methods The level of urinary metals in a representative sample of adults from Chanaral was determined. Results Urinary levels of total arsenic (44.6 μg/L), inorganic arsenic (17.0 μg/L) and nickel (2.8 μg/L) were higher than in other areas of Chile. Levels of copper (17.9 μg/L), mercury (1.6 μg/L) and lead (0.9 μg/L) exceeded international values. Of the total subjects, 67.5%, 30.4%, 29.4%, 16.9%, 13.2 and 9.3% presented with high levels of copper, nickel, total arsenic, inorganic arsenic, mercury and lead, respectively. Conclusion Thirty-one years after suspension of the discharge of mining waste, the local population in this area remains exposed to metals from the mine tailings. Surveillance and remedial actions addressing the Chañaral mine tailings are needed.

Exposición a nitratos en agua y su relación con disfunción de la glándula tiroides: revisión sistemática ¿Existen riesgos para la salud de la población?

BACKGROUND Nitrate exposure may be associated with thyroid gland dysfunction. AIM To review the available evidence about the relationship between nitrates in drinking water and thyroid gland dysfunction. MATERIAL AND METHODS A wide search was performed using Medline, Cochrane, Lilacs, IBECS and Scielo databases using pertinent keywords, finding a total of 66 related studies. After filtering and in depth reviewing, a total of 12 studies were included in this review. RESULTS The main results reveal the importance of this ion for human health, finding evidence both in animals and human beings that suggest pathological changes in the gland as its relationship with the occurrence of subclinical hypothyroidism, and potentially cancer of the thyroid gland. In Chile, nitrate is not considered a critical contaminant so its regular measuring and control is not enforced. CONCLUSIONS In light of the present review we believe that there is evidence to consider nitrate as a critical contaminant whose measurement, registration and correct implementation of valid policies would have a direct benefit for the population of this country. Without this information, it is not possible to quantify the damage to human health, especially in vulnerable groups residing in areas at greatest risk of exposure.

Análisis espacial de la anemia gestacional en el Perú, 2015

Objectives To establish regional prevalences of anemia in pregnant women receiving care at public clinics in Peru in 2015 and identify high-prevalence district conglomerates. Materials and Methods An ecological study was carried out on data from pregnant women with anemia registered on the Nutritional Status Information System (SIEN) who received care in 7703 public clinics in 2015. Regional and district prevalences of gestational anemia were calculated. District conglomerates with a high prevalence of gestational anemia were identified using the Moran Index. Results Information was gathered from 311,521 pregnant women distributed in 1638 districts in Peru. The national prevalence of anemia was 24.2% (95% confidence interval [95% CI]: 24.0-24.3%), the rural prevalence was 30.5%, and the urban prevalence was 22.0%. The regions of Huancavelica (45.5%; 95% CI: 44.2-46.7%), Puno (42.8%; 95% CI: 41.9-43.7%), Pasco (38.5%; 95% CI: 36.9-40.0%), Cusco (36.0%; 95% CI: 35.3-36.8%), and Apurímac (32.0%; 95% CI: 30.8-33.1%) had the highest prevalences of anemia. The local Moran Index identified 202 high-priority districts (hot spots) (12.3% of total; 44 urban and 158 rural) located in Ancash, Apurímac, Arequipa, Ayacucho, Cajamarca, Cusco, Huancavelica, Huánuco, Junín, La Libertad, Lima, Pasco, and Puno containing high-prevalence district conglomerates. Conclusions Gestational anemia in Peru has its highest prevalence rates in rural and southern mountainous areas. The district conglomerates with high prevalence rates of gestational anemia coincide with the areas of high regional prevalence.