Nuevas estrategias de prevención y control de cáncer de cuello uterino en Chile / New strategies for the prevention and control of cervical cancer in Chile

Resumen: Objetivos: Discutir el cáncer cervicouterino (CC), el virus del papiloma humano (VPH), el programa de control del CC y proponer alternativas para Chile. Material y métodos: Se analiza el programa nacional del CC 1966-2015 y la guía clínica 2015-2020, la prevalencia de VPH en mujeres y en casos de CC; la infección y serología de VPH; la autotoma; la precisión y rentabilidad del tamizaje con VPH contra el Papanicolaou y las opciones de triaje en VPH AR positivas. Resultados: En Chile mueren 600 mujeres (principalmente de bajos recursos) al año por CC. La cobertura del Papanicolaou es < 70%, sensibilidad muy inferior al test de VPH, por lo que el cambio es rentable. Desde 2015 se vacuna contra VPH a niñas menores de 13 años. Conclusiones: Las condiciones técnicas y económicas existen en Chile para lograr una mejoría sustancial del CC: se sugiere el reemplazo del Papanicolaou por el examen de VPH; tamizaje cada cinco años con opción de autotoma; triaje con base en la tipificación de VPH 16/18 o Papanicolaou.

Abstract: Objective: To discuss cervical cancer (CC), Human Papilloma Virus (HPV), CC control program and propose alternatives for Chile. Materials and methods: We analyzed the national program of CC 1966-2015 and the clinical CC guideline 2015-2020; HPV prevalence in women and in cases of CC; HPV infection and serology; the self-vaginal sample; the accuracy and cost-effectiveness of screening with HPV versus Papanicolaou, and triage options among HPV-AR positives. Results: 600 women die of CC each year in Chile, mainly from low resources. Papanicolaou coverage is <70%; Papanicolaou sensitivity is much lower than HPV test. Change from Papanicolaou to HPV test is cost-effective. Since 2015, girls under 13 have been vaccinated against HPV. Conclusions: There are the technical and economic conditions for a substantial improvement of CC in Chile: replacement of the Papanicolaou by HPV; screening every five years, with the option of self-sampling, and triage based on HPV 16/18 or Papanicolaou typing.

High exposure to boron in drinking water and sperm parameters in Chilean young people / Exposición elevada a boro en el agua potable y parámetros de esperma en gente joven chilena

Our aim was to describe sperm parameters in residents from Northern Chile. We evaluated in 101 volunteers (18 and 30 years old) urinary and drinking water Boron levels using Inductively Coupled Plasma Mass Spectrometry; semen parameters were measured with standardized methods. Each individual was categorized in 3 levels of exposure: low (B levels in urine 2.94 mgL-1 or tap water 3.0 mgL-1), medium (urinary B between 2.95-7.4 mgL-1 and B in tap water with 3.0-7.0 mgL-1) and high (urinary B > 7.4 mgL-1 or tap water > 7.0 mgL-1). We found no significant differences among groups by pH, sperm concentration (45.1; 48.2 and 38 million/mL), motility 1th hour (38.1; 40.0 and 45.5 %) and vitality 1th hour (88.6; 88.0 and 76.9 %) respectively. Abnormal morphology was significant different (83.3; 90 and 83 %). Young men exposed to B in drinking water present sperm variations associated with the level of exposure. Most of these changes are positive at intermediate levels of B. For the highest exposures were observed negative changes in sperm morphology, concentration, motility and vitality, all relevant parameters of fertility. Beneficial effect is observed at medium exposure, like a "U curve".

El objetivo de este trabajo fue describir los parámetros espermáticos en residentes del norte de Chile. Se evaluaron en 101 voluntarios (18 y 30 años), los niveles urinarios y de agua potable de boro, usando "Inductively Coupled Plasma Mass Spectrometry". Los parámetros del semen se midieron con métodos estandarizados. Cada individuo se clasificó en 3 niveles de exposición: bajo (niveles B en la orina 2,94 mgL-1 o agua potable 3,0 mgL-1), medio (B urinario entre 2,95-7,4 mgL-1 y B en agua de beber con 3,0- 7,0 mgL-1) y alto (B urinario >7,4 mgL-1 o agua potable > 7,0 mgL-1). No se encontraron diferencias significativas entre los grupos por pH, concentración de espermatozoides (45,1; 48,2 y 38 millones/mL), motilidad a 1 hora (38,1; 40,0 y 45,5%) y vitalidad 1 hora (88,6; 88,0 y 76,9%) respectivamente. La morfología anormal fue significativamente diferente (83,3; 90 y 83%). Los hombres jóvenes expuestos a B en el agua potable presentan variaciones espermáticas asociadas con el nivel de exposición. La mayoría de estos cambios son positivos en niveles intermedios de B. Para las exposiciones más altas se observaron cambios negativos en la morfología, concentración, motilidad y vitalidad del esperma, parámetros relevantes de la fertilidad. Un efecto beneficioso se observa en la exposición media, como una "curva U".

Examen de detección de virus papiloma humano en el tamizaje de cáncer cervicouterino en un Servicio de Salud de Santiago, Chile / Human papillomavirus testing in cervical cancer screening at a public health service of Santiago, Chile

Background: Molecular techniques for human papillomavirus (HPV) detection have a good performance as screening tests and could be included in cervical cancer early detection programs. We conducted a population-based trial comparing HPV detection and Papanicolaou as primary screening tests, in a public health service in Santiago, Chile. Aim: To describe the experience of implementing this new molecular test and present the main results of the study. Material and Methods: Women aged 25 to 64 enrolled in three public health centers were invited to participate. In all women, samples were collected for Papanicolaou and HPV DNA testing, and naked-eye visual inspection of the cervix with acetic acid was performed. Women with any positive screening test were referred to the local area hospital for diagnostic confirmation with colposcopy and biopsy of suspicious lesions. Results: Screening results were obtained for 8265 women, of whom 931 (11.3%) were positive to any test. The prevalence of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) was 1.1%; nine women had invasive cervical cancer. Sensitivities for the detection of CIN2+ were 22.1% (95% confidence interval (CI) 16.4-29.2) for Papanicolaou and 92.7% (95% CI 84.4-96.8) for HPV testing; specificities were 98.9% (95% CI 98.7-99.0) and 92.0% (95% CI 91.4-92.6) respectively. Conclusion: This experience showed that the implementation of a molecular test for cervical cancer screening is not a major challenge in Chile: it was well accepted by both the health team and the participants, and it may improve the effectiveness of the screening program.

A snapshot of cancer in Chile: analytical frameworks for developing a cancer policy

INTRODUCTION: The South American country Chile now boasts a life expectancy of over 80 years. As a consequence, Chile now faces the increasing social and economic burden of cancer and must implement political policy to deliver equitable cancer care. Hindering the development of a national cancer policy is the lack of comprehensive analysis of cancer infrastructure and economic impact. OBJECTIVES: Evaluate existing cancer policy, the extent of national investigation and the socio-economic impact of cancer to deliver guidelines for the framing of an equitable national cancer policy. METHODS: Burden, research and care-policy systems were assessed by triangulating objective system metrics -epidemiological, economic, etc. - with political and policy analysis. Analysis of the literature and governmental databases was performed. The oncology community was interviewed and surveyed. RESULTS: Chile utilizes 1% of its gross domestic product on cancer care and treatment. We estimate that the economic impact as measured in Disability Adjusted Life Years to be US$ 3.5 billion. Persistent inequalities still occur in cancer distribution and treatment. A high quality cancer research community is expanding, however, insufficient funding is directed towards disproportionally prevalent stomach, lung and gallbladder cancers. CONCLUSIONS: Chile has a rapidly ageing population wherein 40% smoke, 67% are overweight and 18% abuse alcohol, and thus the corresponding burden of cancer will have a negative impact on an affordable health care system. We conclude that the Chilean government must develop a national cancer strategy, which the authors outline herein and believe is essential to permit equitable cancer care for the country.

HPV vaginal self-sampling among women non-adherent to Papanicolaou screening in Chile / Autotoma vaginal para detección de virus del papiloma humano en mujeres no adherentes a tamizaje con Papanicolaou en Chile

OBJECTIVE: To evaluate acceptance, preference and compliance with referral of vaginal self-sampling for the detection of Human papillomavirus (HPV) among women non-adherent to Papanicolaou (Pap) screening in Santiago, Chile. MATERIALS AND METHODS: Using multistage sampling we identified women aged 30-64 years who reported not receiving a Pap test in the previous three years and offered them Pap testing at the health center or vaginal self-sampling for HPV testing at home. Self-collected samples were analyzed with hybrid capture. All HPV+ women were referred for colposcopy, biopsy and treatment when needed. RESULTS: 1 254 eligible women were contacted; 86.5% performed self-sampling and 8.1% refused; 124 women were HPV+ (11.4%: 95%CI 9.6-13.5) of whom 85.5% attended colposcopy; 12 had CIN2+ (1.1%: 95 %CI 0.5-1.7). CONCLUSION: HPV vaginal self-sampling can be easily implemented in Chile and could improve coverage, successfully reaching women who drop out of the screening program.

OBJETIVO: Evaluar la aceptación, preferencia y adherencia a seguimiento de la autotoma vaginal para detección del virus del papiloma humano (VPH) en mujeres inasistentes a Papanicolaou (Pap) en Santiago, Chile. MATERIAL Y MÉTODOS: Mediante un muestreo polietápico se identificaron mujeres entre 30 y 64 años inasistentes a Pap por < 3 años, invitándolas a realizarse un Pap en su centro de salud o una autotoma vaginal a domicilio. Las muestras fueron analizadas con captura de híbridos. Las mujeres VPH+ fueron referidas a colposcopía, biopsia y tratamiento en caso necesario. RESULTADOS: 1 254 mujeres elegibles fueron contactadas; 86.5% aceptó la autotoma vaginal y 8.1% la rechazó; 124 mujeres resultaron VPH+ (11.4%: IC95% 9.6-13.5) de las que 85.5% asistió a colposcopía; 12 tenían CIN2+ (1.1%: IC95% 0.5-1.7). CONCLUSIÓN: La autotoma vaginal para detección de VPH es implementable en Chile y su utilización podría mejorar la cobertura del programa rescatando a mujeres inasistentes.

El control de la fiebre tifoidea y una reflexión sobre sus efectos a largo plazo en Chile / Typhid fever control and a deliberation about its long term effects in Chile

El texto que presento es un relato, algunas pinceladas gruesas con material de mi memoria, sobre cómo se controló la hiperendemia de tifoidea; presento algunas tasas de apoyo para una reflexión sobre los efectos a largo plazo de la hiperendemia de 1976-1986. Argumento que las actuales altas tasas de cáncer de vesícula biliar serían en parte un resultado de las altas tasas de portadores crónicos de Salmonella typhi.

The text I present is a story, some broad brush strokes drawn from material in my memory, regarding how typhoid hyperendemia was controlled; I present some rates to support a reflection on the long-term effects of the 1976-1986 typhoid hyperendemia. I argue that current high rates of gallbladder cancer may partly be the late effect of high chronic Salmonella typhi carriage.

Análisis de las variables del espermiograma en jóvenes sanos en Arica-Chile / Spermograms of healthy young subjects living in Arica, Chile

Background: Semen analysis is one of the parameters used to predict male fertility. Semen can be altered by environmental pollutants; therefore it could be used as a biological marker of exposure in contaminated areas. Aim: To analyze the spermogram values in a sample of healthy young males, residing in Arica, Chile. Material and methods: One hundred and two healthy university students volunteers aged 18 to 30 years answered a questionnaire about fertility, habits and andrologic diseases and provided a semen sample. Within three hours after ejaculation, semen volume, pH, sperm concentration, motility and morphology were analyzed. Results: Six percent of volunteers had offspring, 1 percent declared to be infertile, 32 percent smoked and 78 percent con-sumed alcohol. Semen pH was 7.6 ± 0.5, volume, 2.9 ± 1.6 ml, sperm concentration, 62.8 ± 62.3 x 10(6)/ml, normal morphology, 15.0 ± 7.9 percent, overall motility, 42.2 ± 23.2 percent and grade A motility, 19.2 ± 18.6 percent. The percentage of subjects that had normal semen values was 82 percent for total sperm count, 76 percent for sperm concentration, 72 percent for volume, 64 percent for vitality, 63 percent for pH, 57 percent for morphology, 38 percent for overall motility and 26 percent for grade A motility. Conclusions: This sample of healthy young males had a normal sperm count in comparison with international reports. However it is necessary to characterize the spermogram in uncontaminated areas of Chile to ensure that our results are within the expected values for the country.

Nuevos paradigmas y desafíos en la prevención y control del cáncer de cuello uterino en América Latina / New paradigms and challenges in cervical cancer prevention and control in Latin America

El cáncer de cuello uterino sigue siendo un problema de salud pública en Latinoamérica. El uso de la citología para la detección de lesiones pre-cancerosas no ha tenido mayor impacto en las tasas de incidencia y mortalidad, que aún se mantienen altas en la región. La disponibilidad de nuevas técnicas de tamizaje para la detección de lesiones pre-cancerosas y de vacunas altamente eficaces que previenen casi todas las lesiones relacionadas con VPH-16 y VPH-18 en mujeres no expuestas previamente al virus representan una gran oportunidad para la prevención del cáncer de cuello uterino en la región. En este manuscrito resumimos la evidencia científica y la experiencia de la región en i) el uso de pruebas de VPH y de la inspección visual después del ácido acético (IVAA) en tamizaje primario, y ii) la implementación de programas de vacunación en adolescentes. Finalmente enumeramos una serie de recomendaciones adecuadas para distintos escenarios. La factibilidad de implementar un programa nacional de prevención de cáncer de cuello uterino exitoso y sostenible en países latinoamericanos dependerá de las prioridades de salud, la infraestructura y personal de salud disponible, determinadas luego de un riguroso análisis situacional local.

Cervical cancer continues to be a significant health problem in Latin America. The use of conventional cytology to detect precancerous cervical lesions has had almost no major impact on reducing cervical cancer incidence and mortality rates, which are still high in the region. The availability of new screening tools to detect precancerous lesions provide great opportunities for cervical cancer prevention in the region, as do highly efficacious HPV vaccines able to prevent nearly all lesions associated with HPV-16 and -18 when applied before viral exposure. This paper summarizes the scientific evidence and regional experiences related to: i) the use of HPV testing and visual inspection after the application of acetic acid (VIA) in primary screening and ii) the implementation of adolescent HPV vaccination programs. Finally, we outline a number of recommendations for different resource settings. The feasibility of implementing successful and sustainable national cervical cancer prevention programs in Latin American countries in the region will depend on health priorities and the availability of infrastructure and health personnel-as determined by rigorous local situational analysis.

Letalidad del cáncer de vesícula biliar es independiente del lugar de atención o características sociodemográficas: Chile 2002-2005 / Mortality due to gallbladder cancer: Retrospective analysis in three Chilean hospitals

Background: Chile has the highest gallbladder cancer (GBC) death rate world-wide, affecting mainly Southern areas of the country. Aim: To compare the survival of GBC patients treated in hospitals located in areas with low and high risk for GBC. Material and Methods: Medical records of all patients with GBC admitted to one public hospital located in southern Chile, a public hospital and a private clinic, both located in Metropolitan Santiago, were reviewed. Cases were analyzed by age, sex, stage at diagnosis, ethnicity, socioeconomic status (SES) and rural residence. Survival was calculated using Kaplan Meier method. Results: A total of 598 cases (469 women), were analyzed. No differences in age or sex among hospitals were detected. At the moment of diagnosis, 75, 50 and 44 percent of cases from the hospital in southern Chile, the public hospital in Santiago and the private clinic in Santiago, were in stage IV, respectively. Five years survival was lower in the public hospital in southern Chile than in the public hospital in Santiago (10.7 and 14.4 percent respectively, p < 0.05) but not statistically different from the figure at the private clinic in Santiago (13.0 percent). However, when adjusting for stage at the moment of diagnosis, no difference in survival between the three hospitals, was found. The median days of survival were 1,559, 188, 70 and 69 for stages I, II, III and IV respectively. Conclusions: GBC mortality is high. The stage at the moment of diagnosis is only significant predictor of survival.

Prevalencia de síndrome metabólico en población adulta Chilena: Datos de la Encuesta Nacional de Salud 2003 / Prevalence of Metabolic Syndrome among Chilean adults

Background: There are several diagnostic criteria for Metabolic Syndrome (MS) defnition. Aim: To study their application in the Chilean general adult population. Material and Methods: We analyzed data from a random sub sample of 1.833 adults aged 17 years and older surveyed during the First Chilean National Health Survey conducted in 2003. The prevalence of MS was estimated using the update Adult Treatment Panel III (ATP III) of the National Cholesterol Education Program (NCEP) and the International Diabetes Federation (IDF 2005) criteria. The distribution of MS was analyzed according to age, gender, educational level, geographic area, obesity and sedentary lifestyle. Results: The overall prevalence of MS was 31.6 percent (95 percent CI 28.5-34.9) and 36.8 percent (95 percent CI 33.5-40.3), according to update ATPIII-NCEP and IDF criteria respectively. Both criteria had a 90 percent concordance. Demographic and socioeconomic distribution was similar for both criteria. The prevalence of high blood pressure, high fasting glucose, and low HDL cholesterol (MS components) were: 46, 22 and 53 percent respectively. The prevalence of abnormal waist circumference was 30 and 59 percent according to update ATPIII-NCEP and IDF criteria, respectively. Using update ATPIII-NCEP criteria, the gender, age and educational level adjusted odds ratio (OR) for having MS was 9.59 (95 percent IC 6.8- 13.6) for obese subjects compared with normal weight subjects and 2.14 (95 percent IC 1.3-3.7) for sedentary subjects compared with non sedentary. Conclusions: There was a 90 percent agreement between update ATPIII-NCEP and IDF criteria for the diagnosis of MS. The overall prevalence of MS in this population was 32 percent usuing update ATPIII-NCEP criteria, with higher prevalence among obese and sedentary subjects.

Factores de riesgo de alteraciones citológicas del cuello uterino en mujeres chilenas: Un estudio de casos y controles / Risk factors associated with abnormal cervical cytology among Chilean women: A case control study

Background: Cervical cancer is the third cause of cancer death among Chilean women, affecting mainly women from low socioeconomic status. Aim: To determine main risk factors (RF) including human papilomavirus (HPV) types associated with abnormal cervical cytology (Atypical Squamous Cells of Undetermined Significance or ASCUS) among Chilean women from low socioeconomic status in Santiago, Chile. Material and Methods: A random population based sample of616 women from La Pintana (a low-income district in Santiago) participated in 2001 in a HPV prevalence study and were re-evaluated in 2006 through a risk factors questionnaire, Papanicolaou test and DNA detection for HPV. The Papanicolaou test was analyzed in Santiago and HPV analysis (PCR_GP5+/GP6+) was conducted in Vrije University, Amsterdam. Cases included 42 women with cervical lesions and controls included 574 women with normal cytology during the period 2001-2006. Logistic regression with uni and multivariate analysis was performed to identify RF for cervical lesions. Results: During the study period, there was a significant increase in the proportion of single women, from 8.3 to 14.8 percent (p < 0.05), of women with 3 or more sexual partners from 8.9 to 13.3 and of women high risk HPV, from 9.1 to 14.3 percent. The proportion of abnormal Papanicolaou tests remained stable (3.08 and 3.9 percent > ASCUS). High risk HPV was the most significant factor associated with cervical lesions (odds ratio (OR) = 9.695 percent> confidence intervals (CI) = 4.4-21.1) followed by oral contraceptive use (OR = 2.58 95 percent> CI= 1.2-5.7). Among women infected by high risk HPV, the use of oral contraceptives was a risk factor while compliance with screening was protective for cervical lesions. Conclusions: From 2001 to 2006, there was an increase in the proportion of women with high-risk HPV infections.

Factores predictores de inicio y cesación de tabaquismo en una cohorte de mujeres chilenas con 5, 5 años de seguimiento / Predictive factors for smoking initiation and quitting among a cohort of Chilean women followed for 5.5 years

Background: Chilean women have one of the highest smoking prevalence in the world. Aim To estimate the main factors associated with smoking initiation and quitting among a cohort of adult women living in a low socioeconomic status area of Santiago, Chile. Material and methods: A random population-based sample of 1,100 women, 18 years and older, were selected from a community located in the South East area of Santiago. Sociodemographic, as well as smoking, beliefs, behaviors, stages of change and nicotine addiction level were recorded during a personal interview. After an average follow-up period of 5.5years, women were re-evaluated. Results: Seventy-three percent of women completed the study. At baseline, 39 percent of women were smokers. At the end of the study, there was an absolute smoking rate reduction of 7.1 percent (p <0.001). The main variables associated with smoking initiation were younger age (Odds ratio (OR): 1.08, 95 percent confidence intervals (CI): 1.05-1.12), higher education level (OR: 1.2, 95 percent CI: 1.07-1.35), and having fewer children (OR: 1.3 95 percent CI: 1.01-1.66). Factors related with quitting were younger age of onset (OR: 1.06 95 percent CI: 1.02-1.1), higher level of nicotine dependence (OR: 4.22, 95 percent CI: 1.74-10.27), and higher perception of smoking addiction (OR: 4.34, 95 percent CI: 2-9.09). Stage of change was associated with smoking cessation but its effect was diluted after adjusting for the level of nicotine addiction. Conclusions: Sociodemographic and family factors were the main variables related with initiation, whereas age of onset, belief of addiction, and nicotine dependence were the main factors related with cessation. Women with a high motivation for quitting should be evaluated for nicotine addiction level to define the best strategy for intervention.

Assessing participation of women in a cervical cancer screening program in Peru / Análisis de la participación de las mujeres en un programa de tamizaje de cáncer cervicouterino en Perú

OBJECTIVE: To assess systemic and individual factors influencing participation of women in a screening program for cervical cancer. METHODS: In November 2000, a new cervical cancer screening program was introduced in the Region of San Martin, Peru. A total of 107 683 women, ages 25-49, were eligible for screening. This report covers the initial period from program inception through 31 October 2003. We used data from the program information system to identify systemic factors and individual characteristics influencing women's participation. We conducted a three-step analysis: we assessed systemic factors at the level of micronetworks or group of health centers, we estimated the odds of being a new user (never screened or not screened in the past 5 years) according to sociodemographic characteristics, and we assessed how women learned about the availability of screening services while controlling for influential factors identified in previous analyses. RESULTS: During the 3-year period, 36 759 eligible women attended screening services, for a participation rate of 32.3 percent. While attendance varied by area and time period, the program attracted 12 208 new users. Health care micronetworks with available static screening services had higher participation. New users were more likely than regular users to have less education and to report low use of family-planning services. All other factors being equal, they were also more likely than regular users to hear about screening services from a health care provider. CONCLUSION: In this setting, the presence of and contact with health services played a role in increasing the participation in screening of women not previously screened or not screened in the past 5 years.

OBJETIVOS: Evaluar los factores sistémicos e individuales que influyen en la participación de las mujeres en un programa de tamizaje de cáncer cervicouterino. MÉTODOS: En noviembre de 2000 se implementó un nuevo programa de tamizaje de cáncer cervicouterino en la región de San Martín, Perú. En total, 107 683 mujeres de 25 a 49 años eran elegibles para el tamizaje. Este informe cubre el período inicial desde el establecimiento del programa hasta el 31 de octubre de 2003. Se utilizaron los datos del sistema de información del programa para identificar los factores sistémicos y las características individuales que influían en la participación de las mujeres. Se realizó un análisis en tres etapas: se evaluaron los factores sistémicos a nivel de las microrredes o grupos de centros de salud, se estimaron las probabilidades de ser una nueva usuaria (nunca tamizada o no tamizada en los últimos 5 años) según las características sociodemográficas y se evaluó la vía por la que las mujeres habían conocido de la disponibilidad de los servicios de tamizaje, controlado por factores de influencia identificados en análisis previos. RESULTADOS: En el período de tres años, 36 759 mujeres elegibles recibieron este servicio, para una tasa de participación de 32,3 por ciento. Aunque la asistencia varió según la zona y el momento, el programa atrajo a 12 208 nuevas usuarias. Las microrredes sanitarias con servicios de tamizaje estáticos tuvieron una mayor participación. Las nuevas usuarias tenían menor nivel educacional y utilizaban menos los servicios de planificación familiar que las mujeres que se habían realizado la prueba con regularidad. Sin diferencias en el resto de los factores, las nuevas usuarias habían oído sobre los servicios de tamizaje más frecuentemente de los trabajadores sanitarios que las usuarias habituales. CONCLUSIONES: En este escenario, la presencia de servicios de salud y el contacto con ellos influyeron en el aumento de la participación...

Arsenic exposure and its impact on health in Chile.

The problem of arsenic in Chile was reviewed. In Chile, the population is exposed to arsenic naturally via drinking-water and by air pollution resulted from mining activities. The sources of arsenic were identified to estimate the exposure of population to arsenic through air, water, and food. Health effects, particularly early effects, observed in children and adults, such as vascular diseases (premature cardiac infarct), respiratory illnesses (bronchiectasis), and skin lesions have been described. Chronic effects, such as lung and bladder cancers, were reported 20 years after peak exposure and persisted 27 years after mitigation measures for removing arsenic from drinking surface water were initiated. Although the effects of arsenic are similar in different ethnic and cultural groups (e.g. Japanese, Chinese, Indian, Bangladeshi, American, and Taiwanese), variations could be explained by age at exposure, the dose received, smoking, and nutrition. Since health effects were observed at arsenic levels of 50 microg/L in drinking-water, it is advised that Chile follows the World Health Organization's recommendation of 10 microg/L. The Chilean experience in removal of arsenic suggests that it is feasible to reach this level using the conventional coagulation process.

Colección de estudios de epidemiología ambiental / Collection of environmental epidemiology studies

En el año 2004, el Departamento de Salud Pública de la Pontificia Universidad Católica desarrolló junto con el SESMA un programa de capacitación en Epidemiología Ambiental en este servicio. El curso se basó en el análisis epidemiológico de los problemas que cada profesional tiene a su cargo: agua, residuos, alimentos, emisiones atmosféricas, zoonosis y salud ocupacional. Se entregaron elementos básicos de bioestadística, epidemiología, relación entre la exposición a contaminantes y efectos en salud.

Lung cancer and arsenic exposure in drinking water: a case-control study in northern Chile

En algunas ciudades de Chile, entre 1950 y 1970, los niveles de arsénico (As) en el agua potable alcanzaron los 800 µg/l, estando hoy en 40µg/l; para evaluar el rol de esta exposición, se llevó a cabo este estudio de casos de cáncer de pulmón y controles en las Regiones I, II y III. Entre 1994 y 1996, se ingresaron casos de cáncer de pulmón y dos controles hospitalarios: un control, un paciente con cáncer y el otro, un paciente sin cáncer, ambos diagnósticos no relacionados con arsénico. Los controles fueron pareados grupalmente por edad y sexo con los casos. A cada sujeto, se le aplicó una encuesta estandarizada sobre residencia, empleo y salud. La información sobre niveles de As en el agua provino de registros de las compañías de agua. Se ingresaron 151 casos de cáncer pulmonar y 419 controles (167 con cáncer y 242 sin cáncer). La mediana de As en el agua potable a lo largo de la vida fue significativamente mayor entre los casos, con una clara relación dosis-respuesta entre el promedio de As y el riesgo, con OR (95 por cento IC) de 1, 1,7 (0,5-5,1), 3,9 (1,2-13,4), 5,5 (2,2-13,5), y 9,0 (3,6-22) para los estratos 1 al 5, respectivamente. Provee nueva evidencia sobre el rol causal del As en el agua potable en cánceres internos y sobre la forma de la relación entre exposición y riesgo de cáncer.