592 evidence that ingested arsenic might follow this pattern came from the limited investigations of children in Anto- fagasta, Chile (Borgo n˜o et al. 1977; Zaldivar 1980). More recently, studies have linked arsenic in drinking water to lung function, cough, breathlessness, crepitations, chronic bronchitis, and bronchiectasis (De et al. 2004; Guha Mazumder et al. 2000, 2005; Guo et al. 2007; Milton and Rahman 2002; Parvez et al. 2008; von Ehrenstein et al. 2005). Most data, however, involve adults with recent exposures. The long-term impacts of early-life arsenic exposures are largely unknown. An ecologic study of northern Chile found increased lung cancer, bronchiectasis, and other chronic obstructive pulmonary disease (COPD) mortality several decades after high in utero and early- childhood arsenic exposure (Smith et al. 2006). In this paper, we present a pilot study on adult lung function in relation to estimated early-life exposure in the same region using individual-level data. Materials and methods Study area Northern Chile is among the driest places on Earth. Nearly everyone there obtains water from municipal supplies, which have arsenic measurements dating back to the 1950s. The absence of alternative water sources means that peo- ple’s lifetime arsenic exposures can be estimated simply by knowing in which cities they lived. In Antofagasta (popu- lation 257,976), drinking water arsenic concentrations were about 90 lg/l until 1958, when arsenic-contaminated rivers were tapped to supply the growing population. Drinking water concentrations averaged 870 lg/l until the world’s ﬁrst large arsenic removal plant became operational in May 1970. From then on, concentrations remained below 150 lg/l with few exceptions. Current levels are around 10 lg/l, the World Health Organization guideline (WHO 2004). This unusual exposure scenario created a population of tens of thousands of people exposed to high levels of arsenic in utero or as young children but not as adults. By contrast, the nearby city of Arica (population 193,788) has always had drinking water arsenic levels around 10 lg/l. Other cities in northern Chile had variable arsenic levels, but none approached those of Antofagasta (Ferreccio et al. 2000). Study design and participants In this pilot study, we compared lung function and preva- lence of respiratory symptoms in adults with and without high early-life arsenic exposures. The exposed population comprised long-term residents of Antofagasta, while the 123 Int Arch Occup Environ Health (2011) 84:591–600 unexposed comparison group comprised mostly long-term residents of Arica. A convenience sample was recruited by 2 local nurse-interviewers in each city, who invited employees at the major nursing schools (Universidad Ta- rapaca´ de Arica and Universidad de Antofagasta) through personal communication and ﬂiers posted on campus. Interviews and lung function tests were conducted from August 11–21, 2008, in a classroom on campus for 3 days in each city. In total, we enrolled 97 subjects, primarily administrative staff, custodians, and facility workers. Par- ticipants were 32–65 years old, such that they would have been young children or in utero during the high exposure period in Antofagasta. The study protocol was approved by the institutional review boards of the University of Cali- fornia, Berkeley, and the Pontiﬁcia Universidad Cato´lica de Chile. All subjects gave written informed consent before participating. Interviews Each participant was administered a structured question- naire to assess lifetime residential and occupational history (all jobs or residences occupied C6 months), water source types (municipal tap water, bottled, other), current medi- cations, and medical history. Smoking histories included ages started and quit, years smoked, and average cigarettes smoked per day. Ever smoking regularly was deﬁned as smoking cigarettes at least once per week for C1 year, or 20 packs lifetime. Secondhand smoke was deﬁned as someone smoking regularly in the same room at home or at work. Indoor air pollution was deﬁned as irritating or vis- ible smoke, vapors, gases, or dust regularly in the same room. Subjects were also asked about the types of fuels used at home. Occupational exposure was deﬁned as ever being exposed regularly to vapors, dust, gas, or fumes at a job held for C6 months (Blanc et al. 2005). Standardized questions were adapted to local Spanish from question- naires used by the Latin American Project for the Investi- gation of Obstructive Lung Diseases (PLATINO), the third U.S. National Health and Nutrition Examination Survey (NHANES III), and the second European Community Respiratory Health Survey (ECRHS II). Questions about respiratory symptoms were adapted from the British Medical Research Council (Cotes 1987). Participants were asked, ‘‘Do you often cough when you don’t have a cold, such as in the mornings in winter?’’ Chronic cough was assessed with the follow-up question, ‘‘Do you cough like this for at least 3 months a year?’’ The same questions were asked for phlegm. Subjects were also asked whether they had trouble breathing (1) rarely, (2) often, or (3) always. Finally, participants were asked whether they became breathless when (1) hurrying on level ground or walking up a slight hill, (2) walking with other