A CASE-CONTROL STUDY OF LUNG-CANCER MORTALITY IN 6 GILA BASIN, ARIZONA SMELTER TOWNS

To investigate factors related to lung cancer mortality in six Arizona copper smelter towns, we identified 185 lung cancer cases and two mat ched controls per case from decedent residents during 1979-1990. Detai led information on lifetime residential, occupational, and smoking his tory was obtained by structured telephone interviews with knowledgeabl e informants. Interviews were completed for 82% of 183 eligible cases and 88% of the targeted number (366) of controls. Estimated historical environmental exposures to smelter emissions, based on atmospheric di ffusion modeling of measured SO2 concentrations, were linked with resi dential histories to derive individual profiles of residential exposur e. Occupational histories were characterized by potential exposure to smelter emissions, asbestos, and ionizing radiation. Conditional logis tic regression was used to compare study factors in cases and controls with adjustment for potential confounding factors: gender, Hispanic e thnicity, and smoking. In overall and gender-specific analyses, no sta tistically significant associations were observed between lung cancer risk and any of the measures of residential exposure to smelter emissi ons considered (town of residence at time of death, highest level of e xposure, and duration or cumulative exposure above background levels), or any of the estimated occupational exposures (definite or potential asbestos, potential ionizing radiation, definite or potential smelter ). Among male residents of some, but not all, towns, there was some ev idence of a positive association between lung cancer risk and reported copper smelter-related employment (reported as definite), with the hi ghest risk observed for Miami, Arizona. This study provided little evi dence of a positive association between lung cancer mortality and resi dential exposure to smelter emissions. Specific factors associated wit h the apparent heterogeneity in lung cancer risk across study towns ca nnot be identified in this community-based study. (C) 1997 Academic Pr ess.