Case-Control Study of Lung Cancer Risk From Residential Radon Exposure in Worcester County, Massachusetts

Abstract

A study of lung cancer risk from residential radon exposure and its radioactive progeny was performed with 200 cases (58% male, 42% female) and 397 controls matched on age and sex, all from the same health maintenance organization. Emphasis was placed on accurate and extensive year-long dosimetry with etch-track detectors in conjunction with careful questioning about historic patterns of in-home mobility. Conditional logistic regression was used to model the outcome of cancer on radon exposure, while controlling for years of residency, smoking, education, income, and years of job exposure to known or potential carcinogens. Smoking was accounted for by nine categories: never smokers, four categories of current smokers, and four categories of former smokers. Radon exposure was divided into six categories (model 1) with break points at 25, 50, 75, 150, and 250 Bq m, the lowest being the reference. Surprisingly, the adjusted odds ratios (AORs) were, in order, 1.00, 0.53, 0.31, 0.47, 0.22, and 2.50 with the third category significantly below 1.0 (p < 0.05), and the second, fourth, and fifth categories approaching statistical significance (p < 0.1). An alternate analysis (model 2) using natural cubic splines allowed calculating AORs as a continuous function of radon exposure. That analysis produces AORs that are substantially less than 1.0 with borderline statistical significance (0.048 < or = p < or = 0.05) between approximately 85 and 123 Bq m. College-educated subjects in comparison to high-school dropouts have a significant reduction in cancer risk after controlling for smoking, years of residency, and job exposures with AOR = 0.30 (95% CI: 0.13, 0.69), p = 0.005 (model 1).

Human Lung Cancer Risks from Radon – Part III - Evidence of Influence of Combined Bystander and Adaptive Response Effects on Radon Case-Control Studies - A Microdose Analysis

“…This is supportive of the non-linear premises of Morgan (2006). Based on these premises, in this Part III, we examine the odds ratio data for these 21 pooled studies, the very recent Massachusetts study of Thompson et al (2008) and the China study of Blot et al (1990) for non-linear lung cancer risks as expected from the results of Parts I and II.…”

Residential Radon and Lung Cancer Risk: An Updated Meta-analysis of Case-control Studies

“…Among them, most were excluded after abstract because they were occupational studies on miners, no case control studies, no relevant exposure or endpoint, and reviews. After assessing the full-text of the 38 relevant articles, we identified 22 eligible studies for meta-analysis (Blot et al, 1990;Schoenberg et al, 1990;Pershagen et al,1992Pershagen et al, , 1994Alavanja et al, 1994Alavanja et al, , 1999Létourneau et al, 1994;Auvinen et al, 1996;Ruosteenoja et al, 1996;Darby et al, 1998;Field et al, 2000;Sobue et al, 2000;Lagarde et al, 2001;Pisa et al, 2001;Barros-Dios et al, 2002;Wang et al, 2002;Baysson et al, 2004;Bochicchio et al, 2005;Wichmann et al, 2005;Sandler et al, 2006;Thompson et al, 2008;Wilcox et al, 2008). Seven studies were excluded for previous mete-analysis (Lubin and Boice, 1997;Pavia et al, 2003) and combined analysis in Europe, North America or China Darby et al, 2005;Krewski et al, 2005;Wang et al, 2005;Darby et al, 2006).…”

“…The number of control ranged from 35 to 4232, with a sum of 21102. Of the included studies, the majority was populationbase control, whereas three were hospital-based control (Baysson et al, 2004;Bochicchio et al, 2005;Thompson et al, 2008) and one combined population and hospital subjects as control (Darby et al, 1998). Half studies ascertained lung cancers from national/local cancer registries and the other half from hospitals.…”

“…All of the studies adjusted for age and smoking. Sex was adjusted in the studies with subjects containing both genders except Thompson (2008) study. For radon dosimetry, 17 studies placed two detectors in the home (bedroom and living room).…”

“…Five studies (Pershagen et al, 1992;Létourneau et Thompson et al, 2008;) were not eligible for the dose-response analysis because they did not provide the required data (eg, the number of cases in each category). The dose-response analysis of the remaining 17 studies showed that the risk of lung cancer increased significantly, on average, by 7% for every 100 Bq/m 3 increment in residential radon exposure (OR: 1.07; 95% CI: 1.04-1.10; P for trend<0.001), and little evidence of heterogeneity was found (P = 0.55).…”