Lung Cancer and Radon: Pooled Analysis of Uranium Miners Hired in 1960 or Later.

BACKGROUND: Despite reductions in exposure for workers and the general public, radon remains a leading cause of lung cancer. Prior studies of underground miners depended heavily upon information on deaths among miners employed in the early years of mine operations when exposures were high and tended to be poorly estimated. OBJECTIVES: To strengthen the basis for radiation protection, we report on the follow-up of workers employed in the later periods of mine operations for whom we have more accurate exposure information and for whom exposures tended to be accrued at intensities that are more comparable to contemporary settings. METHODS: We conducted a pooled analysis of cohort studies of lung cancer mortality among 57,873 male uranium miners in Canada, Czech Republic, France, Germany, and the United States, who were first employed in 1960 or later (thereby excluding miners employed during the periods of highest exposure and focusing on miners who tend to have higher quality assessments of radon progeny exposures). We derived estimates of excess relative rate per 100 working level months (ERR/100 WLM) for mortality from lung cancer. RESULTS: The analysis included 1.9 million person-years of observation and 1,217 deaths due to lung cancer. The relative rate of lung cancer increased in a linear fashion with cumulative exposure to radon progeny (ERR/100 WLM=1.33; 95% CI: 0.89, 1.88). The association was modified by attained age, age at exposure, and annual exposure rate; for attained ages <55 y, the ERR/100 WLM was 8.38 (95% CI: 3.30, 18.99) among miners who were exposed at ≥35 years of age and at annual exposure rates of <0.5 working levels. This association decreased with older attained ages, younger ages at exposure, and higher exposure rates. DISCUSSION: Estimates of association between radon progeny exposure and lung cancer mortality among relatively contemporary miners are coherent with estimates used to inform current protection guidelines. https://doi.org/10.1289/EHP10669.

Histopathologic Analysis of Lung Cancer Incidence Associated with Radon Exposure among Ontario Uranium Miners.

Although radon is a well-established contributor to lung cancer mortality among uranium miners, the effects of radon decay products on different histopathologies of lung carcinoma are not well established. Using a retrospective cohort design, this study aims to examine the risks of lung cancer by histological subtypes associated with exposure to radon decay products among the Ontario Uranium Miners cohort. Cases were stratified by histological groups, and associated risks were estimated for cumulative radon exposure after adjustment for attained age and calendar period. Between 1969 and 2005, 1274 incident cases of primary lung cancer were identified. Of these, 1256 diagnoses (99%) contained information on histology. Squamous cell carcinoma was most common (31%), followed by adenocarcinoma (20%), large cells (18%), small cell lung carcinoma (14%), and other or unspecified cell types (17%). Of the histological sub-groups, small cell lung carcinoma had the strongest association with cumulative radon exposure; compared to the reference group (<1 cumulative working level months (WLM)), the highest exposure category (>60 cumulative WLM) had a relative risk (RR) of 2.76 (95% CI: 1.67⁻4.57). Adenocarcinoma had the lowest risk and was not significantly associated with exposure to radon decay products (RR = 1.49, 95% CI: 0.96⁻2.31). An increasing, linear trend in relative risk was noted with increasing cumulative WLM across small cell, squamous cell, and large cell lung carcinomas (Ptrend < 0.05). Similarly, the excess relative risk (ERR) per WLM was highest for small cell lung carcinoma (ERR/WLM = 0.15, p < 0.01), followed by squamous cell carcinoma (ERR/WLM = 0.12, p < 0.01). Non-statistically significant excess risk was observed for adenocarcinoma (ERR/WLM = 0.004, p = 0.07). Our analysis of the Ontario Uranium Miners cohort data shows differences in the magnitude of the risks across four histological subtypes of lung carcinoma; the strongest association was noted for small cell lung carcinoma, followed by squamous cell, large cell, and lastly adenocarcinoma, which showed no significant associations with exposure to radon decay products.

Risk of Lung Cancer Mortality in Nuclear Workers from Internal Exposure to Alpha Particle-emitting Radionuclides.

BACKGROUND: Carcinogenic risks of internal exposures to alpha-emitters (except radon) are poorly understood. Since exposure to alpha particles-particularly through inhalation-occurs in a range of settings, understanding consequent risks is a public health priority. We aimed to quantify dose-response relationships between lung dose from alpha-emitters and lung cancer in nuclear workers. METHODS: We conducted a case-control study, nested within Belgian, French, and UK cohorts of uranium and plutonium workers. Cases were workers who died from lung cancer; one to three controls were matched to each. Lung doses from alpha-emitters were assessed using bioassay data. We estimated excess odds ratio (OR) of lung cancer per gray (Gy) of lung dose. RESULTS: The study comprised 553 cases and 1,333 controls. Median positive total alpha lung dose was 2.42 mGy (mean: 8.13 mGy; maximum: 316 mGy); for plutonium the median was 1.27 mGy and for uranium 2.17 mGy. Excess OR/Gy (90% confidence interval)-adjusted for external radiation, socioeconomic status, and smoking-was 11 (2.6, 24) for total alpha dose, 50 (17, 106) for plutonium, and 5.3 (-1.9, 18) for uranium. CONCLUSIONS: We found strong evidence for associations between low doses from alpha-emitters and lung cancer risk. The excess OR/Gy was greater for plutonium than uranium, though confidence intervals overlap. Risk estimates were similar to those estimated previously in plutonium workers, and in uranium miners exposed to radon and its progeny. Expressed as risk/equivalent dose in sieverts (Sv), our estimates are somewhat larger than but consistent with those for atomic bomb survivors.See video abstract at, http://links.lww.com/EDE/B232.

Status report -- Childhood overweight and obesity in Canada: an integrative assessment. / Rapport d'étape -- Embonpoint et obésité chez les enfants au Canada : une évaluation globale.

INTRODUCTION: Obesity is a complex risk factor for chronic disease that is associated with a number of socioecological determinants. In this status report, we provide an overview of the socioecological framework that is now guiding our ongoing surveillance efforts in the area of childhood overweight and obesity. This framework considers individual risk and protective factors (sociodemographic, lifestyle, psychosocial and early-life) through the lens of the life stage, levels of influence and environments in which these factors play a role. METHODS: Using data from the Canadian Community Health Survey and the Canadian Health Measures Survey, univariate and bivariate analyses were used to report on behavioural, psychosocial, and early life factors associated with excess weight among Canadian children. RESULTS: Estimates of early-life (e.g. breastfeeding), behavioural (e.g. physical activity), and psychosocial factors (e.g. sense of community) are presented as they relate to age group, sex, income adequacy and weight status. CONCLUSION: Building upon our recent reporting on trends in and sociodemographic factors associated with childhood obesity in Canada, this work illustrates the remaining risk and protective factors shown in our surveillance framework. This analysis supports the shift towards a holistic appraisal of determinants related to healthy weights.

INTRODUCTION: L'obésité est un facteur de risque complexe des maladies chroniques associé à un certain nombre de déterminants socioécologiques. Ce rapport d'étape fournit un aperçu du cadre socioécologique qui guide actuellement nos efforts de suivi de l'embonpoint et de l'obésité chez les enfants. Ce cadre intègre différents facteurs de risque et de protection (facteurs sociodémographiques, liés au mode de vie, psychosociaux et en début de vie) et tient compte de l'étape de vie, des niveaux d'influence et de l'environnement au sein desquels ces facteurs jouent un rôle. MÉTHODOLOGIE: Nous avons effectué des analyses univariées et bivariées fondées sur les données de l'Enquête sur la santé dans les collectivités canadiennes et de l'Enquête canadienne sur les mesures de la santé pour rendre compte des facteurs comportementaux, des facteurs psychosociaux et des facteurs en début de vie associés à un surplus de poids chez les enfants canadiens. RÉSULTATS: Les estimations liées aux facteurs en début de vie (p. ex. l'allaitement), aux facteurs comportementaux (p. ex. l'activité physique) et aux facteurs psychosociaux (p. ex. le sentiment d'appartenance à la collectivité) sont présentées en fonction du groupe d'âge, du sexe, de la suffisance du revenu et du poids. CONCLUSION: Cette étude, qui s'appuie sur notre publication récente sur les tendances en matière d'obésité chez les enfants au Canada et les facteurs sociodémographiques qui y sont associés, présente les facteurs de risque et de protection intégrés à notre cadre de surveillance. D'après notre analyse, une évaluation plus globale des déterminants associés au maintien d'un poids santé est nécessaire.