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OBJECTIVES: Radon is carcinogenic, but more studies are needed to understand relationships with lung cancer and extrathoracic cancers at low exposures. There are few studies evaluating associations with cancer incidence or assessing the modifying effects of smoking. METHODS: We conducted a case-cohort study with 16 434 underground uranium miners in the Czech Republic with cancer incidence follow-up 1977-1996. Associations between radon exposure and lung cancer, and extrathoracic cancer, were estimated with linear excess relative rate (ERR) models. We examined potential modifying effects of smoking, time since exposure and exposure rate. RESULTS: Under a simple ERR model, assuming a 5-year exposure lag, the estimated ERR of lung cancer per 100 working level months (WLM) was 0.54 (95% CI 0.33 to 0.83) and the estimated ERR of extrathoracic cancer per 100 WLM was 0.07 (95% CI -0.17 to 0.72). Most lung cancer cases were observed among smokers (82%), and the estimated ERR of lung cancer per 100 WLM was larger among smokers (ERR/100 WLM=1.35; 95% CI 0.84 to 2.15) than among never smokers (ERR/100 WLM=0.12; 95% CI -0.05 to 0.49). Among smokers, the estimated ERR of lung cancer per 100 WLM decreased with time since exposure from 3.07 (95% CI -0.04 to 10.32) in the period 5-14 years after exposure to 1.05 (95% CI 0.49 to 1.87) in the period 25+ years after exposure. CONCLUSIONS: We observed positive associations between cumulative radon exposure and lung cancer, consistent with prior studies. We observed a positive association between cumulative radon exposure and extrathoracic cancers, although the estimates were small. There was evidence that the association between radon and lung cancer was modified by smoking in a multiplicative or super-multiplicative fashion.

Background: Per‐ and polyfluoroalkyl substances, or PFAS, are a class of chemicals used in nearly all sectors of industry and many consumer products. Their resistance to degradation, however, means that PFAS are ubiquitous in the environment and bioaccumulate. PFAS exposure has also been linked to a variety of adverse health effects. Occupational PFAS exposure is of particular concern as research on PFAS exposure in worker populations has historically been limited and generally restricted to fluorochemical plant workers involved in PFAS production. Methods: A comprehensive review of peer‐reviewed scientific literature was conducted to investigate which worker populations may experience occupational exposure to PFAS. Serum PFAS levels reported in various occupations were analyzed and compared to serum PFAS levels published on the general public exposed to PFAS‐contaminated drinking water and the study population of the National Health and Nutrition Examination Survey (NHANES). Results: Our analysis indicates that professional ski waxers and firefighters may be exposed to several different PFAS at levels often similar to or higher than levels among fluorochemical plant workers and individuals in communities with PFAS‐contaminated drinking water, and higher than levels in the general public. PFAS serum level data on other occupations were largely absent. Conclusions: Results highlight a need for additional research on occupational PFAS exposures and concomitant environmental exposures in these populations. Research on exposure levels in occupations and industries known or suspected to utilize PFAS is critically needed to foster informed recommendations for exposure mitigation measures to protect workers from adverse health effects of PFAS exposure. [ABSTRACT FROM AUTHOR]