Deadly Radon in Montana?

摘要

Noting a negative correlation between average radon levels and lungcancer mortality in Montana counties, Hart (2011) “questions the notionthat radon is deadly in Montana.” Results from a much larger ecologicalstudy of the correlation between county radon levels and lung cancermortality across the whole United States were published in the 1990s(Cohen 1990, 1995). Like Hart, Cohen found an inverse correlationbetween radon concentrations and lung cancer. Such ecological studiessuffer, however, from lack of individual information on radon exposuresand other lung cancer risk factors, including smoking. Indeed, there iscompelling evidence that the observed negative correlation was a spuriousone due to confounding by smoking. First, the same negative correlationbetween radon and cancer mortality was observed for a variety ofsmoking-related cancers, but not for cancers unaffected by smoking(Puskin 2003). More recently, it has been found that – even using averagecounty radon concentrations as a surrogate for individual radon exposure– the correlation between radon and lung cancer becomes positive,once one controls for individual smoking habits (Turner et al. 2011).