Differences in lung cancer mortality trends from 1986-2012 by radon risk areas in British Columbia, Canada

Residential exposure to radon gas is associated with increased risk of lung cancer, especially in smokers. Most evidence about the health effects of radon has been derived from meta-analyses on global epidemiologic studies, but administrative data can help public health authorities to explore the local impacts. Eighty health units in British Columbia (BC), Canada, were classified as having low, moderate, or high radon risk using more than 3,800 residential measurements. Vital statistics records were used to identify deaths due to lung cancer and to all natural causes. The annual ratio of lung cancer mortality to all natural mortality was plotted for the 1986-2012 study period for each radon classification. Visualizations were stratified by gender and by smoking prevalence. The overall ratio increased throughout the study period in high radon areas and remained stable in low and moderate radon areas. The increase was most pronounced for females, especially when plots were stratified by smoking prevalence. These limited but interesting findings confirm that radon is one risk factor for lung cancer mortality in BC and that its effects differ across gender and smoking strata. The results would be strengthened by replication, and more rigorous methods are required to assess other contributing factors.