A population level study on smoking and radon induced adenocarcinoma and small-cell carcinoma among males and females in Canada

Abstract

Objective

To assess if there is a relationship between residential radon exposure and two lung cancer histological types, small-cell carcinoma (diagnosed in people with a smoking history) and adenocarcinoma (the most commonly diagnosed histologic type in people who have never smoked) among males and females in Canada.

Methods

With survey data of long-term radon measurements in residential homes, long-term averaged tobacco consumption rates in the units of cigarettes per day per person and long-term averaged age-standardized lung cancer incidence rates at provincial level, simple linear fitting (ANOVA linear regression) was applied in this study to determine the effect on lung cancer induction by smoking and exposure to indoor radon, and to assess if there is a relationship between residential radon exposure and lung cancer histological types.

Results

Lung cancer incidence rates correlate very well with the tobacco consumption rates (P ​< ​0.05). However, females appear to be more likely than males to develop lung cancer at a given amount of cigarette consumption. For both small-cell carcinoma and adenocarcinoma, a statistically significant correlation between incidence rate and mean radon concentration was observed for females, the correlation was much stronger for adenocarcinoma (P ​= ​0.0057) than small-cell carcinoma (P ​= ​0.0483). However, there was no such correlation for males.

Conclusion

It is possible that female non-smokers are more susceptible to radon-induced lung cancer, and the joint effect of radon exposure and tobacco smoking may be worse in female smokers compared to males, such that higher incidence rate of adenocarcinoma among females compared to males were observed in recent decades, even though females never smoked more than males.