Direct adjustment for confounding by smoking reduces radiation-related cancer risk estimates of mortality among male nuclear workers in Japan, 1999 –2010
A causal relationship between protracted exposure to low-dose rate radiation and health effects
remains unclear despite extensive international studies of nuclear workers. One potential reason is
that radiation epidemiological studies that adjust for tobacco smoking, which heavily influences
mortality, have been limited. In the present study, we examined radiation-related cancer risk by
directly assessing the possible confounding effect of smoking, using data from two questionnaire
surveys performed among Japanese nuclear workers in 1997 and 2003. Mortality follow-up was carried
out for 71 733 male respondents for an average of 8.2 years during the observation period of
1999 –2010. The mean cumulative dose was 25.5 mSv at the end of the follow-up period. Estimates of
excess relative risk per Sv (ERRs/Sv) were obtained by Poisson regression. By adjusting for smoking
directly on the basis of a linear dose-response model, we quantified the confounding effects of
smoking on radiation...
Source: Journal of Radiological Protection - Category: Physics Authors: Shin ’ichi Kudo, Jun’ichi Ishida, Keiko Yoshimoto, Shoichi Mizuno, Sumio Ohshima, Hiroshige Furuta and Fumiyoshi Kasagi Source Type: research