[Lung cancer].

Abstract

The number of lung cancer deaths in Japan has been continuously increasing for decades, mainly because of the growing size of the elderly population. In contrast, age-specific lung cancer death rates for those aged under 79 years plateaued recently, reflecting the decreasing smoking rates since 1966. However, the smoking rate for males (54% in 1999) is still extraordinarily high in Japan compared to other developed countries, so it is necessary to further promote anti-smoking activities. It is reported that the relative risk for lung cancer due to cigarette smoking increases 4-5 fold (current smokers versus non-smokers) for males and 2-3 fold for females, and that the population attributable risk is 70% for males and 15-25% for females in Japan, which indicates that cigarette smoking is the most influential risk factor for lung cancer. However, the magnitude of the relative risk and population attributable risk is not as high as those observed in other developed countries. In order to clarify the reasons for this, it is necessary to further accumulate findings from actual epidemiological studies in Japan. In addition to cigarette smoking, occupational exposures, dietary habits (low intake of vegetables and fruits), atmospheric air pollution, environmental tobacco smoke, cooking and heating fuels, indoor radon and previous lung diseases are reported to increase the risk of lung cancer.