Abstract
The age-adjusted death rates for lung cancer have markedly increased in many countries. Observing by age group, however, the death rates have begun to decrease in the younger population in many countries except Japan. The trends in morbidity incidence rates for lung cancer also showed decline in younger ages, especially among males, in some countries. These facts suggest that the exposure to risk factors of lung cancer has declined in such countries.
The age-adjusted death rates for lung cancer and the increasing rates of those death rates were observed in prefectures in Japan, and it was found that the geographical difference in the incidence of lung cancer was decreasing in Japan.
