Role of smoking and diet in the cross-cultural variation in lung-cancer mortality: The seven countries study

We examined the role of smoking and diet in the cross-cultural variation in lung-cancer mortality, using aggregated data of the Seven Countries Study, a follow-up study comprising 12,763 middle-aged men in 16 cohorts in Europe, the United States and Japan, which started around 1960. Smoking habits were assessed with a standardised questionnaire. Dietary intake was collected in random sub-samples of each cohort by the dietary record method....