A comparative study of smoking, drinking and dietary habits in population samples in France, Italy, Spain and Switzerland. I. Study design and dietary habits.

Diet, tobacco and alcohol consumption, and occupational histories have been investigated in stratified random samples of the adult population in 6 areas in France (departement of Calvados), Italy (province of Varese and city of Torino), Spain (provinces of Navarra and Zaragoza) and Switzerland (canton of Geneva), to be used as a reference group in a case-control study on cancer of the larynx and hypopharynx. Out of a total of 8,074 sampled subjects, 5,564 could be interviewed. Sampling procedures are described, and reasons for non-response are analysed. Everywhere the intake of the 4 energy providing nutrients (particularly alcohol) was much greater in men than in women. In both sexes, total caloric intake was higher in Calvados and in Italy than elsewhere. There were wide inter-area variations in the consumption of butter + milk products and oils, resulting in a polyunsaturated/saturated fatty acid ratio ranging from 0.27 in Calvados to 0.54-0.65 in Spain. Among nutrients suggested to be involved in cancer aetiology, inter-area differences in daily intake were up to 3-fold for carotene and smaller for vitamin C and fibre. The proportion of lipids, fibres, vitamin C and carotene provided by different foods varied widely between areas, thus suggesting that in etiological cancer studies consideration should be given not only to nutrients but also to foods providing them.