Smoking and weight in the 1983 Italian National Health Survey.

The relation between smoking habits and weight was evaluated using data of the 1983 Italian National Health Survey on 72,284 individuals aged 15 years or over, randomly selected within strata of geographical area, size of the place of residence and of the household in order to be representative of the whole Italian population. Female moderate smokers were less frequently overweight or obese, thus confirming previous observations in other populations. However, in contrast with other observations, male current smokers were not lighter than 'never' smokers, and in particular smokers were less frequently underweight. Thus, the relation between smoking status and indicators of body weight was heterogeneous in the two sexes. Further, in both sexes the relationship between amount smoked and obesity was not linear, heavy smokers being more frequently overweight than moderate smokers. In conclusion, although these population-based data confirm that smoking habits are a correlate of weight, the absence of any dose-effect relationship and the inter-sex differences suggest that the relation between smoking and weight in the Italian population is probably partly or largely indirect.