Cigarette smoking and body weight in the Cancer Prevention Study I.

To investigate the generality of the association of heavy cigarette smoking with increased body weight, the relation of number of cigarettes smoked per day to relative body weight was examined in baseline data for 891,589 participants in a prospective study initiated in 1959. Although the relative weight of cigarette smokers was consistently lower than that of never and exsmokers, men and women smoking two or more packs of cigarettes per day were more likely to be categorized as moderately or severely overweight and less likely to be categorized as underweight than those smoking 10-20 cigarettes per day, despite somewhat greater educational attainment by heavier smokers. These analyses offer support for the temporal generality of the relation between heavier cigarette smoking and greater body weight, and suggest that this phenomenon cannot be explained by historic trends in the socioeconomic stratification of smoking prevalence or smoking dose.