Nondaily smoking: a population-based, longitudinal study of stability and predictors.

backgroundNondaily smoking appears to have remained stable in Western countries in recent years, alongside a steep decline in daily smoking. Nondaily smoking increases the risk of several diseases and premature mortality, but our knowledge about nondaily smoking is limited. The present study was designed to examine the stability of nondaily smoking during young adulthood, and to identify adolescent factors predictive of nondaily smoking compared with nonsmoking and non-nicotine-dependent and nicotine-dependent daily smoking.

methodsA population-based sample (n = 942) of Norwegians was followed up by surveys for 13 years, from adolescence to young adulthood. Information about smoking patterns, nicotine dependence, school achievement, parents' and peers' smoking, and parental monitoring was collected. Data on parental and participants' education were obtained from a national register.

resultsOf all nondaily smokers at age 21 years, 26% were still nondaily smokers at 27 years, while 17% had become daily smokers and 57% had quit. Bivariate analyses revealed that young adult nondaily smokers did not differ from nonsmokers on any of the included variables, while a number of differences in parental, peers' and individual characteristics were observed between nondaily smokers and the two categories of smokers in young adulthood. Longitudinal analyses revealed that unorganized leisure time activities and peers' smoking differentiated nondaily smoking from nonsmoking. Higher educational achievement and less parental binge drinking predicted nondaily smoking and differentiated it from both categories of daily smoking.

conclusionsThe degree of nondaily smoking-stability from 21 to 27 years of age was modest, and most nondaily smokers quit smoking in the course of young adulthood. Young adult nondaily smokers were quite similar to nonsmokers, but differed substantially from both nicotine-dependent and nondependent daily smokers. The study suggests that nondaily smoking--at least in the absence of traditional risk factors for smoking--is usually a transitory behavior, with most people returning to nonsmoking.