Purpose: To assess the associations among smoking, alcohol use, and physical activity, and to assess how the health behaviors predict changes in other health behaviors from adolescence to adulthood.
Methods: Subjects were the participants of the North Karelia Youth Project study from six schools in Eastern Finland. At the baseline in 1978 they were 13-year-olds (n = 903) and in the last of the six surveys in 1993 they were 28-year-olds. This study uses the data from three surveys in which the participants were 15-, 21-, and 28-year olds. The response rate was 71% in the last survey. Data were analysed by SPSS software.
Results: Smoking prevalence was highest at the age of 21 years and alcohol use at the age of 28 years. The prevalence of leisure-time physical activity did not change much over time. Smoking and alcohol use correlated positively for each survey. Smoking correlated negatively with leisure-time physical activity. The best predictors for each health behavior were the same behaviors measured before, but smoking had the strongest level of continuity. In addition, alcohol use at the age of 15 years predicted smoking at the ages of 21 years and 28 years, but smoking in adolescence did not predict alcohol use in adulthood.
Conclusions: Smoking was associated with both alcohol use and physical activity and therefore has a central role among health behaviors. Smoking and alcohol use were particularly clearly related from adolescence to adulthood. Smoking behavior was the most constant behavior.