Daily tobacco smoking, heavy alcohol use, and hashish use among adolescents in southern Sweden: A population-based multilevel study

INTRODUCTION: The aim of this study was to investigate school contextual effects on daily tobacco smoking, heavy alcohol use and hashish use among adolescents, using multilevel analyses adjusting for individual-level factors. METHODS: The 2012 public health survey among adolescents in Skåne includes pupils in ninth grade in primary school (predominantly 15–16 years old) and second grade in secondary school (gymnasium) (predominantly 17–18 years old). Multilevel logistic regressions were performed. RESULTS: The prevalence of all three behaviors was higher in the second grade in the gymnasium. Several sociodemographic, psychosocial and parental factors were associated with these behaviors. In the ninth grade, variance partition coefficients (VPCs) for tobacco smoking decreased from 10.2% in the empty model to 1.9% in the fully adjusted model, for heavy alcohol use from 6.5% to 6.3%, while VPCs for hashish increased from 9.9% to 11.0%. In the second grade, VPCs for daily tobacco smoking decreased from 13.6% in the empty model to 6.5% in the fully adjusted model, VPCs for heavy alcohol use decreased from 4.6% to 1.7%, and VPCs for hashish use increased from 7.3% to 8.3%. CONCLUSIONS: Daily tobacco smoking (in both grades) and heavy alcohol use in the second grade in the gymnasium may be preventable by actions directed against individual-level protective factors including social capital, social support and peer/parent behavior and attitude, while interventions directed at school contexts may be more important for alcohol use in the ninth grade and hashish use in both grades.