When do adolescents become smokers?
Objective. To follow the development of a class of pupils' tobacco habits for seven years, and to study differences in tobacco use between girls and boys. Setting. Kronoberg County in southern Sweden. Subjects. All the approximately 2000 pupils were followed from approximately age 12 to approximately age 18. Design. Yearly cross-sectional surveys from 1994 to 2000. Each year, the pupils filled in
