Background: In Sweden, the prevalence of tobacco use in the youth populatio
n differs by product and gender. but there are no longitudinal studies of v
ender differences in the uptake of smoking and use of oral snuff (OS). Meth
ods: A prospective cohort study ongoing in the County of Stockholm, encompa
ssing 3.019 children recruited in 1997 in the fifth grade of compulsory sch
ool, of whom 96% were followed-up in the sixth grade. Results: At baseline,
22% of the boys and 15% of the girls had ever smoked. respectively 8% and
3% had ever used oral moist snuff. One year later, the overall smoking prev
alence had markedly increased, as did the transition to more advanced stage
s of smoking, especially among girls. Among boys who at baseline had only u
sed oral snuff. 41% had also smoked cigarettes at follow-up. Lack of a firm
intention to abstain from tobacco use was strongly associated with onset o
f experimentation within one year, particularly among boys. Conclusions: To
bacco uptake in pre-adolescence differs between genders. with an earlier in
itiation among boys and a more rapid transition to regular smoking among gi
rls. In most cases. experimentation with oral snuff among boys marks the tr
ansition to cigarette smoking.