Waterpipe use predicts progression to regular cigarette smoking among Danish youth.

Waterpipe smoking among Danish, Swedish, and German youth is increasing dramatically, indicating the emergence of a new health threat. This study assessed the association between waterpipe smoking and progression to regular cigarette smoking among Danish continuation school students during 2004-2005. All participants (N = 762) had smoked cigarettes on a nonregular basis at baseline. Among boys, waterpipe smoking frequency was predictive of being a regular cigarette smoker at follow-up eight months later. Further research should examine waterpipe smoking as a potential predictor of cigarette smoking. The study's limitations are noted.