Effect of restrictions on smoking at home, at school, and in public places on teenage smoking: cross sectional study

Dear Editor,

Wakefield et al used a cross-sectional study to investigate the link
between smoking restrictions at home, in public places and at school, and
smoking behaviour in teenagers.

The study shows strong associations between home bans and lower
smoking uptake. However, the authors attempt to draw conclusions of
causality in the box entitled, 'What this Study adds'. While we
acknowledge the attempts made by the authors during their discussion to
recognise the limitations of this design of study, we feel that they
overstate the impact of their results here. These conclusions may be
invalid, as the questionnaire only measured smoking habit and restrictions
at a single point in time.

This is a useful study in highlighting the prevalence of smoking in
this age group and relating the extent of certain restrictions to smoking
behaviour.

Instead of using highly complex statistical analysis, better study
designs, for example cluster randomised controlled trials or time-series
studies, would provide much stronger evidence. We acknowledge the
difficulties involved in such trials, however they are clearly feasible
and would be justified in this extremely important field of research.

Victoria Bayston , Louisa Christie, Judy Fung, JoAnn Midgley, John
Nicholls

Stage 3 Medical Students

Department of Epidemiology and Public Health
University of Newcastle-upon-Tyne