A longitudinal study of policy effect (smoke-free legislation) on smoking norms: ITC Scotland/United Kingdom

Introduction: The longitudinal ITC Scotland/U.K. survey was used to investigate adult smokers' support for smoke-free legislation and whether this support was associated with higher quit intentions at follow-up, either directly or indirectly, via the mediation of perceived social unacceptability of smoking. Methods: Structural equation modeling was employed to compare differences between the two samples (507 adult smokers from Scotland and 507 from the rest of the United Kingdom) across two waves (February/March 2006 and March 2007). During these two waves, a smoking ban was introduced in Scotland but not the rest of the United Kingdom. Results: For smokers in both samples, support for smoke-free legislation at baseline significantly heightened perceived unacceptability of smoking, although perceptions of unacceptability were somewhat stronger in Scotland than the rest of the United Kingdom postban. Unlike the rest of the United Kingdom, support for a ban at baseline among smokers in Scotland was associated with higher quit intentions at follow-up. For both samples, quit intentions were significantly associated with heightened perceived unacceptability at follow-up. The overall variance explained in quit intentions was greater in Scotland than in the rest of the United Kingdom but not significantly so. Discussion: Support for smoke-free legislation at baseline significantly increased support at follow-up for both samples. However, this did not independently increase quit intentions among smokers from both Scotland and the rest of the United Kingdom. The findings suggest that normative influences are one of the mechanisms through which comprehensive smoke-free legislation influences quit intentions.