The Differential Impact of the 2000 Canadian Graphic Warning Label Policy on Smoking Prevalence by Sex and Education: A Difference-in-Difference-in-Difference Model.

Existing evidence shows that GWL implementation is associated with reductions in smoking prevalence. But there is limited evidence from past evaluation studies on whether the impact of GWLs on smoking prevalence differs by sociodemographic subgroup. Our findings confirm existing studies that the 2000 implementation of GWLs in Canada was significantly associated with an overall reduction in smoking prevalence in Canada compared to the United States. However, our study improves existing evidence by showing that the impact of the Canadian GWLs on smoking prevalence did not differ by sex or education, and thus did not reduce existing smoking disparities by educational levels.