Taxation reduces social disparities in adult smoking prevalence.

Background: The CDC, the WHO, and the World Bank promote increases in the price of cigarettes as an effective and important tobacco-control strategy. This study was designed to assess the extent to which the association between the price of cigarettes and smoking prevalence, as measured monthly, varies by income group.
Methods: Australian population survey data collected monthly from January 1991 to December 2006 were used to estimate Poisson regression models to assess the impact of the price of cigarettes on smoking prevalence across three income groups. Analyses were conducted in 2008.
Results: There was strong evidence that real price and prevalence were negatively associated (p<0.001) and that the association was stronger in lower-income groups (p<0.001). One Australian dollar increase in price was associated with a decline of 2.6%, 0.3%, and 0.2% in the prevalence of smoking among low-, medium-, and high-income groups, respectively.
Conclusions: Increasing the price of cigarettes not only is an effective tobacco-control strategy to lower smoking prevalence in the general population, but also may provide a means of reducing social disparities in smoking.