The implementation of smoke-free legislation in Wisconsin was associated with a statistically significant decline in reported exposure to tobacco smoke outside the home, inside the home, and at work among SHOW participants. These results are consistent with those of previous studies on the effects of smoke-free legislation in parts of Europe, Canada, and the United States.1
For example, a phone interview study conducted in Ontario, Canada that evaluated whether smoking bans affect rates of secondhand smoke exposure also found that smoke-free legislation was associated with decreased exposure in public places, the home, and in the workplaces of its survey participants.13
It is noteworthy that our results showed that smoke-free legislation in Wisconsin was associated with a decrease in secondhand smoke exposure not only in public places, but also in the home; it also was associated with an increase in prevalence of no-smoking policies in the households of Wisconsin residents. According to our results, only 20.4% of households in Wisconsin did not have a strict no-smoking policy after 2009 Wisconsin Act 12 went into effect. This number is much lower than the 1999 estimate provided by the Centers for Disease Control and Prevention, which showed that 55.3% of Wisconsin households in 1999 did not have smoking policies.14
Most previous studies on the effects of smoke-free legislation on secondhand smoke exposure in the home did not find the association seen in our results. A study conducted in Hong Kong before and after the implementation of smoke-free legislation in 2007 found that such legislation increased smoke exposure in the home.15
A review by Callinan et al found that smoke-free legislation generally was not associated with a decrease in secondhand smoke exposure in the home.1
Similar results to this review article also were found in a study conducted in Scotland in 2006.16
A telephone interview study conducted in Ireland after implementation of its smoke-free legislation in 2004 found that 71% of Irish smokers reported that the legislation did not affect their smoking behaviors in the home, 22% reported that it had caused them to place stronger home smoking restrictions, and 6% reported smoking more in their homes.17
In contrast, a study conducted in Scotland before and after the implementation of smoke-free legislation found that the legislation had increased home smoking restrictions.4
Further research is needed to reconcile these different findings on the effects of smoke-free legislation on smoking behaviors in the household.
With regard to changing the smoking behaviors of Wisconsin residents, in the short time since its implementation, 2009 Wisconsin Act 12 did not appear to be associated with a reduction in smoking prevalence or in the number of current smokers who wanted to completely quit or were considering quitting. Furthermore, we only found a slight, non-statistically significant reduction in the mean number of cigarettes smoked among current smokers in our study sample. Previous studies reporting on these outcomes have not been entirely consistent. For example, a study conducted in the town of Bury, England in 2007 found that England’s smoke-free legislation did not affect smoking prevalence but did decrease the number of cigarettes smoked among current smokers.18
Other studies conducted in Canada, Italy, and the United States found that smoke-free legislation significantly decreased smoking prevalence by as little as 1.9% and as much as 14.4%.2,5–7,19
It is important to note that some of these studies had much larger sample sizes. The number of current smokers in the SHOW data so far was only 167, a number that limits the statistical power of the study when it comes to analyzing the effects of the law on smoking prevalence and on the behaviors of current smokers. It is also possible that more time is required for this kind of legislation to have an effect on active smoking behaviors. As the sample size of the SHOW data and the time since the new legislation increases over the coming years it will be possible to analyze the effects of 2009 Wisconsin Act 12 on smoking behaviors with greater statistical power.
Our results also demonstrate that 2009 Wisconsin Act 12 generally had a larger impact on exposure to smoke among Wisconsin residents who were older, wealthier, and more educated. When it comes to exposure to smoke outside the home, at work, and at home, the 61–74-year-old age group had the largest reduction after the implementation of 2009 Wisconsin Act 12. Participants with a family income greater than $60,000 per year also reported the largest reduction in exposure to smoke outside and inside the home, while the middle income group ($30,000–$59,999 per year) reported the largest reduction in exposure to smoke at work. The reduction in exposure to smoke outside the home and at work was about the same in both education groups but a larger reduction was seen in exposure to smoke at home in the group with a college education or higher. Those in the higher education group were also more likely to have a strict no-smoking ban in the home. A study conducted in the United States, Canada, the United Kingdom, and Australia regarding socioeconomic and country variations in smokers’ knowledge found that higher education and income were associated with higher awareness of the negative effects of smoking.19
The authors of this study explained this association by suggesting that such differences might exist because those who are wealthier and more educated have a wider knowledge of and access to sources of information. This can therefore make these groups more capable of reaping the benefits of laws such as 2009 Wisconsin Act 12 earlier and may explain the variation seen in our results among different income and educational groups. However, further research is needed to understand why differences based on socioeconomic variation were found in the current study.