摘要：Objectives. We assessed attitudes and beliefs about smoke-free laws, compliance, and secondhand smoke exposure before and after implementation of a comprehensive smoke-free law in Mexico City. Methods. Trends and odds of change in attitudes and beliefs were analyzed across 3 representative surveys of Mexico City inhabitants: before implementation of the policy (n = 800), 4 months after implementation (n = 961), and 8 months after implementation (n = 761). Results. Results indicated high and increasing support for 100% smoke-free policies, although support did not increase for smoke-free bars. Agreement that such policies improved health and reinforced rights was high before policy implementation and increased thereafter. Social unacceptability of smoking increased substantially, although 25% of nonsmokers and 50% of smokers agreed with smokers' rights to smoke in public places at the final survey wave. Secondhand smoke exposure declined generally as well as in venues covered by the law, although compliance was incomplete, especially in bars. Conclusions. Comprehensive smoke-free legislation in Mexico City has been relatively successful, with changes in perceptions and behavior consistent with those revealed by studies conducted in high-income countries. Normative changes may prime populations for additional tobacco control interventions. Smoke-free policies can reduce involuntary exposure to toxic secondhand tobacco smoke (SHS), reduce tobacco consumption and promote quitting, 1 , 2 and shift social norms against smoking. 3 – 5 These policies are fundamental to the World Health Organization's Framework Convention on Tobacco Control, an international treaty that promotes best-practices tobacco control policies across the world. 6 Evidence of successful implementation of smoke-free policies generally comes from high-income countries. Low- and middle-income countries increasingly bear the burden of tobacco use, 7 however, and these countries may face particular challenges in implementing smoke-free policies, including greater social acceptability of tobacco use, shorter histories of programs and policies to combat tobacco-related dangers, and greater tolerance of law breaking. 8 – 10 There is a need for research that will help identify effective strategies for promoting and implementing smoke-free policies in low- and middle-income countries. Studies in high-income countries generally indicate that popular support for laws that ban smoking in public places and workplaces is strong and increases after such laws are passed. 11 – 15 Weaker laws that allow smoking in some workplaces can leave policy support unchanged. 16 Policy-associated increases in support have been shown across populations that include smokers 11 , 13 , 14 , 17 , 18 and bar owners and staff. 19 , 20 Beliefs about rights to work in smoke-free environments 11 and the health benefits of these environments 21 have also been shown to increase with policy implementation. Support for banning smoking in all workplaces appears high in Latin American countries, 22 but responses to smoke-free policies are less well known. In Uruguay, the first country in the Americas to prohibit smoking in all workplaces, including restaurants and bars, 23 support before the law was unknown. However, the level of support was high among both the general population 22 and smokers 24 after the law's implementation. Compliance with smoke-free laws in high-income countries has been good, particularly when laws apply across all workplaces, including restaurants and bars, and involve media campaigns. Self-reported declines in exposure in regulated venues 11 , 17 , 25 are consistent with findings from observational studies, 11 , 26 biomarkers of exposure, 11 , 25 , 27 and air quality assessments. 11 , 12 Approximately 26% of Mexican adults residing in urban areas smoke. 8 Most Mexicans recognize the harms of SHS and support smoke-free policies. 9 , 24 , 28 , 29 According to an opinion poll conducted before the August 2007 passage of a smoke-free law in Mexico City, about 80% of both Mexico City inhabitants and Mexicans in general supported prohibiting smoking in enclosed public places and workplaces. 28 In 2006, 60% of smokers reported that their workplace had a smoking ban, with Mexico City smokers reporting the lowest percentage of workplace bans at 37%. 24 Mexico City's smoke-free workplace law 30 – 32 initially allowed for designated smoking areas that were ventilated and physically separate. 22 , 33 Concerns about the inequity of this law for small business owners who could not afford to build designated smoking areas led the hospitality industry to support a comprehensive smoke-free law 31 , 32 that prohibited smoking inside all enclosed public places and workplaces, including public transport, restaurants, and bars. This law entered into force on April 3, 2008. Media coverage of the law was similar to that in high-income countries, pitting arguments about the government's obligation to protect citizens from SHS dangers against arguments about discrimination toward smokers and the “slippery slope” of regulating behavior 4 , 32 , 34 (J. F. Thrasher et al., unpublished data, 2010). Most print media coverage was either positive or neutral, with much less coverage pitched against tobacco control policies. 34 In the month before and after the law came into effect, the Mexico City Ministry of Health and nongovernmental organizations disseminated print materials and aired radio spots describing the dangers of SHS and the benefits of the law. 30 Community health promoters informed businesses about the law. From September through December 2008, a television, radio, print, and billboard campaign emphasized the law's benefits. 35 We assessed, among Mexico City inhabitants, the prevalence of and increases in support, beliefs, norms, and compliance around the smoke-free law, as well as decreases in SHS exposure.
