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Authors: J Thrasher, R Perez-Hernandez, K Swayamkapala, E Arillo-Santillan, M Bottai

Reference: Am J Public Health, published online 13 May 2010
http://ajph.aphapublications.org/cgi/content/abstract/AJPH.2009.180950v1

Reviewer: Joaquin Barnoya, MD, MPH, Contributing Editor, ProCor; Research Assistant, Professor of Surgery, Washington University in St. Louis, Missouri, USA; Director, Research and Education, Unidad de Cirugia Cardiovascular de Guatemala, Guatemala

Comments: Since 2008, Mexico City has enjoyed smoke-free environments. From this population-based survey, popular support for the law is evident. As with every social norm change, acceptability is gradual and is expected to increase over time. Especially among smokers, it will be interesting to assess how support changes and how the law helps them quit or reduce the number of cigarettes smoked per day.

We welcome your comments.

Purpose of study: To assess attitudes and beliefs about smoke-free laws, compliance, and secondhand smoke (SHS) exposure before and after the implementation of a smoke-free law in Mexico City.

Location of study: Mexico City, Mexico

Study design: This analysis includes data from population-based samples of Mexico City. The first sample includes 800 participants surveyed two weeks before the law was implemented. Four months after the law was implemented 961 participants were surveyed. One last survey was conducted among 761 participants eight months after implementation. Support for smoke-free venues was assessed through standard items. Two items assessed the perceived health benefits of smoke-free workplaces. Likert-scale response options ranged from "strongly agree" to "strongly disagree". Participants who worked in an enclosed environment were asked how often people had smoked inside in the past 30 days.

Results: Most (82%) people who participated in the first post-law survey were successfully followed up. In all three surveys most respondents (smokers or nonsmokers) agreed with the smoke-free law (78% prelaw and 88% second post-law survey). Agreement was lowest for bars and highest for workplaces in all the surveys. Increases (particularly among nonsmokers) were significant across almost all indicators of support, beliefs, and norms in favor of the law. Among nonsmokers, support for banning smoking in bars rose from 68% pre-law to 79% in the last survey (p<0.001). The corresponding percentages for smokers were 45% to 41% (p=0.2). Crude and adjusted odds over time yield a significant decrease in SHS exposure across all venues. Over the survey period, the percentage of participants exposed daily to SHS decreased from 28% to 14%.