Differential impact of local and federal smoke-free legislation in Mexico: a longitudinal study among adult smokers.

OBJECTIVE To assess the impact of Mexico City and federal smoke-free legislation on secondhand tobacco smoke (SHS) exposure and support for smoke-free laws. MATERIAL AND METHODS Pre- and post-law data were analyzed from a cohort of adult smokers who participated in the International Tobacco Control (ITC) Policy Evaluation Suvey in four Mexican cities. For each indicator, we estimated prevalence, changes in prevalence, and between-city differences in rates of change. RESULTS Self-reported exposure to smoke-free media campaigns generally increased more dramatically in Mexico City. Support for prohibiting smoking in regulated venues increased overall, but at a greater rate in Mexico City than in other cities. In bars and restaurants/cafés, self-reported SHS exposure had significantly greater decreases in Mexico City than in other cities; however, workplace exposure decreased in Tijuana and Guadalajara, but not in Mexico City or Ciudad Juárez. CONCLUSIONS Although federal smoke-free legislation was associated with important changes smoke-free policy impact, the comprehensive smoke-free law in Mexico City was generally accompanied by a greater rate of change.