Background:
Large-scale international sporting events such as the Olympic Games provide opportunities for hosting nations to promote smoke-free environments. The Olympics have been tobacco-free since 1998, but there have been few studies on the effectiveness of smoke-free Olympic policies. This study evaluated the effectiveness of smoke-free policies at the 2016 Rio Olympics, which were supported by Brazil's 2014 comprehensive smoke-free law, and measured public support for smoke-free Olympic venues.

Methods:
Data were from Waves 2-3 of the ITC Brazil Survey, a cohort survey of approximately 1200 adult smokers and 600 non-smokers in Rio de Janeiro, São Paulo, and Porto Alegre. Wave 2 (2012-13), conducted before the 2014 smoke-free law and 2016 Olympics provided the pre-policy data, and Wave 3 (2016-17) provided the post-policy data. Analyses employed GEE logistic regression models.

Results:
Of 1826 respondents surveyed in 2016-17, 116 (9.9%) smokers and 57 (14.8%) non-smokers attended the Olympics. The vast majority who attended at least one indoor event reported that smoking was banned inside venues (97.5% smokers, 93.0% non-smokers); and noticed no-smoking signs inside venues (82.2% smokers, 73.1% non-smokers). Only 10.7% of smokers and 7.2% of non-smokers noticed people smoking inside venues; 5.8% of smokers said they personally smoked at an indoor venue. Following the 2014 smoking ban and 2016 Olympics, support for the indoor smoking ban in Olympic venues increased among smokers (79.2% to 93.3%, p< .001) and non-smokers (86.4% to 94.1%, p< .001).

Conclusions:
There was strong implementation of and high compliance with Brazil's comprehensive smoking ban at the 2016 Rio Olympics. Smoke-free Olympic venues were widely supported by the public before the Games, and increased after the Games. It would be beneficial for the upcoming 2020 Tokyo Olympics organizers to consult with Rio Olympics organizers to maximize the effectiveness of any efforts to make the Tokyo Olympics smoke-free.