Background:
Quitting tobacco use can reduce smokers' risks for disease and premature death. We used the trans-theoretical behavior change model to examine temporal differences in readiness to quit smoking among adults in five countries.

Methods:
We analyzed two independent samples from the Global Adult Tobacco Survey, a standardized national adult household survey of persons aged ≥15 years, for five countries: Mexico (2009, 2015), Philippines (2010, 2016), Thailand (2009, 2011), Turkey (2008, 2012), and Vietnam (2010, 2016). Response rates ranged 82.5%-96.3% and sample sizes ranged 8,996-20,606. Current smokers were defined as adults who smoked tobacco on a daily or non-daily basis. Using responses to questions assessing intention to quit cigarette smoking, we categorized current smokers into the following stages of change: pre-contemplation, contemplation, and preparation. Relative change was compared using z-tests (p< 0.05).

Results:
No significant change in smoking prevalence between wave 1 and 2 occurred for Mexico (15.9% to 16.4%), Thailand (23.7% to 24.0%), or Vietnam (23.8% to 22.5%). In contrast, smoking prevalence declined for Philippines (28.2% to 22.7%) and Turkey (31.2% to 27.1%). There was an increase in the proportion of smokers in the pre-contemplation stage in Thailand (76.1% to 85.4%) and Vietnam (70.8% to 82.3%), while a decline occurred in Turkey (31.2% to 27.1%); no significant change occurred in Mexico or Philippines. The proportion of smokers in the contemplation stage declined in Thailand (17.6% to 12.0%) and Vietnam (21.6% to 14.1%), but increased in Turkey (21.2% to 26.9%); no significant change occurred in Mexico or Philippines. The proportion in the preparation stage declined in Thailand (6.3% to 2.6%) and Vietnam (7.6% to 3.6%); no significant changes occurred in, Mexico, Philippines, or Turkey.

Conclusions:
Using the stages of change model, smokers' readiness to quit varies by country. Tailored interventions towards specific stages of cessation might help motivate quitting behavior.