Background:
Smoking kills more than 27,000 people each year. In 2009, amendment of the Tobacco Hazards Prevention Act came into effect with expanded ban of smoking including all public indoor places and some public outdoor places, prohibition of all types of promotion, and a raise in tobacco taxation. This study aims to evaluate the effectiveness of this amendment on smoking rate and health inequality.

Methods:
Data were drawn from the Taiwan Adult Smoking Behavior Survey (TASBS) conducted under a nationally representative cross-sectional study with telephone interviews from 2004 to 2016. Probability proportional to size (PPS) sampling and post-stratification were used to better represent the characteristics of the population. The annual sample size is approximately 15,000-26,000 persons.

Results:
The adult smoking rate declined from 21.9% in 2008 to 15.3% in 2016, indicating a 30.3% decline in smoking rate and a reduction in the number of smokers by approximately 810,000 within 8 years. The speed of reduction in this period was more remarkable than that experienced in 4 years before the amendment. Among different subgroups, the reduction was more significant in males aged 18-29 and 65 or over than those aged 30-64, and people of lowest level of education (junior high or lower) than those of higher education.

Conclusions:
Implementation of the amended Tobacco Hazards Prevention Act has managed to remarkably reduce both smoking rate itself and inequality in smoking rates. However, continued efforts are needed to achieve the goal of a 30% relative reduction in smoking rate by 2025 set by the World Health Organization (WHO), decreasing the adult smoking rate from 20% in 2010 to 14% in 2025.