Abstract
The data on long-term trends and factors of tobacco retailers' compliance in Taiwan are limited. The new regulations of the Tobacco Hazards Prevention Act were established in 2009. Now, the government is planning to raise the minimum legal age (MLA) for purchasing tobacco products from 18 to 20, so the results of this study will be an important reference to promote new regulations in the future. We carried out an observational mystery shopping study design and data were collected from 2009 to 2019. In total, 6320 undercover tests were conducted to investigate selling by tobacco retailers to persons aged less than 18 years by an impartial third party annually. Logistic regression was used to analyze the factors influencing compliance by adjusting test variables and independent variables. The compliance rate increased by 8.4% annually and was better among tests conducted during summer vacation (AOR = 1.324), chain convenience stores (AOR = 3.651), supermarkets or hypermarkets (AOR = 1.973), and verifications with age (AOR = 15.345). It is the first study to explore long-term and national tobacco retailers' enforcement effects by an impartial third party in Asia. The findings suggest that local health agencies should enhance enforcement on those stores which were tested during non-summer holidays and weekends, betel nut stands, and grocery stores.