Critics: San Francisco Flavor Ban Study Flawed

New research refutes a May 2021 study suggesting San Francisco’s ban on all flavored tobacco products was tied to higher smoking rates in high school students compared to school districts without flavor policies in place, according to the Truth Initiative, an antitobacco organization.  

Led by Harvard University’s School of Public Health’s Jessica Liu, the most recent research found that the data for the May 2021 study was collected too early to draw meaningful conclusions.

The San Francisco ban on flavored tobacco went into effect in July 2018. Enforcement, however, did not start until January 2019, according to the authors of the Harvard study.

The May 2021 study used data from the 2011-2019 Youth Risk Behavior Surveillance System (YRBSS) to determine smoking rates in youth after San Francisco’s flavor ban went into effect. However, the 2019 YRBSS data in San Francisco were collected between September and December 2018, before the flavor law was enforced.

Given that compliance with flavored tobacco laws was relatively low in fall 2018 (17 percent in December 2018) and that few retailers were enforcing the restriction, data collected at this time are “an inappropriate data source for evaluating the effects of the city’s flavored tobacco sales restriction,” the authors write. “…the impact on actual access to flavored products did not really start to materialize until well after the YRBSS completed data collection in San Francisco.”

Liu’s team also looked at Oakland, whose survey data on tobacco use in youth were collected after that city started enforcing a flavored tobacco ban in January 2019. Researchers observed that high school youth vaping and cigarette use declined between 2017 and 2019 in Oakland.