When San Francisco voters overwhelmingly approved a ballot measure banning the sale of flavored tobacco products in 2018, public health advocates celebrated. After all, tobacco use poses a significant threat to public health and health equity, and flavors are particularly attractive to youth.
But according to a new study from the Yale School of Public Health (YSPH), that law may have had the opposite effect. Analyses found that, after the ban’s implementation, high school students’ odds of smoking conventional cigarettes doubled in San Francisco’s school district relative to trends in districts without the ban, even when adjusting for individual demographics and other tobacco policies.

The study, published in JAMA Pediatrics on May 24, is believed to be the first to assess how complete flavor bans affect youth smoking habits.
“These findings suggest a need for caution,” said Abigail Friedman, the study’s author and an assistant professor of health policy at YSPH. “While neither smoking cigarettes nor vaping nicotine are safe per se, the bulk of current evidence indicates substantially greater harms from smoking, which is responsible for nearly one in five adult deaths annually. Even if it is well-intentioned, a law that increases youth smoking could pose a threat to public health.”