As Gov. Jerry Brown ponders whether to sign into law a bill raising California's smoking age from 18 to 21, he will have little solid research on which to base his decision. But one large study predicts that making this change will lead to a significant decline in youth smoking rates and smoking-related illnesses.
State lawmakers gave final approval to the smoking age measure Thursday. If Brown signs it, California will be the second state after Hawaii to raise its smoking age to 21. The legislature also sent the governor a measure that would regulate electronic cigarettes the same as tobacco.
At least 135 municipalities in nine states – including New York, which acted in 2014, and San Francisco, which approved the change last week – have increased the minimum legal age to buy tobacco products to 21, according to the Campaign for Tobacco-Free Kids.
There has been almost no research measuring whether those areas have experienced a drop in the number of young people taking up smoking. A study of one town, Needham, Massachusetts, did find a sharp reduction in teen smoking rates after the municipality raised the smoking age to 21.
The strongest evidence suggesting that this approach could work comes from the Institute of Medicine. In a March 2015 report, a committee of experts convened by the Institute predicted that boosting the minimum age of legal access to tobacco products to 21 would lead to a 12 percent decrease in smoking prevalence among teens and young adults. It would also likely result in fewer premature deaths and lung cancer deaths, the committee concluded.
The study said all of this would occur in large part for a simple reason: Twenty-one-year-olds "are less likely to be in the same social networks as high school students." In other words, it would be harder for teens to find a friend of legal age to buy cigarettes for them.
The Institute, which convened its experts at the request of the Food and Drug Administration, said its predictions were based on a review of "existing literature on tobacco use initiation, developmental biology and psychology, and tobacco policy." It used "mathematical modeling to quantify these predictions."
Among adults who are daily smokers today, about 90 percent started smoking before they turned 19, and almost 100 percent started smoking before age 26, according to the report.
"We know the longer you go without smoking, the less likely you are to take up the habit," says Dr. Rob Crane, a professor at The Ohio State University and president of the Preventing Tobacco Addiction Foundation.
The town of Needham raised its smoking age to 21 in 2005. Between 2006 and 2010, the percentage of the town's high school students who reported smoking in the previous 30 days decreased by 46 percent, according to a June 2015 study published in BMJ. Sixteen nearby communities with a smoking age of 18 reported a decrease in teen smoking of just 20 percent, according to the study, which was based on surveys of more than 16,000 high school students.
From 2010 to 2012, the surrounding towns experienced larger decreases in teen smoking, but their rates remained higher than those in Needham.
"I'm still surprised that it worked as well as it did, because Needham is so small," Crane says.