WELL; Debating Age Limits On Tobacco
By NICHOLAS BAKALAR
Published: April 30, 2013
The New York City Council has taken up a proposal to raise the minimum age for tobacco purchases to 21 from 18, the strictest such limits in any major American city.
Smoking declined significantly among the city’s teenagers from 2005 to 2007, then remained level through 2012, and Christine C. Quinn, the City Council speaker, has cited “clear data” showing that 80 percent of smokers begin before age 21.
“We have an ability to intervene on that and make a difference,” Ms. Quinn said last week at a news conference last week.
But the scientific picture is a bit murkier than it might seem. While most tobacco researchers agree that age restrictions will do no harm and may well help reduce the incidence of smoking among teenagers, firm scientific proof for their effectiveness is hard to come by.
In 2007, the minimum age for buying tobacco in Britain was raised to 18 from 16. The new limit had some beneficial effect, according to two studies cited by Ms. Quinn and Dr. Thomas A. Farley, the city’s health commissioner. In the first, published in October 2011 in the journal Thorax, a survey of 7,798 students ages 11 to 15 found that the law reduced the number who reported smoking at least one cigarette a week.
But the data did not include 16- and 17-year-olds, presumably the teenagers most affected by the change. The authors acknowledged that “the sample size did not permit us to examine whether the legislation reduced the volume of cigarettes smoked.”
The second British study, published in the November 2010 issue of Addiction, also depended on self-reports and found that smoking decreased more in 16- and 17-year olds than in any other age group after implementation of the 2007 law. But smoking decreased in all age groups, the authors noted, suggesting that raising the minimum purchase age could not have been the only factor at work.
One study, published in 2007 in Tobacco Control, was a two-year prospective analysis of a random sample of 2,623 teenagers in Massachusetts; the researchers linked self-reported teenage smoking to a statewide database of smoking laws and enforcement practices.
The study found that varying laws and levels of enforcement made no difference in the rate of teenagers taking up smoking, although the authors acknowledged that other antismoking initiatives during the period could have hidden the effect.
Amanda Amos, a professor of health promotion at the University of Edinburgh who has published widely on teenage smoking, agreed that the data on whether age laws work is not completely convincing.
“When you look at the evidence about whether it actually decreases smoking, that’s not so clear,” Dr. Amos said. “There is some evidence that you can tighten up on sales, but then young people find other sources.”
Dr. Farley is more optimistic. “I would characterize the evidence as quite positive,” he said. “The two that are the strongest are the study in England where they showed a big decline, and the data from Needham, which shows a remarkable decline over six years which was not matched here or anywhere else.”
Needham, a town in Massachusetts, raised the minimum sale age to 21 in 2005. According to a health survey conducted in 24 high schools in the region, 5.5 percent of Needham students were smokers in 2012, down from 12.9 percent in 2006.
What might account for the varied results in these studies? “A lot of the studies have found that the direct impact depends on enforcement,” Dr. Amos said. “The more you put into enforcement, the better it works.”
The new law does not change the penalties to retailers for selling to underage customers, nor does it criminalize smoking or the possession of cigarettes by people under 21.
“All studies have their weaknesses,” Dr. Farley said. “You can’t do randomized controlled trials of a law. The closest you get is where you track over time the thing you expect to change and compare it to the places where you didn’t change the law. The data is pretty solid, and it makes all the sense in the world.”
This is a more complete version of the story than the one that appeared in print.