Enforcement of laws against the sale of cigarettes to minors does result in a reduction in underage smoking. Research published in the open access journal BMC Public Health provides the first evidence that enforcement programmes can be effective on a national scale.
Joseph DiFranza led a team of researchers from the University of Massachusetts Medical School who investigated the effects of the Synar Amendment, a law passed in the United States in 1996 that compels local authorities to carry out 'decoy shopper' tests on tobacco retailers.
He said, "The impact of tobacco sales law enforcement has never before been evaluated in a national study. As states complied with the Synar Amendment, there was a 20.8% reduction in daily smoking among 10th graders, after controlling for other factors".
By making it financially dangerous for shops to sell tobacco to underage customers, cigarette supply to this vulnerable group is reduced. The authors found that the main reductions were seen in the 'daily smokers' group; but reductions in the number of occasional smokers are also expected.
According to DiFranza, "Novice smokers obtain their cigarettes by begging from friends and do not typically spend their own money until they feel a need to smoke every day. Daily smokers make most purchases and win friends by supplying peers with cigarettes. Thwarting the sale of tobacco to youth affects daily smokers directly and nondaily smokers mostly indirectly as their friends become less willing to share when it becomes difficult for them to purchase".
The cost to government of enforcing the law is around $150 per retailer per year. The authors point out that an extra two-cent tax on tobacco products would be sufficient to fund a comprehensive enforcement system. Cigarette price increases were estimated to be about twice as effective as sales enforcement in reducing underage smoking, but, as the authors conclude, "There is no reason why policy makers should choose between these approaches - all effective measures to reduce smoking among youth should be employed".