Results of a recent study find that enforcing federal and state laws against tobacco sales to minors dramatically decreases underage smoking rates. The findings show that laws prohibiting sales of cigarettes to minors and increased enforcement of those laws in the United States have led to a 20.8% drop in the odds of 10th graders becoming daily smokers.

"Skeptics argued that prohibiting sales to minors wouldn’t help, because kids would always be able to get cigarettes somewhere," says Joseph DiFranza, MD, professor of family medicine and community health at the University of Massachusetts Medical School. "This study clearly demonstrates that enforcing these laws reduces smoking rates among youth."

This is the first nationwide review to show that laws prohibiting retailers from selling cigarettes to underage youth are working as intended. Earlier, smaller-scale studies on the effectiveness of laws on cigarette sales to minors were inconclusive, partly because of lax penalties and uneven enforcement.

To conduct the study, researchers reviewed enforcement of the laws between 1997 and 2003, after Congress passed the Synar Amendment in 1996, which required states to pass and enforce laws barring tobacco sales to minors for the first time. The Synar Amendment also forced states to monitor compliance by sending underage decoys into stores to try to purchase tobacco.

An analysis of the nationwide compliance data was compared with smoking rates among a nationally representative sample of 16,244 adolescents from the 2003 Monitoring the Future survey. The researchers concluded that for every 1% increase in the rate of merchant compliance with the laws, daily smoking rates among 10th graders fell by 2%.

"Our data suggest that a 25% increase in compliance of laws prohibiting cigarette sales to minors has about the same deterrent effect as increasing the price by $2.00 in 2006 dollars," says DiFranza. "We need to continue to raise tobacco taxes and improve compliance on laws preventing cigarette sales to minors as a part of a comprehensive approach to reducing smoking rates among youth."

The study appears in the current issue of the journal BMC Public Health.