April 16 (HealthDay News) -- American adolescents who live in states that comply with tobacco sales laws are less likely to pick up a smoking habit than are those who live where the laws are not vigorously enforced, a new study has found.
And raising the price of a pack of cigarettes might have an equal, if not greater, effect, the study also showed.
"Efforts to prevent the sale of tobacco to children pay off," said study author Dr. Joseph R. DiFranza, a professor of family medicine and community health at the University of Massachusetts Medical School. "It's very effective at reducing the number of kids who smoke."
Since 1992, states have been required to prohibit the sale and distribution of tobacco to minors. But in 1996, the U.S. Substance Abuse and Mental Health Services Administration issued a regulation that, in essence, put some teeth into the legislation that requires states to pass and enforce so-called no-sale laws.
Though there has been some debate about the effectiveness of the congressional mandate, a growing body of evidence demonstrates that enforcing existing laws reduces the number of adolescent smokers.
DiFranza and his colleagues analyzed data from a 2003 survey of 16,244 adolescents, nearly all 15 to 17 years old, to obtain information on smoking habits. In addition, they looked at state-collected data on merchants' compliance with anti-tobacco laws. Then they correlated the data, taking into account such factors as cigarette prices, restaurant smoking policies, anti-smoking campaigns and demographic information that included age, gender, race, ethnicity and parents' education level.
The researchers found that, as merchants more diligently enforced the ban on tobacco sales to minors and as the price of cigarettes rose, the likelihood of teens smoking dropped.
Improved compliance with the laws from 1997 to 2003 was credited with about a 21 percent decline in the likelihood of a teen smoking. Price increases for a pack of cigarettes during that time reduced the odds by about 47 percent, the study found.
The results appear online April 17 in the journal BMC Public Health.
"Cigarette smoking is a major contributor to many of the chronic diseases that we see in society today -- cardiovascular disease, cancer, dementia and other forms of cognitive decline and low birth weight," said Dr. Ted Schettler, science director at the Science & Environmental Health Network in Ames, Iowa. "And adolescent smoking increases the risk of lifelong smoking."
According to the American Lung Association, about 90 percent of smokers started before age 21, and an estimated 4.5 million U.S. adolescents smoke.
"Up until now, it's been controversial about whether all the effort put into enforcing the law has been worthwhile or not," DiFranza said. "Some people had made halfhearted efforts to obey the law, and those have not worked at reducing either the number of stores that sell tobacco to kids or the number of kids that smoke."
The finding from DiFranza's study mirrors that from a study published this month on the effect of laws targeting the sale of alcohol to minors.
In that study, states that had enacted more punitive laws -- including use-and-lose laws that allow the suspension of a driver's license for any underage alcohol violation and zero-tolerance laws that make it illegal for young people to drive with any amount of alcohol in their system -- had fewer drinking-related fatalities among teens than did states that did not have such laws. The results were published in the April 7 issue of Alcoholism: Clinical and Experimental Research.
"In the past, we've had success in reducing the number of teens who smoke by enforcing these laws in communities, but this is the first study to show that it works at the national level," DiFranza said. "It's important to show that this strategy works across the whole geography of the United States, in rural and urban areas."
Schettler said that it's important to note "that many of these strategies go well beyond just advising people not to smoke and really get into more systemic public health interventions and trying to create, at the societal level, barriers to smoking."
SOURCES: Joseph DiFranza, M.D., professor, family medicine and community health, University of Massachusetts Medical School, Worcester, Mass.; Ted Schettler, M.D., M.P.H., science director, Science & Environmental Health Network, Ames, Iowa; April 17, 2009, BMC Public Health, online