(CNN) -- The public health benefits of barring people under age 21 from buying cigarettes could be tremendous, including "4.2 million fewer years of life lost" among the next generation of American adults, according to a report released this week by the Institute of Medicine.
Setting the minimum age at 21 nationwide, the report estimates, would result in nearly a quarter-million fewer premature deaths and 50,000 fewer deaths from lung cancer among people born between 2000 and 2019.
The study, conducted at the request of the U.S. Food and Drug Administration, compared the predicted benefits of raising the minimum legal age for buying tobacco products -- currently 18 in most states -- to 19, 21, and 25 years. It concludes that the greatest benefits would arise if the legal age nationwide were 25, at which point the prevalence of smokers among today's teens, when they become adults, would decline by 16%.
Predicted smoking prevalence falls an estimated 12% with the minimum age set at 21, and only 3% if set at 19, according to the report, titled "Public Health Implications of Raising the Minimum Age of Legal Access to Tobacco Products."
Even though fewer teenagers are using tobacco than ever before, more than half of current smokers say they started smoking before they were 18, according to the report.
Teenagers, especially those between ages 15 and 17, are most vulnerable to addiction at a time when their brains are still developing, the report notes, and would be the group that benefits most from raising the minimum age of legal access (MLA) more in line with the minimum age to buy alcohol.
It says that raising the minimum age to 21 or 25, rather than just to 19, would greatly reduce the number of people younger than 18 who are introduced to tobacco through "social sources" such as co-workers or friends.
The study was conducted by a committee of experts who reviewed "existing literature on tobacco use initiation, developmental biology and psychology and tobacco policy" and used mathematical modeling to arrive at their predictions, the report states.
Chris Hansen of the American Cancer Society's Cancer Action Network praised the report, saying "powerful interventions are needed to keep youth from lifelong addictions to these deadly products."
The American Academy of Pediatrics issued a statement calling the report "a crucial contribution to the debate on tobacco access for young people."
"There is no safe way to use tobacco," said Dr. Sandra G. Hassink, the academy's president.
The report notes that the FDA, which requested the study in 2013, cannot raise the age limit nationwide. While the report serves as a call to action in ending the leading cause of preventable death in the United States, it makes no recommendation on raising the MLA.
"The public health impact of raising the MLA for tobacco products depends on the degree to which local and state governments change their policies," the report says. "These decisions will depend on each state's or locality's balance between personal interests and the privacy of young adults to make their own choices versus society's legitimate concerns about protecting public health."
The MLA in four states is 19, and several local jurisdictions -- including New York City last year -- have raised the legal age to 21, according to the report.
The tobacco industry, which historically has called for "responsible" consumption of tobacco products, is waiting for input from the federal government.
Brian May, a spokesman for Altria Group, which owns Philip Morris -- the maker of Marlboro cigarettes -- wrote to CNN saying, "This is a complex issue and Congress has established a thoughtful process to better understand it. We believe states and localities should defer to this process and allow FDA and Congress the opportunity to think through this issue further before enacting different minimum age laws."
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