The smoking rate for adults in the USA dipped last year after a seven-year stall, a new government report says. It's too early to tell why.
Smoking rates have declined steadily for decades, according to the report by the Centers for Disease Control and Prevention (CDC). Last year's decrease - down to 18% - ends a smoking rate stall that hovered at 20% to 21% for more than seven years, then froze at about 19% in 2010 and 2011.
"We are a long way from the end game on tobacco use," says Thomas Novotny, professor of global health at San Diego State University. "It is too early to declare victory."
Smoking is the leading cause of preventable illness and death in the USA, accounting for one in five deaths and direct medical costs ranging from $50 billion-$73 billion per year, the CDC says. It causes more than 80% of all lung cancer deaths and coronary heart disease, the leading cause of death in the country, according to a CDC report.
It's unclear what caused last year's smoking rate to decline. Historically, rising taxes on tobacco products, smoking restrictions and mass media and school-based educational campaigns have helped push down the smoking rate, says Joshua Yang, a tobacco control researcher at the University of California-San Francisco.
The preliminary report, released Tuesday, did not include data on teens. The rate was about 9% for adults over 65 compared with about 20% for all other adults. Men are more likely to smoke than women across all age groups.
The data were collected from a survey of 35,000 U.S. adults. Adults who have smoked more than 100 cigarettes in their lifetime and smoke every day or some days are considered smokers.
Almost half of states require smoke-free indoor air, a well-studied deterrent to smoking, says Richard Grucza, an associate professor of psychiatry at Washington University. He says declines could be the result of stricter tobacco control policies.
Last year, the CDC launched a controversial advertising campaign featuring graphic photos, stories and videos of smokers to budge the smoking rate down. The TV and radio spots triggered 200,000 additional calls by smokers about quitting, according to the CDC.
Yang acknowledges the significance of the CDC's effort - one of the agency's most graphic and largest anti-smoking campaigns - but says other tobacco control efforts can't be discounted.
Increases in cigarette prices reduce smoking rates significantly, especially for adolescents. A 10% price increase can cut overall cigarette consumption in young adults by about 4%, according to the CDC.
States with more restrictive limits on teenagers purchasing tobacco also have lower adult smoking rates, especially among women, according to a Washington University study published in the American Journal of Public Health on June 13.
TV and movie characters may be smoking less, too, reducing the influence of mass media on viewers. A 2013 study by the Norris Cotton Cancer Center and Dartmouth College found that the Master Settlement Agreement (MSA) - a 1998 agreement between state attorneys general that banned the tobacco industry from product advertising on TV and in movies - led to an exponential decline in the appearance of tobacco brands in movies.
"There is a strong correlation over time between how much smoking there is in movies and adult consumption of tobacco," says James Sargent, co-director of Dartmouth Medical School's cancer control program.
What the latest CDC data mean for the fight against smoking is unclear.
"It is encouraging to see that the prevalence rate has finally edged downwards for adults after lingering above 20% for so long," Novotny says. "Nevertheless, we still have 45 million or so smokers in the U.S., and so we still have an enormous challenge to try to reduce this number further."
Fatimah Waseem, USA TODAY