The percentage of adults who smoke a pack of cigarettes a day or more declined from 23.2% in 1965 to 7.6% in 2007, with the decline mostly attributable to fewer young people taking up the habit, study results indicate.
Steeper decreases in pack-a-day smokers were observed among California residents, with rates declining from 22.9% to 2.6% during the same time period, suggesting that the state’s aggressive tobacco control stance has paid off.
“As it now appears that less than 10% of young Californians and less than 20% of young residents in the remaining United States will ever reach these high-intensity levels of cigarette consumption, lung cancer rates should continue to decrease with a continued widening of the difference in rates between California and the remaining United States,” study researcher John Pierce PhD, of the University of California San Diego, and colleagues wrote in the Journal of the American Medical Association.
They analyzed data from National Health Interview Surveys conducted between 1965 and 1994 and the Current Population Survey Tobacco Supplements 1992-2007, totaling 139,176 respondents from California and 1,662,353 for the U.S. overall.
The researchers defined high intensity smoking as ≥20 cigarettes a day, moderate-to-high intensity as ≥10 cigarettes a day, and low-intensity as 0-to-9 cigarettes a day.
The prevalence of high-intensity smokers fell from 56% of all U.S. smokers in 1965 to 40% of all U.S. smokers and just 23% of California smokers in 2007, data indicated.
When the researchers compared smoking trends among different birth cohorts, they found smoking intensity fell with each younger generation. For example, 40.5% of U.S. smokers born between 1920 and 1929 were high-intensity smokers vs. 18.3% born between 1970 and 1979.
And these declines were not accompanied by an increase in low-intensity smoking, the researchers noted. In 1965, low-intensity smoking accounted for 7% of U.S. smokers, a number that fell to 5.3% in 2007.
“As expected, the large decline in the prevalence of pack-a-day smoking has been reflected in declines in lung cancer,” the researchers wrote.
Findings from earlier studies have indicated that U.S. lung cancer deaths peaked at 117 per 100,000 in 1993 and declined to 102 per 100,000 in 2007, with even greater declines observed in California, where rates were lung cancer rates were 109 per 100,000 in 1987 and continuously declined to 77 per 100,000 in the United States.
The researchers offered several explanations for the greater declines in tobacco use and subsequent lung-cancer mortality observed among Californians:
- Early initiation of aggressive cigarette tax programs — California was the first state to raise taxes in 1968 and cigarette prices were higher than the U.S. average during the entire study period.
- Introduction of ongoing, well-funded tobacco control program in 1989.
- Enactment of ordinances restricting workplace cigarette smoking in 1976, replaced by the first statewide smoke-free workplace law in 1994.
“Population norms supporting smoke-free environments in the remaining United States have consistently lagged behind California,” the researchers wrote.
They suggested that future population-wide smoking cessation strategies focus on smoke-free policies that target low-intensity smokers. Further studies should document the way changes in smoking patterns influence tobacco-related health consequences in the United States, according to the researchers.