title: Prevalence of heavy smoking in California and the United States, 1965-2007.
abstract: BACKGROUND
  The intensity of smoking, not just prevalence, is associated with future health consequences.
  
  
  OBJECTIVE
  To estimate smoking intensity patterns over time and by age within birth cohorts for California and the remaining United States.
  
  
  METHODS
  Two large population-based surveys with state estimates: National Health Interview Surveys, 1965-1994; and Current Population Survey Tobacco Supplements, 1992-2007. There were 139,176 total respondents for California and 1,662,353 for the remaining United States.
  
  
  METHODS
  Number of cigarettes smoked per day (CPD), high-intensity smokers (≥20 CPD); moderate-intensity smokers (10-19 CPD); low-intensity smokers (0-9 CPD).
  
  
  RESULTS
  In 1965, 23.2% of adults in California (95% confidence interval [CI], 19.6%-26.8%) and 22.9% of adults in the remaining United States (95% CI, 22.1%-23.6%) were high-intensity smokers, representing 56% of all smokers. By 2007, this prevalence was 2.6% (95% CI, 0.0%-5.6%) or 23% of smokers in California and 7.2% (95% CI, 6.4%-8.0%) or 40% of smokers in the remaining United States. Among individuals (US residents excluding California) born between 1920-1929, the prevalence of moderate/high-intensity smoking (≥10 CPD) was 40.5% (95% CI, 38.3%-42.7%) in 1965. Moderate/high-intensity smoking declined across successive birth cohorts, and for the 1970-1979 birth cohort, the highest rate of moderate/high-intensity smoking was 9.7% (95% CI, 7.7%-11.7%) in California and 18.3% (95% CI, 16.4%-20.2%) in the remaining United States. There was a marked decline in moderate/high-intensity smoking at older ages in all cohorts, but this was greater in California. By age 35 years, the prevalence of moderate/high-intensity smoking in the 1970-1979 birth cohort was 4.6% (95% CI, 3.0%-6.1%) in California and 13.5% (95% CI, 11.8%-15.1%) in the remaining United States.
  
  
  CONCLUSIONS
  Between 1965 and 2007, the prevalence of high-intensity smoking decreased greatly in the United States. The greater decline in high-intensity smoking prevalence in California was related to reduced smoking initiation and a probable increase in smoking cessation.
authors.affiliation: Cancer Prevention and Control Program, Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA 92093-0901, USA. jppierce@ucsd.edu
authors.forename: John P
authors.initials: JP
authors.lastname: Pierce
authors.forename: Karen
authors.initials: K
authors.lastname: Messer
authors.forename: Martha M
authors.initials: MM
authors.lastname: White
authors.forename: David W
authors.initials: DW
authors.lastname: Cowling
authors.forename: David P
authors.initials: DP
authors.lastname: Thomas
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002140:California / Q000453:epidemiology; D002648:Child; D015331:Cohort Studies; D003625:Data Collection; D006801:Humans; D008875:Middle Aged; D015995:Prevalence; D012907:Smoking / Q000453:epidemiology*; D016540:Smoking Cessation / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology; D055815:Young Adult