Patterns of birth cohort-specific smoking histories, 1965-2009

Abstract

Background: Characterizing the smoking patterns for different birth cohorts is essential for evaluating the impact of tobacco control interventions and predicting smoking-related mortality, but the process of estimating birth cohort smoking histories has received limited attention.

Purpose: Smoking history summaries were estimated beginning with the 1890 birth cohort in order to provide fundamental parameters that can be used in studies of cigarette smoking intervention strategies.

Methods: U.S. National Health Interview Surveys conducted from 1965 to 2009 were used to obtain cross-sectional information on current smoking behavior. Surveys that provided additional detail on history for smokers including age at initiation and cessation and smoking intensity were used to construct smoking histories for participants up to the date of survey. After incorporating survival differences by smoking status, age-period-cohort models with constrained natural splines were used to estimate the prevalence of current, former, and never smokers in cohorts beginning in 1890. This approach was then used to obtain yearly estimates of initiation, cessation, and smoking intensity for the age-specific distribution for each birth cohort. These rates were projected forward through 2050 based on recent trends.

Results: This summary of smoking history shows clear trends by gender, cohort, and age over time. If current patterns persist, a slow decline in smoking prevalence is projected from 2010 through 2040.

Conclusions: A novel method of generating smoking histories has been applied to develop smoking histories that can be used in micro-simulation models, and has been incorporated in the National Cancer Institute's Smoking History Generator. These aggregate estimates developed by age, gender, and cohort will provide a complete source of smoking data over time.

Figure 1

Age, period and cohorts used in this analysis. The earliest birth cohort is 1890 and the latest cohort providing cessation data is 1994. Cessation probabilities were assumed to be 0 before age 15 (black dashed line) and initiation probabilities were assumed to be 0 before age 8 (red dashed line). NHIS data are available for ages 18–85 and year 1965–2009 (yellow box). Ages and years with projected estimates from the model are shown in green.

Figure 2

Current smoker prevalence by gender, calendar year, and birth cohort. Dashed lines indicate regions of extrapolation. Interactive Plot: [Males, Females].

Figure 3

Former smoker prevalence by gender, calendar year, and birth cohort. Dashed lines indicate regions of extrapolation. Interactive Plot: [Males, Females].

Figure 4

Annual smoking initiation probabilities by gender, age and birth cohort. Dashed lines indicate regions of extrapolation. Interactive Plot: [Males, Females].

Figure 5

Annual smoking cessation probabilities by gender, age and birth cohort. Dashed lines indicate regions of extrapolation. Interactive Plot: [Males, Females].

Figure 6

Mean cigarettes per day by gender, calendar year, and birth cohort. Dashed lines indicate regions of extrapolation. Interactive Plot: [Males, Females].

Figure 7

Estimates of smoking prevalence (ages 18 years and above, weighted by population from SEER Stat 8.01) by year from 1975 through 2030 compared to unadjusted NHIS results. Interactive Plot: [Male/Female].