Pattern of 9th- and 10th-grade new smoker trends: 1991-2011

Background: The Youth Risk Behavior Survey (YRBS) has been established to monitor tobacco use trends among adolescents. Thus far, longitudinal analyses linked 9th (or 10th, 11th, 12th separately) graders' prevalence rates across the surveyed years without considering the graders as a cohort.

Purpose: This study aimed to explore the trends of new smokers in the 9th and 10th grade-cohorts separately.

Significance: This is the first study that analyzed adolescents smoking behavior from the perspective of a grade cohort.

Methodology: Based on nationally representative YRBS data, 9th grader's ever smoking prevalence rate is ecologically comparable to 11th grader's rate for 2 subsequent years. The 2-year incidence rate of cigarette smoking among 9th graders to their prospective 11th grade was calculated by subtracting 9th grader's ever smoking rate from the 11th grader's. The 10th grade-cohort was defined in the corresponding manner.

Findings/Results: Instead of looking at one same grade level across the survey years, this study examined the smoking prevalence rates as the grade-cohorts progressed in school. The results showed that the vast majority of grade-cohort ever smoking trends ascended in both sexes separately and combined. In view of new smoker prevalence 1991-2011 trends with or without gender stratification, a two-peak distribution was identified. The lowest new smoker prevalence was found in the 1999 cohorts. The 2-year new smoker prevalence rates went up gradually and reached a peak in 2009.

Conclusions/Recommendations: This study showed an alarmingly ascending national new smoker trends among adolescents. Hence, cohort-specific tobacco prevention and control strategies are suggested.