title: Age-period-cohort analysis of smoking prevalence among young adults in Korea.
abstract: OBJECTIVE
  Smoking prevalence among Korean men in their thirties is substantially high (approximately 50%). An in-depth analysis of smoking trends among young adults in their twenties is necessary to devise antismoking policies for the next 10 years. This study aimed to identify the contributions of age, period, and birth cohort effects on smoking prevalence in young adults.
  
  
  METHODS
  Subjects comprised 181,136 adults (83,947 men: 46.3%; 97,189 women: 53.7%) aged 19 to 30 years from the 2008-2013 Korea Community Health Survey. Smoking prevalence adjusted with reference to the 2008 population was applied to the age-period-cohort (APC) model to identify the independent effects of each factor.
  
  
  RESULTS
  For men, smoking prevalence rapidly escalated among subjects aged 19 to 22 years and slowed down among those aged 23 to 30 years, declined during 2008 to 2010 but stabilized during 2011 to 2013, and declined in birth cohorts prior to 1988 but stabilized in subjects born after 1988. However, in APC models, smoking prevalence increased with age in the 1988 to 1991 birth cohort. In this birth cohort, smoking prevalence at age 19 to 20 years was approximately 24% but increased to 40% when the subjects turned 23 to 24 years. For women, smoking prevalence was too low to generate consistent results.
  
  
  CONCLUSIONS
  Over the past six years and in recent birth cohorts, smoking prevalence in adults aged 19 to 30 years has declined and is stable. Smoking prevalence should be more closely followed as it remains susceptible to an increase depending on antismoking policies or social conditions.
authors.affiliation: Graduate School of Public Health, Seoul National University, Seoul, Korea.
authors.forename: Yong Ho
authors.initials: YH
authors.lastname: Jee
authors.affiliation: Graduate School of Public Health, Seoul National University, Seoul, Korea.
authors.forename: Sung-Il
authors.initials: SI
authors.lastname: Cho
mesh_terms: D000328:Adult; D017677:Age Distribution; D015331:Cohort Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012907:Smoking / Q000453:epidemiology*; D055815:Young Adult
keywords: Age; Cigarette smoking; Cohort effect; Period; Prevalence