Abstract 023: The Natural History of Cigarette Smoking From Childhood to Middle-Age: The International Childhood Cardiovascular Cohort (i3C) Consortium

Background: Smoking is known to cause clinical cardiovascular disease. We report the natural history of smoking from childhood until average age 47 years in the large cohort followed in the International Childhood Cardiovascular Cohort (i3C) Consortium, which consists of seven long-standing cohorts in the US, Finland and Australia. Methods: Data on childhood smoking status were obtained from questionnaires answered during age 6-19 during the 1980s. Childhood smoking status was categorized as never smoker, tried smoking only a few times, tried more extensively (including quitters), and regular smoker. The i3C participants had follow-up visits until 2015-18 (Finland 2010-12), when they reported whether they were smokers during their 20s and/or 40s. Results: Of the 9977 participants, prevalence of regular smoking decreased from 35.5% in their 20s, to 20.5% in their 40s; cessation was unrelated to childhood smoking status. As shown in the Figure, among 1816 participants queried at age 18/19, prevalence of regular smoking in their 20s was 4.1% (36/886) in those who never smoked even during adolescence, 12% (22/183) in those who tried only a few times, 21.5% (40/186) in those who tried more extensively, and 76.5% (429/561) in those who were regular smokers during childhood. The pattern was similar among 860 whose last childhood smoking status was queried at age 16/17 (some probably experimented more during the remainder of childhood), but smoking in their 20s was more common for all smoking experimentation groups than in 18/19 year olds. Conclusions: These long-term follow-up data suggest that prevalence of adult smoking was significantly related to level of smoking experimentation during adolescence. However, cessation during adulthood does not depend on childhood smoking status. Policy change (such as taxes and restrictions on smoking indoors) has proven to be one of the most powerful tobacco control tools. These data support an emerging new policy strategy, namely raising the legal cigarette purchase age to 21 years