Introduction:
Young adult smoking initiation and subsequent smoking patterns receive less attention than teenage initiation and patterns, being perceived to be less problematic despite 20-34 year-olds having the highest smoking prevalence of any age group.

Objective:
We set out to establish prevalence of ever-smoking, former, current and daily smoking in 20-year-olds in Ireland, and most common ages of initiation into smoking, and examine motivations for smoking, and reported difficulty with cessation.

Material and Methods:
We use data from 5,190, 20 year-olds from Wave 4 of Cohort ’98 (Child Cohort) of Growing Up in Ireland, a nationally representative longitudinal study of children and young people. All analyses were performed using STATA version 16.1.

Results:
Ever-smoking among 20 year-olds was 74% (n=3,807) and current smoking was 37.5% (n=1,946). Among ever-smoked, 35.5% (n=1,347) were occasional smokers and 15.5% (n=592) were daily smokers. Reported reasons for smoking were “because friends smoke” (29.7%, n=1,082); “enjoy it” (20.9%, n=762); and “helps cope with stress” (15%, n=547). Only 2% (n=74) reported smoking because they “can’t give it up”. However, 12.8% (n=488) said that they had tried to give up cigarettes but found that they couldn’t. More than half of ever-smokers had started smoking between the ages of 17 and 19 (age 17 – 16.4%, n=669; age 18 – 23.1%, n=885; age 19 – 13.6%, n=520).

Conclusions:
Smoking rates are high among 20 year olds with three-quarters of respondents reporting that they had ever-smoked. More than 1 in 8 had tried to stop smoking but were unable to. The ages between 17 and 19 were vulnerable ones for smoking initiation, perhaps indicative of young adults leaving school, starting higher education and jobs, and moving away from home. Of all initiation ages analysed (11-20 years), age 18 was the most frequently reported age suggesting needs for prevention and cessation for older teens and young adults.