Parents who quit smoking and their adult children's smoking cessation: a 20-year follow-up study.

Aims: Extending our earlier findings from a longitudinal cohort study, this study examines parents' early and late smoking cessation as predictors of their young adult children's smoking cessation.

Design: Parents' early smoking cessation status was assessed when their children were aged 8 years; parents' late smoking cessation was assessed when their children were aged 17 years. Young adult children's smoking cessation, of at least 6 months duration, was assessed at age 28 years.

Setting: Forty Washington State school districts.

Participants And Measurements: Participants were 991 at least weekly smokers at age 17 whose parents were ever regular smokers and who also reported their smoking status at age 28. Questionnaire data were gathered on parents and their children (49% female and 91% Caucasian) in a longitudinal cohort (84% retention).

Findings: Among children who smoked daily at age 17, parents' quitting early (i.e. by the time their children were aged 8) was associated with a 1.7 times higher odds of these children quitting by age 28 compared to those whose parents did not quit [odds ratio (OR) 1.70; 95% confidence interval (CI) 1.23, 2.36]. Results were similar among children who smoked weekly at age 17 (OR 1.91; 95% CI 1.41, 2.58). There was a similar, but non-significant, pattern of results among those whose parents quit late.

Conclusions: Supporting our earlier findings, results suggest that parents' early smoking cessation has a long-term influence on their adult children's smoking cessation. Parents who smoke should be encouraged to quit when their children are young.