Cessation of smoke exposure improves pediatric CF outcomes: Longitudinal analysis of CF Foundation Patient Registry data

•Cessation of smoke exposure reduces the odds of a pulmonary exacerbation by 17% in the first year and by 6% in each additional year of cessation.•Cessation of smoke exposure is associated with 0.7% increase in ppFEV1 in the first year and 0.4% increase in each additional year of cessation.•Cessation of smoke exposure is associated with 1% increase in BMI percentile in the first year and 0.4% increase in each additional year of cessation.•Eliminating smoke exposure may improve CF respiratory and nutritional outcomes and should be prioritized in CF care. Tobacco smoke exposure is a major risk factor for the health of children and adolescents with CF. In this study, we assess whether cessation of smoke exposure is associated with improved outcomes in this population. We used annualized and encounter-based data from the U.S. CF Foundation Patient Registry (2006-2018) on all individuals born 1998-2010. The analytical sample included those who ever reported second-hand smoke exposure (daily or weekly), ever lived with a smoker, or ever reported smoking themselves. We used non-linear mixed models for pulmonary exacerbations and linear mixed models for ppFEV1 and BMI as a function of ceased exposure. The sample included 3,633 individuals contributing 19,629 person-years. Cessation of smoke exposure reduced the odds of a pulmonary exacerbation in 12 months by 17% (OR 0.83, p