Functionally important respiratory symptoms and continued cigarette use versus e-cigarette switching: population assessment of tobacco and health study waves 2-6

Substitution of noncombustible tobacco products for cigarettes could improve respiratory symptoms. We hypothesized that complete cigarette-to-e-cigarette switching would improve respiratory symptoms compared to continued smoking. Longitudinal analysis of data from waves 2–6 (W2–W6; 2014–2021) of the Population Assessment of Tobacco and Health (PATH) Study, an observational cohort study that surveyed 5653 US adults ≥18 years without COPD/chronic bronchitis/emphysema. We compiled 14,947 two-wave (1–2 year) observations with persons who smoked cigarettes at baseline and compared the relation between functionally important respiratory symptoms and switching to exclusive e-cigarette use or quitting tobacco versus continued cigarette use (reference). A 9-point wheezing/nighttime cough index was dichotomized based on index scores of ≥2 or ≥3, previously associated with poorer functional health. Multivariable models assessed how changes in cigarette use predicted worsening/improvement of symptoms. Among those with an index score