Associations between biomarkers of nicotine/tobacco exposure and respiratory symptoms among adults who exclusively smoke cigarettes in the U.S.: Findings from the PATH Study Waves 1–4 (2013–2017)

•Biomarkers of tobacco exposure are linked to health outcomes among people who use cigarettes.•The PATH Study provides longitudinal data on biomarkers and tobacco use behavior/outcomes in the US.•Higher acrolein and/or cadmium levels were associated with increased respiratory symptoms among people who smoke cigarettes.