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. Author manuscript; available in PMC: 2022 Aug 1.
Published in final edited form as: Lancet Respir Med. 2021 Apr 12;9(8):840–850. doi: 10.1016/S2213-2600(21)00022-9

Figure 2: Biomarkers of tobacco-related exposure.

Figure 2:

(A) Urinary total NNAL over time. (B) Urinary cotinine over time. ENDS=electronic nicotine delivery system. NNAL=4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol. Analyses were unadjusted. Estimates with 95% CI were obtained via back-transformation to the original scale following Box-Cox transformation and multiple imputation. Filled symbols indicate a significant difference relative to week 0 within that group (Bonferroni correction α=0·017; three comparisons with week 0 were done for each group). Six between-group comparisons were done at each timepoint (Bonferroni correction α=0·0083); asterisks indicate a significant difference relative to the cigarette substitute group for that group at that timepoint.