Cigarette smoking, but not snuff usage, is associated with a systemic inflammatory profile in young adults

<bold>Background:</bold> Cigarette smoking and nicotine products are associated with systemic inflammation and smoking is a risk factor for developing chronic inflammatory conditions. How snuff usage associates with systemic inflammation is less clear. <bold>Objectives:</bold> Investigate how exposures to cigarette smoking and snuff associate with inflammation-related plasma protein levels in young adults. <bold>Methods:</bold> Ninety-two plasma proteins were measured by the OLINK^TM Target Inflammation panel in 2083 participants (age 21-25 years) from the Swedish population-based cohort BAMSE. Data on cigarette smoking- and snuff habits and exposures, and asthma, were obtained from repeated questionnaires. Data was analysed by adjusted linear regression models. <bold>Results:</bold> Daily smoking was associated with significantly (FDR p-value<0.05) higher levels of 27 proteins and lower levels of two proteins (IL10RA and IL12B) compared to non-smokers. Three proteins (FGF21, MMP10, VEGFA) were higher also in previous and occasional smokers. Daily snuff usage was associated with lower levels of one protein: CSF1. Second-hand smoking at the two latest cohort follow-ups (16 and 24 years) among never smokers was associated with higher levels of several smoking-related proteins (e.g. VEGFA and MMP10). TSLP-levels were higher in smokers with asthma, but not in smokers without asthma or asthmatic non-smokers. <bold>Conclusions:</bold> Daily smoking is associated with a systemic inflammatory profile, while previous and second-hand smoking seem to leave traces of systemic inflammation. Snuff usage was not linked to a inflammatory profile, indicating a primary contribution of inhaled tobacco-related compounds on systemic inflammation.