Inflammatory Effects of Second Hand Tobacco Smoke and Welding Fume Exposures in Construction Workers

Background: Cardiovascular disease is a leading cause of mortality. While second hand smoke (SHS) exposure is a known contributor, little is known about how SHS combined with other occupational exposures affect cardiovascular health. The objective of this pilot study was to investigate the inflammatory effects of SHS and workplace exposures among construction workers. Methods: We enrolled workers from a local union to participate in a repeated-measures crossover panel study. Workers were monitored daily during three exposure scenarios: no occupational exposures (baseline), exposure to SHS (SHS) and exposure to welding fumes (welding). Blood samples were drawn post-exposure at the same time daily and analyzed for C-reactive protein (CRP) and fibrinogen. Mixed effects regression models were used to examine the differences in inflammatory markers between exposure scenarios. Results: Forty-nine mostly (98%) male, non-smokers (55%) were enrolled for 109 person-days of observation. Across all scenarios, the mean(sd) CRP was lower (p=0.11) among non-smokers 1.9(2.0) mg/L as compared to smokers 2.7(2.7) mg/L. There was no difference (p=0.43) in fibrinogen among non-smokers 277(60) mg/dL as compared to smokers 264(73) mg/dL. Compared to baseline, fibrinogen declined following welding (-23 mg/dL, p=0.05) and SHS (-19 mg/dL, p=0.15) among all participants. Compared to baseline, CRP increased among non-smokers (1.1 mg/L, p=0.08) and decreased among smokers (-1.5 mg/L, p=0.10) following SHS, yet no changes in CRP were observed following welding. Conclusion: Changes in inflammation were observed following welding and SHS exposures. Compared to smokers, non-smokers may be more susceptible to the inflammatory effects of SHS.