Immediate effects of cigar smoking on respiratory mechanics and exhaled biomarkers; differences between young smokers with mild asthma and otherwise healthy young smokers

BACKGROUND We aimed to investigate the immediate respiratory effects of cigar smoking(CS), among young smokers with and without mild asthma. MATERIALS AND METHODS Forty-seven young smokers (18-31years old, 29 males, average pack-years = 3.6 ± 2.8) were enrolled. Twenty-two were mild asthmatics(MA-subgroup) and the remaining 25 were otherwise healthy smokers(HS-subgroup). Exhaled carbon monoxide(eCO), multi-frequency respiratory system impedance(Z), resistance(R), reactance(X), frequency-dependence of resistance(fdr = R5Hz - R20Hz), resonant frequency(fres), reactance area(AX) and exhaled nitric oxide(FENO) were measured at the aforementioned sequence, before and immediately after 30 min of CS, or equal session in the smoking area while using a sham cigar(control group). Chi-square, student's t-tests, mixed linear models and Pearson correlation tests were used for the statistical analysis; level of significance was defined as p < 0.05. RESULTS Immediately after CS, Z5Hz, R5Hz, R10Hz, R20Hz and eCO increased significantly in both subgroups(MA and HS). A greater increase was found for R20 in HS-subgroup. Fdr, fres and AX increased in MA, while decreased in HS. On the contrary, X10 decreased in MA and increased in HS, while X20 showed a greater decrease in MA. Changes in fdr, fres and AX were significantly correlated in both subgroups. No significant FENO alterations were detected in both subgroups. CONCLUSION CS has immediate effects on pulmonary function. Mild asthma predisposes to higher increase of peripheral resistance(increased fdr). In otherwise healthy smokers, central resistance(R20Hz) is more affected. FENO levels are not significantly affected by CS.