Longitudinal association of exclusive and dual use of cigarettes and cigars with asthma exacerbation among US adults: a cohort study.

Background: Cigar use among adults in the United States has remained relatively stable in the past decade and occupies a growing part of the tobacco marketplace as cigarette use has declined. While studies have established the detrimental respiratory health effects of cigarette use, the effects of cigar use need further characterization. In this study, we evaluate the prospective association between cigar use, with or without cigarettes, and asthma exacerbation.

Methods: We used data from Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health Study to run generalized estimating equation models examining the association between time-varying, one-wave-lagged cigarette and cigar use and self-reported asthma exacerbation among US adults (18+). We defined our exposure as non-established (reference), former, exclusive cigarette, exclusive cigar, and dual use. We defined an asthma exacerbation event as a reported asthma attack in the past 12 months necessitating oral or injected steroid medication or asthma symptoms disrupting sleep at least once a week in the past 30 days. We adjusted for age, sex, race and ethnicity, household income, health insurance, established electronic nicotine delivery systems use, cigarette pack-years, secondhand smoke exposure, obesity, and baseline asthma exacerbation.

Results: Exclusive cigarette use (incidence rate ratio (IRR): 1.26, 95% confidence interval (CI): 1.03-1.54) and dual use (IRR: 1.41, 95% CI: 1.08-1.85) were associated with a higher rate of asthma exacerbation compared to non-established use, while former use (IRR: 1.01, 95% CI: 0.80-1.28) and exclusive cigar use (IRR: 0.70, 95% CI: 0.42-1.17) were not.

Conclusion: We found no association between exclusive cigar use and self-reported asthma exacerbation. However, exclusive cigarette use and dual cigarette and cigar use were associated with higher incidence rates of self-reported asthma exacerbation compared to non-established use. Studies should evaluate strategies to improve cigarette and cigar smoking cessation among adults with asthma who continue to smoke.