Prevalence of active and passive smoking among asthma and asthma-associated emergency admissions: a nationwide...

Asthma affects 7% of children and 8% of adults in the United States. There is a paucity of studies examining the association between passive smoking and an increased risk of asthma exacerbations that led the authors to examine the association between various modes of smoking and rates of asthma exacerbations. A retrospective cross-sectional/case-control study was conducted using the National Health and Nutrition Examination Survey dataset (2013-2018). Out of 312,979 respondents, 35,758 (11.43%) had a history of asthma, 9083 (2.9%) had asthma attacks in the past year, and 4731 (1.51%) had asthma-related emergency room admissions in the past year. Prevalence of asthma-related emergency admissions were higher among active cigarette smoking (46.25 vs 35.46%), e-cigarette smoking (26.63 vs 16.07%), and passive smoking at home (37.53 vs 25.67%), workplace passive smoking (14.35 vs 12.11%), in bar (32.38 vs 26.16%), and car (26.21 vs 14.44%) (p < 0.0001). In multivariate regression analysis, we found regular cigarette smoking (OR 1.13, 95% confidence interval (CI) 1.009-1.260, p = 0.0252), e-cigarette (OR 2.13, 95% CI 1.92-2.36, p = 0.0043), cigar use (OR 1.21, 95% CI 1.1-1.33, p < 0.001), ultra-long cigarette length (OR 4.85, 95% CI 3.33-7.06, p < 0.0001), and passive smoking (OR 5.25, 95% CI 3.43-8.06, p < 0.0001) were associated with increased rates of asthma exacerbations over last 12 months. The study shows increased odds of asthma exacerbations among those using ultra-long cigarettes, e-cigarettes, and cigars. Consequently, passive inhalation from even a single smoker in the home, workplace, bars and cars is associated with worsening outcomes in asthma patients.