Table 3. Adjusted prevalence-odds ratios for having at least one asthma attack in the previous 12 months among a representative cross-sectional sample of adult (≥18 years-old) United States population.

	All Subjects		Never Smokers		Never & Former Smokers
	n = 271,348		n = 153,820		n = 212,537
Acrolein Exposure Quintile [μg/m3]	pOR (95% CI)	p-Value	pOR (95% CI)	p-Value	pOR (95% CI)	p-Value
1st: 1.4E-4 – ≤1.1E-2	Reference		Reference		Reference
2nd: >1.1E-2 – ≤2.1E-2	1.02 (0.94, 1.12)	0.61	1.07 (0.93, 1.22)	0.35	1.03 (0.92, 1.15)	0.60
3rd: >2.1E-2 – ≤3.4E-2	1.02 (0.93, 1.12)	0.69	1.11 (0.97, 1.27)	0.11	1.04 (0.94, 1.16)	0.46
4th: >3.4E-2 – ≤5.5E-2	1.01 (0.92, 1.11)	0.83	0.98 (0.86, 1.12)	0.77	0.97 (0.87, 1.08)	0.60
5th: >5.5E-2 – ≤4.6E-1	1.08 (0.98, 1.19)	0.10	1.13 (0.98, 1.29)	0.08	1.09 (0.98, 1.22)	0.13

Adjusted for sex, age, race/ethnicity, poverty income ratio (imputed five times), education, access to health care, whether a subject's residence was located in an urban or rural area, and NHIS interview year. The unstratified model for all subjects also controlled for smoking status, while the stratified models for never smokers and never & former smokers did not.