Table 2

Weighted cross-sectional associations between past 30-day tobacco use and lifetime asthma diagnosis at wave 2 of the PATH Study*

Risk factor at wave 2	N†	US population %	Lifetime asthma diagnosis %	Models predicting asthma
				Model 1 Combustible versus non-combustible tobacco use		Model 2 Specific tobacco products used
				Adjusted RR‡	95% CI	Adjusted RR‡	95% CI
Past 30-day tobacco use
Combustible versus non-combustible tobacco use
Never used tobacco	2010	30.5	11.2	Ref	Ref	–	–
Formerly used tobacco	3231	34.0	12.9	1.14	0.94 to 1.38	–	–
Non-combustible use only	392	3.1	12.4	1.09	0.76 to 1.55	–	–
Any combustible use	4634	32.4	12.3	1.02	0.83 to 1.24	–	–
Specific tobacco products used
Former
No	7036	66.0	11.8	–	–	Ref	Ref
Yes	3231	34.0	12.9	–	–	1.14	0.96 to 1.36
Cigarette
No	6559	74.1	12.2	–	–	Ref	Ref
Yes	3708	25.9	12.1	–	–	0.98	0.83 to 1.15
Cigar
No	8622	89.2	11.9	–	–	Ref	Ref
Yes	1645	10.8	14.5	–	–	1.17	1.00 to 1.36
Hookah
No	9283	93.8	12.1	–	–	Ref	Ref
Yes	984	6.2	13.5	–	–	0.99	0.81 to 1.20
E-cigarette
No	8944	90.9	12.1	–	–	Ref	Ref
Yes	1323	9.1	12.7	–	–	0.99	0.83 to 1.19
Smokeless
No	9691	95.7	12.2	–	–	Ref	Ref
Yes	576	4.3	12.5	–	–	1.08	0.84 to 1.40
Other smoke-related exposures
Cigarette pack-years (per each 5 pack-years)	10 267	–	–	0.97	0.89 to 1.06	0.98	0.90 to 1.07
Past-week SHS exposure (per each 5 hours/week)	10 267	–	–	1.01	0.99 to 1.03	1.01	0.99 to 1.03
Past-month marijuana use§
No	8042	84.8	11.7	Ref	Ref	Ref	Ref
Yes	2225	15.2	15.1	1.29	1.10 to 1.50	1.26	1.07 to 1.48
Relevant medical history
Body mass index
Underweight	336	2.8	10.7	0.95	0.65 to 1.39	0.95	0.65 to 1.40
Normal	4292	40.3	11.0	Ref	Ref	Ref	Ref
Overweight	2906	30.3	12.1	1.19	1.01 to 1.40	1.19	1.01 to 1.40
Class 1 obese	1521	14.6	12.5	1.25	1.00 to 1.56	1.25	1.00 to 1.56
Class 2+ obese	1212	12.0	16.4	1.62	1.30 to 2.02	1.62	1.30 to 2.01

Online supplemental table 9 reports SEs for all the weighted estimates presented in this table and adjusted RRs for all the variables in the model.
*N=10 267 wave 2 adult (age 18–39) respondents without chronic obstructive pulmonary disease or other non-asthma respiratory diseases at waves 2–4, with wave 4 PATH Study longitudinal (all waves) weights, and complete data on all analytical variables.
†Unweighted.
‡All RRs adjust for the variables in the table plus age, sex, ethnicity/race, education and lives in an urban area. Bold RRs are statistically significant at p<0.05.
§Marijuana use variable does not distinguish between combustible and non-combustible use.
PATH, Population Assessment of Tobacco and Health; RRs, risk ratios; SHS, secondhand smoke.