Table 4

Weighted cross-sectional associations between past 30-day tobacco use and Asthma Control Test (ACT) score among adults 18–39 years with asthma at wave 2 of the PATH Study, lower coefficients reflect worse asthma control*

Risk factor at wave 2	N†	US population %	Mean ACT score‡	How tobacco use is modelled
				Model 1 Combustible versus non-combustible tobacco use		Model 2 Specific tobacco products used
				Adjusted coefficient§	95% CI	Adjusted coefficient§	95% CI
Past 30-day tobacco use
Combustible versus non-combustible tobacco use
Never used tobacco	255	28.3	23.6	Ref	Ref	–	–
Formerly used tobacco	463	35.9	23.4	−0.13	−0.56 to 0.29	–	–
Non-combustible use only	47	3.1	22.9¶	−0.40	−1.50 to 0.69	–	–
Any combustible use	655	32.6	22.4	−0.86	−1.32 to –0.39	–	–
Specific tobacco products used
Former
No	957	64.1	22.9	–	–	Ref	Ref
Yes	463	35.9	23.4	–	–	−0.13	−0.53 to 0.27
Cigarette
No	901	74.4	23.5	–	–	Ref	Ref
Yes	519	25.6	22.1	–	–	−1.14	−1.66 to –0.62
Cigar
No	1147	87.1	23.2	–	–	Ref	Ref
Yes	273	12.9	22.5	–	–	−0.08	−0.53 to 0.37
Hookah
No	1272	93.1	23.1	–	–	Ref	Ref
Yes	148	6.9	22.6	–	–	−0.04	−0.66 to 0.59
E-cigarette
No	1233	90.5	23.2	–	–	Ref	Ref
Yes	187	9.5	22.3	–	–	−0.26	−0.88 to 0.36
Smokeless
No	1337	95.6	23.1	–	–	Ref	Ref
Yes	83	4.4	22.9	–	–	0.15	−0.59 to 0.89
Other smoke-related exposures
Cigarette pack-years (per each 5 pack-years)	1420	–	–	−0.09	−0.31 to 0.13	−0.02	−0.23 to 0.19
Past-week SHS exposure (per each 5 hours/week)	1420	–	–	−0.03	−0.09 to 0.02	−0.02	−0.08 to 0.04
Past-month marijuana use**
No	1076	81.2	23.2	Ref	Ref	Ref	Ref
Yes	344	18.8	22.6	−0.07	−0.48 to 0.33	−0.01	−0.41 to 0.40
Relevant medical history
Body mass index
Underweight	41	2.5	23.2¶	0.22	−1.22 to 1.67	0.23	−1.21 to 1.68
Normal	539	36.4	23.3	Ref	Ref	Ref	Ref
Overweight	394	30.2	23.1	0.02	−0.39 to 0.43	0.01	−0.39 to 0.42
Class 1 obese	215	14.8	23.0	−0.19	−0.62 to 0.25	−0.20	−0.63 to 0.24
Class 2+ obese	231	16.1	22.7	−0.35	−0.80 to 0.09	−0.37	−0.81 to 0.07
P12M asthma controller medications††
No	1275	90.3	23.4	Ref	Ref	Ref	Ref
Yes	145	9.7	20.1	−3.26	−4.05 to –2.46	−3.31	−4.09 to –2.52
Sociodemographics
Sex
Female	770	53.0	22.9	Ref	Ref	Ref	Ref
Male	650	47.0	23.3	0.47	0.16 to 0.78	0.44	0.11 to 0.76
Education
No high school degree	165	7.2	22.3	Ref	Ref	Ref	Ref
GED	73	3.9	22.5	0.31	−0.77 to 1.38	0.34	−0.74 to 1.43
High school grad	309	20.3	22.7	0.44	−0.21 to 1.09	0.40	−0.23 to 1.04
Some college	577	39.1	23.1	0.72	0.13 to 1.32	0.70	0.12 to 1.29
≥College graduate	296	29.4	23.7	1.07	0.34 to 1.79	0.99	0.27 to 1.71

Online supplemental table 11 reports SEs for all the weighted estimates presented in this table and adjusted RRs for all the variables in the model.
*N=1420 wave 2 adult (age 18–39) respondents with valid ACT scores, 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.
‡ACT scores can range from 5 to 25. A higher ACT score represents more controlled asthma.
§All (unstandardised) coefficients adjust for the variables in the table plus age, race/ethnicity and lives in an urban area. Bold coefficients are statistically significant at p<0.05.
¶Estimate should be interpreted with caution because it has low statistical precision. It is based on a denominator sample size of less than 50, or the coefficient of variation of the estimate or its complement is larger than 30%.
**Marijuana use variable does not distinguish between combustible and non-combustible use.
††P12M use of asthma controller medication(s).
GED, General Education Development (high school equivalency certificate); PATH, Population Assessment of Tobacco and Health; P12M, past 12-month; RRs, risk ratios; SHS, secondhand smoke.