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 2N†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% CIAdjusted coefficient§95% CI
Past 30-day tobacco use
 Combustible versus non-combustible tobacco use
  Never used tobacco25528.323.6RefRef
  Formerly used tobacco46335.923.4−0.13−0.56 to 0.29
  Non-combustible use only473.122.9¶−0.40−1.50 to 0.69
  Any combustible use65532.622.40.86−1.32 to –0.39
 Specific tobacco products used
   Yes46335.923.4−0.13−0.53 to 0.27
   Yes51925.622.11.14−1.66 to –0.62
   Yes27312.922.5−0.08−0.53 to 0.37
   Yes1486.922.6−0.04−0.66 to 0.59
   Yes1879.522.3−0.26−0.88 to 0.36
   Yes834.422.90.15−0.59 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**
  Yes34418.822.6−0.07−0.48 to 0.33−0.01−0.41 to 0.40
Relevant medical history
 Body mass index
  Underweight412.523.2¶0.22−1.22 to 1.670.23−1.21 to 1.68
  Overweight39430.223.10.02−0.39 to 0.430.01−0.39 to 0.42
  Class 1 obese21514.823.0−0.19−0.62 to 0.25−0.20−0.63 to 0.24
  Class 2+ obese23116.122.7−0.35−0.80 to 0.09−0.37−0.81 to 0.07
 P12M asthma controller medications††
  Yes1459.720.13.26−4.05 to –2.463.31−4.09 to –2.52
  Male65047.023.30.470.16 to 0.780.440.11 to 0.76
  No high school degree1657.222.3RefRefRefRef
  GED733.922.50.31−0.77 to 1.380.34−0.74 to 1.43
  High school grad30920.322.70.44−0.21 to 1.090.40−0.23 to 1.04
  Some college57739.123.10.720.13 to 1.320.700.12 to 1.29
  ≥College graduate29629.423.71.070.34 to 1.790.990.27 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.