. Author manuscript; available in PMC: 2014 Feb 1.

Published in final edited form as: J Allergy Clin Immunol. 2013 Feb;131(2):361–368.e11. doi: 10.1016/j.jaci.2012.11.036

Table III.

Asthma age of onset, lung structure and lung function in never smokers

	≤ 18 years n=107	19 to 45 years n=51	> 45 years n=51	P-value
FEV₁ (ml)	−293 (−364 to −221) ^***	−237 (−338 to −137) ^***	−307 (−407 to −207) ^***	< 0.001
Single airway lumen diameter (mm)	−0.35 (−0.62 to −0.08) ^*	−0.28 (−0.64 to 0.08)	−0.77 (−1.14 to −0.40) ^***	< 0.001
Single airway wall thickness (mm)	0.01 (−0.02 to 0.05)	0.02 (−0.02 to 0.07)	−0.03 (−0.08 to 0.02)	0.09
% LAA (%)	−0.68 (−2.83 to 1.47)	3.52 (0.46 to 6.58) ^*	3.44 (0.391 to 6.50) ^*	< 0.001

Results represent the mean difference compared to participants without asthma from linear regression models adjusted for age, sex, height, height2, race/ethnicity, smoking status, pack-years, pipe-years, urine cotinine, household ETS, education, body mass index, waist circumference, occupational exposures, particulate matter exposure. Lung structure models (lumen diameter, wall thickness and %LAA) were additionally adjusted for tube current in milliamperes and CT scanner type. The %LAA model was additionally adjusted for family history of emphysema.

P < 0.001 = *** and P < 0.05 = *.