. Author manuscript; available in PMC: 2015 Feb 25.

Published in final edited form as: Eur Respir J. 2010 Oct 14;37(5):1029–1036. doi: 10.1183/09031936.00081410

TABLE 4.

Interaction tests on cumulative daily average lagged air pollutant^# effects on FeNO^*.

Modifying Factors		PM_2.5	PM₁₀	NO₂	O₃

		Percent Difference (95% CI) ^¶	Percent Difference (95% CI) ^¶	Percent Difference (95% CI) ^¶	Percent Difference (95% CI) ^¶
Asthma	No	18.8 (7.3,31.5) ⁺	9.6 (1.9,17.9) ^§	5.9 (−1.7,14.1)	14.5 (5.3,24.4) ⁺
	Yes	5.8 (−9.1,23.2)	2.1 (−11.4,17.5)	−3.6 (−17.7,12.7)	12.6 (−0.7,27.7) ^f
	P-interaction	0.07	0.27	0.22	0.77
Respiratory Allergy	No	13.9 (1.9,27.4) ^§	7.1 (−1.4,16.4)	4.7 (−1.9,11.7)	12.4 (2.7,23.0) ^§
	Yes	19.6 (7.7,32.9) ⁺	10.8 (2.5,19.9) ^§	7.8 (1.4,14.7) ^§	15.4 (6.0,25.7) ⁺
	P-interaction	0.22	0.32	0.31	0.40
Season	Warm	18.4 (6.8,31.4) ⁺	19.9 (7.9,33.2) ⁺	4.8 (−5.0,15.6)	15.3 (5.3,26.2) ⁺
	Cold	13.0 (−2.6,31.0)	4.3 (−3.9,13.2)	5.4 (−3.4,15.0)	10.2 (−7.5,31.3)
	P-interaction	0.49	0.02	0.92	0.65

All models are adjusted for community, race/ethnicity, sex, asthma, asthma medication use, history of respiratory allergy, age, hour of FeNO collection, BMI, SHS, parent education, language of the questionnaire (English/Spanish), season and whether FeNO testing was conducted outdoors. In addition, stratum specific effects of pollution are reported for each modifying factor (asthma, history of respiratory allergy or season) by including interaction terms wherever appropriate.

All pollutants are 24 hr average, except for ozone (10am–6pm average)

^¶

Results are scaled to the IQR values of 7.5 μg/m³ (PM_2.5), 12.97 μg/m³ (PM₁₀), 10.62 ppb (NO₂) and 15.42 ppb (O₃).

⁺

P<0.01;

^§

P<0.05;

P<0.1