Table 3– Determinants of change in bronchial reactivity slope according to Phadiatop test result at baseline

Covariate	Phadiatop negative^#		Phadiatop positive^¶
Covariate	Change in bonchial reactivity slope⁺ % (95% CI)	p-value	Change in bonchial reactivity slope⁺ % (95% CI)	p-value
Female sex	-5.6 (-25.5–19.7)	0.634	0.2 (-29.3–42.1)	0.991
Age
Centered at 40 yrs per yr	0.8 (0.1–1.5)	0.023	1.5 (0.3–2.8)	0.012
Centered at 40 yrs² per yr²	0.0^§ (-0.0–0.1)	0.450	0.1^§ (0.0–0.2)	0.009
ETS exposure
Never-smoker	-1.5 (-18.7–19.5)	0.881	2.7 (-24.5–39.7)	0.866
Ever-smoker	11.9 (-12.4–42.8)	0.368	4.7 (-30.7–58.0)	0.828
BMI
Centered at 25 kg·m⁻² per unit	-0.2 (-1.9–1.6)	0.853	-0.5 (-3.3–2.4)	0.731
Change between surveys per unit	3.5 (0.6–6.5)	0.020	0.9 (-3.5–5.4)	0.702
Smoking
Being a smoker at baseline	13.9 (-1.6–31.8)	0.081	39.1 (12.2–72.6)	0.003
Being an ex-smoker at baseline	-6.0 (-21.1–12.0)	0.486	-3.3 (-27.0–28.1)	0.815
Pack-yrs in ever-smokers per 5 yrs	0.8^ƒ (-1.6–3.3)	0.502	6.5^ƒ (3.0–10.2)	<0.001

Bold indicates statistically significant p-values. ETS: environmental tobacco smoke; BMI: body mass index. ^#: n = 2,122. ^¶: n = 883. ⁺: from the baseline value; bronchial reactivity slope is defined as percentage change in forced expiratory volume in 1 s per micromole of methacholine; estimates are expressed in percentage change from baseline slope and adjusted for all other covariates in the table plus concurrent colds at both examinations, seasonal terms, baseline lung function (forced expiratory volume in 1 s, forced vital capacity (FVC) and forced expiratory flow at 25–75% of FVC) and study area. ^§: p = 0.038. ^ƒ: p = 0.044.