Table 2– Determinants of change in bronchial reactivity slope in males and females separately

Covariate	Males^#		Females^¶
Covariate	Change in bonchial reactivity slope⁺ % (95% CI)	p-value	Change in bonchial reactivity slope⁺ % (95% CI)	p-value
Age
Centered at 40 yrs per yr	1.4 (0.5–2.3)	0.003	0.6 (-0.1–1.3)	0.094
Centered at 40 yrs² per yr²	0.0 (0.0–0.1)	0.473	0.1 (0.0–0.1)	0.022
ETS exposure
Never-smoker	-5.2 (-27.0–23.0)	0.686	2.3 (-16.5–25.3)	0.825
Ever-smoker	11.5 (-17.7–51.0)	0.483	8.5 (-16.7–41.4)	0.545
Positive Phadiatop test at baseline	-9.9 (-23.3–5.9)	0.207	-3.2 (-15.4–10.6)	0.629
BMI
Centered at 25 kg·m⁻² per unit	-1.3 (-3.9–1.3)	0.316	0.9 (-0.9–2.8)	0.325
Change between surveys per unit	5.4 (1.1–9.9)	0.012	0.9 (-1.9–3.8)	0.545
Smoking
Being a smoker at baseline	16.7 (-2.9–40.2)	0.100	25.0 (6.6–46.6)	0.006
Being an ex-smoker at baseline	-8.6 (-28.1–16.2)	0.461	-4.0 (-19.2–14.0)	0.641

Bold indicated statistically significant p-values. ETS: environmental tobacco smoke; BMI: body mass index. ^#: n = 1,530. ^¶: n = 1,475. ⁺: 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.