Table 5.

Prediction of reflux symptoms at age 26 years by history of airway hyperresponsiveness.

				Heartburn		Regurgitation		Heartburn and regurgitation
Challenge agent	Age	n	% with AHR	OR (95% CI)	p	OR (95% CI)	p	OR (95% CI)	p
Methacholine*	9	716	16.9	1.40 (0.81, 2.43)	0.234	1.22 (0.55, 2.73)	0.623	1.51 (0.63, 3.61)	0.354
	11	677	10.8	1.62 (0.84, 3.11)	0.150	1.89 (0.80, 4.48)	0.147	3.00 (1.22, 7.40)	0.017
	13	637	8.3	1.63 (0.76, 3.51)	0.210	1.78 (0.66, 4.82)	0.253	2.92 (1.04, 8.17)	0.041
	15	743	8.3	1.92 (1.00, 3.70)	0.051	2.94 (1.35, 6.42)	0.007	3.86 (1.66, 8.97)	0.002
	21	795	7.7	2.59 (1.38, 4.85)	0.003	4.61 (2.26, 9.40)	<0.001	5.56 (2.53, 12.2)	<0.001
Salbutamol	18	758	7.8	1.01 (0.46, 2.21)	0.978	1.13 (0.39, 3.29)	0.818	1.14 (0.34, 3.85)	0.836

At age 18 years, responsiveness to salbutamol bronchodilator was measured. At ages 9, 11, 13, 15 and 21 years responsiveness to methacholine was measured unless a low FEV₁ precluded methacholine challenge. Airway hyperresponsiveness (AHR) was defined as a PC₂₀ methacholine of 8 mg/mL or less or an increase in FEV₁ of 10% or bronchodilator. OR = odds ratio, 95% CI = 95% confidence intervals. Analyses are by logistic regression using reflux symptoms as the dependent variables and are adjusted for sex.