Table 1– Population characteristics in relation to nocturnal gastro-oesophageal reflux (nGOR)

	Never nGOR	Former nGOR	p-value^#	New nGOR	p-value^#	Persistent nGOR	p-value^#
Subjects n	1298	139		201		123
Age at baseline years	33.5±7.2	34.0±6.8	0.45	34.1±6.8	0.23	35.0±7.3	0.03
Male	46.1	46.0	0.99	42.8	0.39	51.2	0.28
Baseline BMI kg·m⁻²	23.3±3.3	23.9±3.3	0.07	24.0±3.4	0.02	25.4±4.4	<0.001
Change in BMI kg·m⁻²	1.9±2.2	1.5±2.4	0.14	2.1±2.1	0.25	2.1±2.7	0.38
Anti-reflux medication^¶	6.7	13.0	0.01	41.9	<0.001	57.9	<0.001
Atopy at baseline	28.8	30.0	0.78	23.9	0.18	30.2	0.75
Smoking			0.05		0.87		0.22
Never	44.2	36.7		47.2		36.1
Ex-smoker	21.6	17.3		20.6		27.9
Quitter	12.9	17.3		12.6		11.5
Smoker	21.3	28.8		19.6		24.6

Data are presented as mean±sd or %, unless otherwise stated. BMI: body mass index. ^#: calculated with “never nGOR” as a reference group; ^¶: any use in the month before follow-up. Bold represents statistical significance.