Table 1.

Independent variables

Variables	Items	Definition
X1	Age	Years
X2	Hiatal hernia	0 (no)
		1 (yes)
X3	Smoking cigarette	0 (< 1.2 cig./week)
		1 (< 10 cig./day)
		2 (> 10 cig./day)
X4	Alcohol consumption	0 (< once/month)
		1 (once/week)
		2 (> once a week)
X5	GER in upright position	Percentage time
X6	GER in supine position	Percentage time
X7	BAO	mEq/h
X8	MAO	mEq/h
X9	PAO	mEq/h
X10	Gastrin	μg/L