Table 1. Distribution of selected demographic variables and risk factors in ESCC cases and controls.

Variable	Cases (n=507)		Controls (n=1, 496)		P a
	n	%	n	%
Age (years)	62.77 (±8.01)		62.77 (±8.84)		0.994
Age (years)					0.225
< 63	271	53.45	753	50.33
≥ 63	236	46.55	743	49.67
Sex					0.406
Male	377	74.36	1,084	72.46
Female	130	25.64	412	27.54
Tobacco use					<0.001
Never	247	48.72	1,090	72.86
Ever	260	51.28	406	27.14
Alcohol use					<0.001
Never	341	67.26	1,329	88.84
Ever	166	32.74	167	11.16
Height (cm)	166.0 (±7.29)		166.1 (±7.08)		0.743
Weight (kg)	61.54 (±9.83)		66.11 (±9.92)		<0.001
BMI (kg/m2)	22.27 (±2.90)		23.91 (±3.03)		<0.001
BMI (kg/m2)					<0.001
< 24	370		779
≥ 24	137		717

^a Two-sided χ² test and student t test; Bold values are statistically significant (P <0.05). BMI: body mass index.