S2. Distribution of re-assessment risk level among participants in the control arm (excluding esophageal cancer symptoms in questionnaire-based risk prediction model).

Risk group	Risk level	N	GC	NNS*	P	Sensitivity [% (95% CI)]	aHR (95% CI)
Adjusted for age group (40−49, 50−59, 60−69 years old), sex, ethnicity and marital status (never married, married, divorced and widow); *, The number of participants who should undergo endoscopy screening to identify one incident case; GC, gastric cancer; NNS, number needed to screen; 95% CI, 95% confidence interval; aHR, adjusted hazard ratio.
Low	0	17,481	8	1,240	<0.001	61.82 (47.71−74.28)	Reference
	1	8,552	13
High	≥2	15,586	34	458			2.43 (1.39−4.25)