Table 1. Intestinal-type NCGA model parameter values.

Parametera	Range Identified Via Model Calibration
Natural history
Gastritis to atrophy	0.0001
Atrophy to intestinal metaplasia	0.0048–0.0200
Intestinal metaplasia to dysplasia	0.0005–0.0010
Dysplasia to preclinical cancer
Age 20–29	0.000000–0.000005
Age 30–39	0.000000–0.000009
Age 40–49	0.000004–0.00003
Age 50–59	0.0002–0.0003
Age 60–69	0.0004–0.0008
Age 70–79	0.0007–0.0018
Age 80–89	0.0011–0.0034
Age 90+	0.0016–0.0066
Preclinical to clinical cancer	0.0410–0.0830
Dysplasia to intestinal metaplasia	0.0051–0.0090
Intestinal metaplasia to atrophy	0.0001–0.0086
Atrophy to gastritis	0.0005–0.0099
Clinical cancer detection
Local	0.006–0.014
Regional	0.024–0.056
Distant	0.034–0.400
Risk factors on disease progression (relative risk)
H. pylori
Gastritis to atrophy	16.1–41.3
Smoking
Atrophy to intestinal metaplasiab
<20 cigarettes per day	1.1–3.7
≥20 cigarettes per day	3.6–17.0
Former smoker	1.1–3.7
Intestinal metaplasia to dysplasiab
<10 cigarettes per day	1.0–2.6
≥10 cigarettes per day	2.1–2.8
Former smoker	1.0–2.6
All other risk factors
Gastritis to atrophyc	0.039–0.098

^aMonthly probabilities unless otherwise noted.

^bRelative to non-smokers (RR = 1).

^cConstant exponential rate (r) of decline per birth cohort as described in the following equation: (1−r)∧t, where t = year of birth − 1901.