Table 2 Standardised incidence ratios (SIRs) and their 95% CIs for oesophageal cancer by histology among non‐operated patients with duodenal ulcer, by follow‐up duration, sex, presence of complications and calendar year of index hospitalisation*.

	Adenocarcinoma		Squamous cell carcinoma
	Number of cases	SIR (95% CI)	Number of cases	SIR (95% CI)
Overall	27	1.7 (1.1–2.5)	44	1.3 (0.96–1.8)
Follow‐up duration, years
2–10	17	1.9 (1.1–3.1)	33	1.6 (1.1–2.2)
11+	10	1.5 (0.7–2.8)	11	0.9 (0.5–1.6)
p for trend		0.15		0.01
Sex
Men	23	1.7 (1.1–2.5)	34	1.3 (0.9–1.8)
Women	4	2.1 (0.6–5.5)	10	1.5 (0.7–2.7)
Complication†
Yes	12	1.2 (0.6–2.1)	30	1.4 (0.95–2.0)
No	15	2.6 (1.5–4.3)	14	1.2 (0.6–2.0)
Calendar year of index hospitalisation
1965–79	10	2.1 (1.0–3.8)	18	1.3 (0.8–2.1)
1980–2003	17	1.6 (0.9–2.5)	26	1.3 (0.9–2.0)
Age at entry
<50	6	2.4 (0.9–5.1)	9	2.0 (0.9–3.8)
50–69	15	1.9 (1.1–3.1)	25	1.4 (0.9–2.1)
70–	6	1.2 (0.4–2.5)	10	0.9 (0.4–1.6)
p for trend		0.09		<0.001
Calendar year of follow‐up
1965–94	13	2.3 (1.2–4.0)	25	1.2 (0.8–1.8)
1995–2003	14	1.4 (0.8–2.3)	19	1.5 (0.9–2.3)

*First year of follow‐up was excluded.

†Including bleeding and perforation.