Table 1. Observed counts of aspirin users and non-users, stratified by tumour extent (T), node status (N) and distant metastasis (M) categories, for colorectal, lung, prostate and breast cancer cases (1 July 2006 to 31 December 2009).

	T1	T2	T3	T4	N0	N1	N2	N3	M0	M1
Colorectal
No aspirin	793	1505	5749	1947	5280	2310	2098		6958	2281
		1.0 (ref.)	1.0 (ref.)	1.0 (ref.)		1.0 (ref.)	1.0 (ref.)			1.0 (ref.)
Aspirin	310	633	1929	554	1894	790	599		2527	605
		1.0 (0.8–1.2)	0.8 (0.7–0.9)	0.7 (0.6–0.8)		1.0 (0.9–1.1)	0.9 (0.8–1.0)			0.8 (0.7–0.9)
Lung
No aspirin	677	1308	435	1528	1536	293	1113	921	2014	1894
		1.0 (ref.)	1.0 (ref.)	1.0 (ref.)		1.0 (ref.)	1.0 (ref.)	1.0 (ref.)		1.0 (ref.)
Aspirin	272	507	171	514	589	118	390	324	845	589
		0.8 (0.7–1.0)	0.7 (0.6–0.9)	0.7 (0.6–0.8)		1.1 (0.8–1.4)	0.9 (0.7–1.0)	0.9 (0.8–1.1)		0.8 (0.7–0.9)
Prostate
No aspirin	10 181	6137	3199	553	1191	331			3323	1205
		1.0 (ref.)	1.0 (ref.)	1.0 (ref.)		1.0 (ref.)				1.0 (ref.)
Aspirin	3061	2417	1565	249	342	84			1276	528
		1.1 (1.0–1.1)	1.1 (1.0–1.1)	0.9 (0.7–1.0)		0.8 (0.6–1.1)				0.9 (0.8–1.0)
Breast
No aspirin	7445	4378	748	327	11 000	2850			11 473	333
		1.0 (ref.)	1.0 (ref.)	1.0 (ref.)		1.0 (ref.)				1.0 (ref.)
Aspirin	1048	884	132	77	1657	447			1760	55
		1.0 (0.9–1.1)	0.9 (0.7–1.1)	0.8 (0.6–1.0)		1.0 (0.9–1.1)				0.6 (0.5–0.9)

Abbreviations: CI=confidence interval; OR=odds ratio. Corresponding ORs (with associated 95% CIs) for aspirin vs non-aspirin usage are adjusted for age, gender, education and place of residence.