Table 3.

Distribution of Colorectal Cancer Cases and Controls Recruited by the Ontario Familial Colorectal Cancer Registry, Ontario, Canada, during 1997–2001, and Odds Ratio Estimates for Smoking Variables for Males and Females Separately

Variable	Males						Females						Pinteraction
	Casesa		Controlsa		AORb	95% CI	Cases		Controls		AORb	95% CI
	No.	%	No.	%			No.	%	No.	%
Smoking status
Never smoked	140	30	258	36	1.0		347	50	291	51	1.0
Former smoker	250	53	376	52	1.35	1.03, 1.76	244	35	180	32	1.14	0.89, 1.46
Current smoker	82	17	89	12	1.74	1.20, 2.52	103	15	95	17	0.91	0.66, 1.25	0.08
Total no. of years smoked
Never smoked	140	30	258	36	1.0		347	51	291	52	1.0
<15	49	11	97	14	0.97	0.65, 1.46	87	13	66	12	1.09	0.76, 1.56
15–27	113	25	154	22	1.46	1.06, 2.02	89	13	72	13	1.03	0.73, 1.46
>27	158	34	199	28	1.64	1.21, 2.23	154	23	131	23	1.00	0.75, 1.32	0.186
Pack-yearsc smoked
Never smoked	140	32	258	38	1.0		347	54	291	54	1.0
<9	52	12	112	16	0.89	0.60, 1.32	128	20	89	17	1.19	0.87, 1.63
9–22	102	23	141	21	1.50	1.07, 2.10	77	12	68	13	0.95	0.66, 1.37
>22	147	33	171	25	1.76	1.29, 2.40	90	14	91	17	0.82	0.59, 1.14	0.004

Abbreviations: AOR, age-adjusted odds ratio; CI, confidence interval.

^aNumbers may not add up to totals because of missing values (<5% of cases).

^b“Age” defined as age at colorectal cancer diagnosis for cases and referent date (June 30, 1999) for controls.

^cAverage packs per day × number of years smoked.