Association between cigarette smoking, APCmutations and the risk of developing sporadic colorectal adenomas and carcinomas

Table 5 Colorectal cancer, smoking history and APC truncation mutation status.

Smoking Parameters ^a	CRC cases versus controls ^b	APC⁺ versus controls	APC^- versus controls	APC⁺ versus APC^-
Never smoked§
Case/control	30/157	*8/157	*17/157	8/17
Ever smoked
Case/control	58/177	*17/177	*37/177	17/37
OR (95% CI)	1.46 (0.63–3.36)	0.54 (0.09–3.24)	2.31 (0.81–6.60)	0.82 (0.26–2.60)
≤15 cigarettes smoked per day
Case/control	42/137	*13/137	*26/137	13/26
OR (95% CI)	1.32 (0.55–3.16)	0.08 (0.34–3.21)	2.17 (0.74–6.39)	1.00 (0.32–3.15)
> 15 cigarettes smoked per day
Case/control	15/38	*4/38	*10/38	4/10
OR (95% CI)	2.21 (0.67–7.28)	0.74 (0.07–7.94)	3.04 (0.71–13.0)	0.70 (0.14–3.50)
Smoking ≤ 30 years
Case/control	*25/27	*9/123	*16/123	9/16
OR (95% CI)	1.74 (0.65–4.63)	0.07 (0.00–1.11)	1.59 (0.49–5.08)	0.99 (0.26–3.80)
Smoking > 30 years
Case/control	30/52	*8/52	*20/52	8/20
OR (95% CI)	2.86 (1.06–7.7)	2.45 (0.36–16.7)	4.06 (1.20–13.7)	0.77 (0.22–2.68)
Never smoked or starting smoking < 40 years ago§§
Case/control	42/306	*8/306	*28/306	8/28
Starting smoking ≥ 40 years ago
Case/control	45/27	*17/27	*25/27	17/25
OR (95% CI)	1.10 (0.40–3.01)	2.0 (0.34–11.95)	0.93 (0.29–3.01)	2.24 (0.73–6.86)

*Missing values for smoking charactristics gave rise to diminished numbers of CRC cases.
§ Never smoked was used as reference category for "ever smoked", "dosage ≤ 15, > 15" and "duration ≤ 30, > 30".
§§ The combination of never smoked and starting smoking <40 years ago, was used as reference category for "starting smoking ≥ 40 years ago".
^aAll the OR's are adjusted for age and sex.
^bFor overall case-control comparison of CRC status and smoking, all the selected cases from the study population that had completed the questionnaire for smoking parameters were used.

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