TY - JOUR
T1 - Cigarette smoking and colorectal cancer
T2 - Long-term, subsite-specific risks in a cohort study of postmenopausal women
AU - Limburg, Paul J.
AU - Vierkant, Robert A.
AU - Cerhan, James R.
AU - Yang, Ping
AU - Lazovich, Deann
AU - Potter, John D.
AU - Sellers, Thomas A.
N1 - Funding Information:
The Iowa Women's Health Study was supported by a grant from the National Cancer Institute (R01 CA39741). Dr. Limburg was supported in part by a National Cancer Institute Career Development Award (K07 CA92216).
PY - 2003/5/1
Y1 - 2003/5/1
N2 - Background & Aims: Cigarette smoking is a putative risk factor for colorectal cancer (CRC). However, long-term CRC risk estimates among female smokers remain limited and inconsistent. The goal of this prospective study was to assess cigarette smoking and CRC risk, overall and by anatomic subsite, among postmenopausal women. Methods: Data were drawn from a large population-based cohort (n = 41,836) of randomly selected women, age 55-69 years at baseline (Iowa Women's Health Study). Cigarette smoking and other CRC risk factors were characterized at baseline (1986). Incident (n = 869) and fatal (n = 249) CRC cases were identified through December 31, 1999. CRC risks were estimated using Cox proportional hazards regression models. Results: Compared with never smokers, ever smokers had slightly increased risks for both incident (relative risk [RR], 1.17; 95% confidence interval [Cl], 1.00-1.36) and fatal (RR, 1.3:1; 95% Cl, 0.98-1.74) CRC in multivariate analyses. Incident CRC risks increased progressively by lengthening induction period (P trend=0.01), reaching a 30% increase (RR, 1.30; 95% Cl, 1.04-1.63) after age 45 years. By anatomic subsite, ever smoked cigarettes and induction period were more strongly associated with incident proximal CRC (P = 0.03 and P trend = 0.03, respectively) than incident distal CRC (P = 0.44 and P trend = 0.10, respectively). Conclusions: In this long-term cohort study of postmenopausal women, cigarette smoking was positively associated with CRC risk. Onset of smoking in the distant past appeared to confer the greatest risk, especially for incident proximal CRC. These data support a potential subsite-specific role for cigarette smoking in colorectal carcinogenesis, at least among women. Based on emerging data, an epigenetic pathway for smoking-induced CRC is proposed.
AB - Background & Aims: Cigarette smoking is a putative risk factor for colorectal cancer (CRC). However, long-term CRC risk estimates among female smokers remain limited and inconsistent. The goal of this prospective study was to assess cigarette smoking and CRC risk, overall and by anatomic subsite, among postmenopausal women. Methods: Data were drawn from a large population-based cohort (n = 41,836) of randomly selected women, age 55-69 years at baseline (Iowa Women's Health Study). Cigarette smoking and other CRC risk factors were characterized at baseline (1986). Incident (n = 869) and fatal (n = 249) CRC cases were identified through December 31, 1999. CRC risks were estimated using Cox proportional hazards regression models. Results: Compared with never smokers, ever smokers had slightly increased risks for both incident (relative risk [RR], 1.17; 95% confidence interval [Cl], 1.00-1.36) and fatal (RR, 1.3:1; 95% Cl, 0.98-1.74) CRC in multivariate analyses. Incident CRC risks increased progressively by lengthening induction period (P trend=0.01), reaching a 30% increase (RR, 1.30; 95% Cl, 1.04-1.63) after age 45 years. By anatomic subsite, ever smoked cigarettes and induction period were more strongly associated with incident proximal CRC (P = 0.03 and P trend = 0.03, respectively) than incident distal CRC (P = 0.44 and P trend = 0.10, respectively). Conclusions: In this long-term cohort study of postmenopausal women, cigarette smoking was positively associated with CRC risk. Onset of smoking in the distant past appeared to confer the greatest risk, especially for incident proximal CRC. These data support a potential subsite-specific role for cigarette smoking in colorectal carcinogenesis, at least among women. Based on emerging data, an epigenetic pathway for smoking-induced CRC is proposed.
UR - http://www.scopus.com/inward/record.url?scp=0141927168&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0141927168&partnerID=8YFLogxK
U2 - 10.1016/S1542-3565(03)70037-8
DO - 10.1016/S1542-3565(03)70037-8
M3 - Article
C2 - 15017492
AN - SCOPUS:0141927168
SN - 1542-3565
VL - 1
SP - 202
EP - 210
JO - Clinical Gastroenterology and Hepatology
JF - Clinical Gastroenterology and Hepatology
IS - 3
ER -