The Increased Risk of Colon Cancer Due to Cigarette Smoking May Be Greater in Women than Men

Abstract

Background: Smoking is a recently established risk factor for colon cancer. We wanted to explore the hypothesis that women may be more susceptible to smoking-attributed colon cancer than men as one of the possible explanations for the high colon cancer risk of Norwegian women.Methods: We followed 602,242 participants aged 19 to 67 years at enrollment in 1972-2003, by linkage to national registries through December 2007. We used Cox proportional hazard models to estimate HRs and 95% confidence intervals (CI).Results: During a mean follow-up of 14 years, altogether 3,998 (46% women) subjects developed colon cancer. Female ever-smokers had a 19% (HR ¼ 1.19, 95% CI ¼ 1.09-1.32) and male ever-smokers an 8% (HR ¼ 1.08, CI ¼ 0.97-1.19) increased risk of colon cancer compared with never smokers. For all the four dose-response variables examined, female ever-smokers in the most exposed category of smoking initiation, (HR ¼ 1.48, 95% CI ¼ 1.21-1.81), of daily cigarette consumption (HR ¼ 1.28, 95% CI ¼ 1.06-1.55), of smoking duration (HR ¼ 1.47, 95% CI ¼ 1.11-1.95), and of pack-years of smoking (HR ¼ 1.33, 95% CI ¼ 1.11-1.57) had a significantly increased risk of more than 20% for colon cancer overall and of more than 40% for proximal colon cancer, compared with never smokers. A test for heterogeneity by gender was statistically significant only for ever smoking and risk of proximal colon cancer (Wald c

Smoking increases rectal cancer risk to the same extent in women as in men: results from a Norwegian cohort study

“…In the present report, the association between cigarette smoking and rectal cancer was similar for men and women. Previously, we reported from the same cohort that smoking increased the risk of colon cancer to a greater extent for women than men [2]. Our present findings of no difference between the gender in the smoking related increased risk of rectal cancer are in accordance with three [17-19] smaller Japanese cohort studies including 200 cases of rectal cancer [19] or less [17,18].…”

“…Similarly, stronger relative risk among ever smokers for proximal compared to distal colon cancer has been documented [1]. In our previous study [2], we found that the smoking-related risk of colon cancer was more pronounced in the proximal part of colon for women, but not for men. For the distal part of colon, we could not demonstrate a difference by gender.…”

“…The present study was approved by the Regional Committee for Medical Research Ethics South-East, Norway. More details about the study population are described elsewhere [2,14]. …”

“…In a recently published study based on present cohort, we found that the increased risk of colon cancer due to cigarette smoking may be greater in women than men [2]. …”

Gender and the active smoking and high-sensitivity C-reactive protein relation in late adolescence

“…Given that even with smoking cessation CRP levels remain increased over 19 years ( 31 ), and that CRP levels in childhood predict CRP in adulthood ( 32 ), our novel fi nding of a predominant effect of smoking on hs-CRP levels in girls not using OCs is important in this context. It has been reported that smoking exposure is more harmful to health in women than in men, e.g., female smokers were more vulnerable to colon cancer than male smokers ( 33 ), and smoking in women was associated with 25% greater coronary heart disease risk compared with smoking in men ( 34 ). In line with these reports and the present study, we have previously shown in this adolescent population that long-term passive smoking exposure was associated with lower levels of HDL-cholesterol in 17-year-old girls but not boys ( 35 ).…”