Cigarette smoking and the risk of colorectal cancer in women.
Colorectal cancer incidence rates for smokers, nonsmokers living with smokers (i.e., passive smokers), and nonsmokers in smoke-free households were compared in a 12-year prospective study of 25,369 women who participated in a private census conducted in Washington County, MD, in 1963. Women who smoked had a decreased relative risk of colorectal cancer compared with the risk for nonsmokers (age-adjusted relative risk, 0.76; 95% confidence interval, 0.52-1.10). The risk for passive smokers was similar to that for smokers. The relative risks were significantly reduced for older women; relative risks were 0.42 for smokers and 0.66 for passive smokers over age 65. The data suggest that older women who smoke have a lower risk of colorectal cancer than nonsmokers. The effect may be mediated by an antiestrogenic effect of smoking.
Sandler
R S
RS
Division of Digestive Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7080.
Sandler
D P
DP
Comstock
G W
GW
Helsing
K J
KJ
Shore
D L
DL
D000328:Adult; D000367:Age Factors; D000368:Aged; D015179:Colorectal Neoplasms / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
D014028:Tobacco Smoke Pollution