Associations between the age at diagnosis and location of colorectal cancer and the use of alcohol and tobacco: implications for screening.
BACKGROUND
Individualizing recommendations for colorectal cancer (CRC) screening intervals and modalities requires accurate risk assessment. Although hereditary predisposition is commonly used, the effect of exogenous risk factors has remained largely unexplored. To address this, we analyzed the age at presentation and location of CRC in relation to alcohol and tobacco use.


METHODS
We queried the IMPAC Medical Registry Services Cancer Information Resource File for CRCs diagnosed between June 1, 1993, and December 31, 2003. Subjects were classified as current, past, or never users of alcohol and tobacco. A logistic regression model for location of CRC and a linear regression model for age at diagnosis were constructed using these explanatory variables along with gender, race, and insurance status.


RESULTS
Our data set consisted of 161 172 patients with CRC. Current drinking, smoking, and smoking plus drinking were associated with younger ages at onset of CRC (adjusted age difference, 5.2, 5.2, and 7.8 years, respectively; P<.001 for all). A distal location of CRC was more likely to occur in current drinkers (odds ratio, 1.192; 95% confidence interval, 1.15-1.23) and smokers (odds ratio, 1.164; 95% confidence interval, 1.12-1.21). Colorectal cancer in men tended to occur earlier (adjusted age difference, 1.9 years; P<.001) and have a distal predominance (odds ratio, 1.42; P<.001) compared with women. The smoking but not the drinking effect size was greater in women than in men (adjusted age difference, 2.6 years; P<.001).


CONCLUSIONS
Alcohol use, tobacco use, and male gender were associated with earlier onset and a distal location of CRC. If confirmed, these factors should guide recommendations regarding initiation of CRC screening and, possibly, choice of techniques.
Zisman
Anna L
AL
Department of Internal Medicine, Evanston-Northwestern Healthcare, Feinberg School of Medicine, Northwestern University, Evanston, IL 60201, USA.
Nickolov
Angel
A
Brand
Randall E
RE
Gorchow
Addi
A
Roy
Hemant K
HK
D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects / Q000453:epidemiology*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D015999:Multivariate Analysis; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology