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Research Summary

Should Screening for Colorectal Cancer Start Earlier for Drinkers and Smokers?

Alcohol and tobacco use may increase the risk of colorectal cancer (CRC). It is unknown, however, whether clinicians should initiate CRC screening earlier based on a patient’s history of such use. To explore whether earlier screening is warranted, researchers identified 166,172 cases of CRC through a national medical registry and assessed age at diagnosis. Analyses were controlled for sex, race, and insurance status.

  • CRC was diagnosed significantly earlier in current and past drinkers* than in subjects who never drank.
  • Diagnosis occurred even earlier among current and past drinkers who currently smoked (e.g., 7.8 years earlier in current drinkers who also smoked than in subjects who never drank or smoked).
  • The likelihood of distal CRC was significantly higher among current and past drinkers than in subjects who never drank (odds ratios 1.2 and 1.1, respectively) and among current smokers than in subjects who never smoked (odds ratio 1.2).


This large retrospective study found that CRC was diagnosed in current and past drinkers at a younger age, especially if they currently smoked. While the study helps clarify the association between alcohol, tobacco, and CRC, it neither addressed whether screening could have detected the earlier diagnoses nor accounted for many important confounding factors (e.g., quantity and frequency of drinking and smoking, diet, family history of CRC, obesity, comorbidities that potentially lead to earlier gastrointestinal evaluation). Thus, more investigation is needed to determine whether CRC screening guidelines should be modified according to a patient’s history of alcohol and tobacco use.

Kevin L. Kraemer, MD, MSc
*Current use defined as use in the past year; past use defined as having quit at least 1 year before CRC diagnosis


Zisman AL, Nickolov A, Brand RE, et al. Associations between the age of diagnosis and location of colorectal cancer and the use of alcohol and tobacco: implications for screening. Arch Intern Med. 2006;166(6):629–634.