Prospective cohort study of cigarette smoking and colorectal cancer risk in women

Paul D. Terry, Anthony B. Miller, Thomas E. Rohan

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


Epidemiological studies have consistently found a positive association between cigarette smoking and risk of colorectal adenomas, so the absence of a clear association between smoking and colorectal cancer risk may seem paradoxical. However, if colorectal cancer develops only after an induction period of about 35 years, as has been proposed recently, then studies in which all subjects have fewer than about 35 years between smoking commencement and assessment of outcome would be unlikely to detect this association. Few studies have examined smoking of several decades' duration among women. Therefore, in the cohort study reported here, we used proportional hazards models to estimate hazard ratios relating cigarette smoking to colorectal cancer risk among 89,835 women aged 40-59 years at recruitment into the Canadian National Breast Screening Study, a randomized controlled trial of mammography screening for breast cancer. During an average 10.6 years of follow-up (936,433 person-years), a total of 527 women were diagnosed with incident colorectal cancer (363 colon and 164 rectal). We found that smoking was associated with increased risk of rectal cancer 30 years or more after commencement, and especially with smoking of 40 years' duration or longer (hazard ratio=3.14, 95% Cl=1.33-7.42). There was little evidence for altered risk of colon cancer. These results, along with those of other recent studies, support the hypothesis that tobacco smoking is an initiator, rather than a promoter, of rectal cancer. However, the results do not support an association with colon cancer risk, even with smoking of very long duration and high intensity.

Original languageEnglish (US)
Pages (from-to)480-483
Number of pages4
JournalInternational Journal of Cancer
Issue number3
StatePublished - May 20 2002


  • Cohort studies
  • Colorectal neoplasms
  • Smoking

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


Dive into the research topics of 'Prospective cohort study of cigarette smoking and colorectal cancer risk in women'. Together they form a unique fingerprint.

Cite this