Aspirin use, body mass index, physical activity, plasma C-peptide, and colon cancer risk in US health professionals

Am J Epidemiol. 2011 Aug 15;174(4):459-67. doi: 10.1093/aje/kwr115. Epub 2011 Jun 14.

Abstract

Aspirin use decreases colon cancer risk, but this association may vary among population subgroups. The aspirin-colon cancer association was evaluated according to body mass index and physical activity in 1,701 incident colon cancer cases diagnosed during follow-up of 139,310 participants for up to 26 years in 2 US prospective cohort studies that began in 1980 and 1992, respectively. Whether plasma C-peptide levels modified the association was examined by using a nested case-control design (n = 384 cases, 749 controls). Multiplicative and additive interactions were tested. Body mass index did not modify the association; pooled multivariable relative risks for regular aspirin use versus nonuse ranged from 0.74 to 0.75 in the normal weight and obese groups (test for multiplicative interaction, P = 0.75; test for additive interaction, P = 0.66). Pooled multivariable relative risks for regular aspirin use were 0.86 (95% confidence interval (CI): 0.66, 1.11) in the low and 0.67 (95% CI: 0.58, 0.77) in the high physical activity groups with no interaction evident on either the multiplicative or additive scale (P > 0.10). Plasma C-peptide levels also did not modify the aspirin-colon cancer association, with multivariable relative risks of 0.74 (95% CI: 0.50, 1.10) for the low and 0.65 (95% CI: 0.46, 0.92) for the high group. Reductions in colon cancer risk associated with aspirin use were not significantly modified by body mass index, physical activity, or plasma C-peptide level in this study.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Aspirin / administration & dosage*
  • Body Mass Index*
  • C-Peptide / blood*
  • Case-Control Studies
  • Chi-Square Distribution
  • Colonic Neoplasms / blood
  • Colonic Neoplasms / epidemiology*
  • Female
  • Health Personnel*
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Motor Activity*
  • Prospective Studies
  • Risk
  • Surveys and Questionnaires
  • United States / epidemiology

Substances

  • C-Peptide
  • Aspirin