A longitudinal study of serum insulin and glucose levels in relation to colorectal cancer risk among postmenopausal women

Br J Cancer. 2012 Jan 3;106(1):227-32. doi: 10.1038/bjc.2011.512. Epub 2011 Nov 29.


Background: It is unclear whether circulating insulin or glucose levels are associated with increased risk of colorectal cancer. Few prospective studies have examined this question, and only one study had repeated measurements.

Methods: We conducted a prospective study of colorectal cancer risk using the subsample of women in the Women's Health Initiative study whose fasting blood samples, collected at baseline and during follow-up, were analysed for insulin and glucose. Cox proportional hazards models were used to assess associations with colorectal cancer risk in both baseline and time-dependent covariates analyses.

Results: Among 4902 non-diabetic women with baseline fasting serum insulin and glucose values, 81 incident cases of colorectal cancer were identified over 12 years of follow-up. Baseline glucose levels were positively associated with colorectal cancer and colon cancer risk: multivariable-adjusted hazard ratio (HR) comparing the highest (≥99.5 mg dl(-1)) with the lowest tertile (<89.5 mg dl(-1)): 1.74, 95% confidence interval (CI) 0.97-3.15 and 2.25, 95% CI: 1.12-4.51, respectively. Serum insulin and homeostasis model assessment were not associated with risk. Analyses of repeated measurements supported the baseline results.

Conclusion: These data suggest that elevated serum glucose levels may be a risk factor for colorectal cancer in postmenopausal women.

Publication types

  • Multicenter Study

MeSH terms

  • Aged
  • Blood Glucose / analysis*
  • Colorectal Neoplasms / blood*
  • Female
  • Humans
  • Insulin / blood*
  • Longitudinal Studies
  • Middle Aged
  • Postmenopause*
  • Proportional Hazards Models
  • Prospective Studies


  • Blood Glucose
  • Insulin