Higher serum C-peptide concentrations is associated with increased risk of colorectal cancer (CRC). Therefore, we used diet and C-peptide information from a subsample of women from a large cohort and applied stepwise linear regression to identify food groups that correlated with serum levels of C-peptide. These food contributors then formed dietary patterns for predicting the risk of CRC in the main cohort of women. In up to 22 years of follow-up, we ascertained 985 cases of CRC and 758 colon cancer cases. After adjusting for confounders, we observed that the C-peptide pattern, characterized by higher meat, fish, and sweetened beverage intake, but lower coffee, high fat dairy, and whole grains intake, showed direct association with CRC risk (comparing extreme quintiles, RR=1.35, 95% CI=1.07–1.70. p trend=0.009). In stratified analysis, we did not observe an association between the C-peptide pattern and colon cancer among lean and active women (RR comparing extreme quintiles=0.84, 95% CI=0.50–1.41, p trend=0.23). However, among women who were overweight or sedentary, RR for the same comparison was 1.58 (95% CI=1.20–2.07, p trend=0.002) (p for interaction=0.007). In addition, the association between the C peptide pattern and serum C peptide concentrations is also stronger in the sedentary or overweight group (r=0.23, p<0.0001 vs r=0.15, p=0.01 among lean and active women). In conclusion, we derived a dietary pattern that correlated with C peptide concentrations. This pattern was associated with an increase of colon cancer, especially among women who were at risk for insulin resistance.

Citation Information: Cancer Prev Res 2011;4(10 Suppl):B95.

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2011