Hyperinsulinemia Dietary and Lifestyle Scores and Cancer Risk

Abstract

Hyperinsulinemia is a risk factor for several cancers, broadly speaking digestive system cancers and potentially prostate cancer. My colleagues and I developed hyperinsulinemia dietary and lifestyle scores in the Nurses’ Health Study (NHS) to assess the the influence of modifiable components of the insulin on risk of various cancers. To develop the scores, we entered 39 FFQ-derived food groups in stepwise linear regression models and defined indices as patterns most predictive of fasting plasma C-peptide. The two indices were as follows: The empirical dietary index for hyperinsulinemia (EDIH) and the empirical lifestyle index for hyperinsulinemia (ELIH). The validity of the indices was evaluated in two independent samples from Nurses Health Study II and Health Professionals Follow-up Study (HPFS). We then applied the indices longitudinally in NHS and HPFS to study their associations with cancer risk. We found that a highly insulinemic diet or lifestyle was directly associated with digestive system cancer risk, particularly digestive tract cancers and colorectal cancers. This was true in both cohorts and also in the pooled results. We also found that a highly insulinemic diet was directly associated with advanced, lethal and fatal prostate cancer risk. In conclusion, our findings warrant further testing of how reductions in the insulinemic potential of diet can prevent the development of digestive system cancers and certain subtypes of prostate cancer.