Abstract P344: Association of Diabetes and Cancer Mortality in American Indians: The Strong Heart Study
Background: Type 2 diabetes has been associated with an increased risk of several cancers, including liver, colon, breast and gastric cancer. These associations, however, have not been well studied in American Indian populations, which experience a high burden of diabetes.
Methods: Prospective cohort study of 4,419 American Indians 45 to 74 years of age followed for up to 20 years. Diabetes was defined by a fasting glucose ≥126 mg/dL or the use of insulin or oral hypoglycemic medication at baseline. Impaired fasting glucose (IFG) was defined as a fasting glucose ≥100 mg/dL and <126 mg/dL without diabetes. Insulin resistance was estimated in non-diabetic participants using the homeostasis model assessment. HbA1c was measured by a high-performance liquid chromatography method. Cancer deaths were assessed by annual mortality surveillance reviews and recorded according to the International Classification of Diseases, 9th Revision.
Results: There were 13.7% participants with IFG and 45.7% with diabetes at baseline. A total of 243 women and 187 men died from cancer during follow-up. After adjusting for age, sex, BMI, education, drinking and smoking status, the fully-adjusted hazard ratios (95% confidence intervals) comparing participants with and without diabetes were 1.19 (0.97-1.45) for overall cancer, 4.09 (1.42-11.79) for gastric cancer, 2.94 (1.17-7.40) for liver cancer and 3.11 (1.22-7.94) for prostate cancer. In flexible dose-response analyses, we found a non-significant dose-response relationship between HbA1C and mortality for gastric, colorectal and liver cancers. Results for HOMA-IR and cancer showed a positive association between HOMA-IR values and liver cancer mortality (4.70 per log unit HOMA-IR (1.55-14.26)). Unexpectedly, we also observed a negative association between HOMA-IR values and prostate cancer mortality (0.25 per log unit HOMA-IR (0.07-0.88)).
Conclusions: In a population with a high burden of diabetes and obesity, and with unique environmental exposures, our data provide additional evidence of heightened risk of cancer mortality associated with diabetes; and confirmation of increased risk of mortality due to stomach and liver cancers.
Author Disclosures: E. García-Esquinas: None. L. Best: None. Y. Jeun-Liang: None. F. Yeh: None. Y. Zhang: None. E. Lee: None. B. Howard: None. J. Farley: None. T. Welty: None. D. Rhoades: None. E. Rhoades: None. J. Umans: None. A. Navas-Acien: None.
- © 2015 by American Heart Association, Inc.