The Relationship between Obesity and Cancer Mortality in Type 2 Diabetes: A Ten-year Follow-up Study (ZODIAC-21)

Background: Patients with type 2 diabetes mellitus (T2DM) as well as patients with obesity have increased cancer mortality. In a previous paper we suggested that there was a trend for decreased mortality in obese individuals with T2DM. The aim of the new analyses was to investigate the same relationship after increasing our sample size and extending our follow-up period. Patients and Methods: 1353 patients were followed prospectively as part of the ZODIAC study. The cancer mortality rate was evaluated using standardized mortality ratio (SMR) and its association with BMI (kg/m(2)) and obesity (>30 kg/m(2)) with Cox proportional hazard analysis. Results: After a median follow-up time of 9.8 years, 570 patients had died, of whom 122 died front malignancy. The SMR for cancer mortality was 1.47 (95%CI 1.22-1.76). BMI and obesity were not associated with cancer death. Conclusion: The trend towards an inverse relationship between obesity and cancer mortality, as reported previously disappeared after increasing sample size and follow-up to 9.6 years.