Hyperglycaemia is associated with cancer-related but not non-cancer-related deaths: evidence from the IPC cohort

Aims/hypothesis: Hyperglycaemia has been associated with the incidence of all and specific types of cancer, distinct from the risks related to diabetes. The relationships between blood glucose and mortality rates related to all and specific cancers were analysed in comparison with all-cause or non-cancer-related mortality rates in a large, general primary care population in France. Methods: Between January 1991 and December 2008, 301,948 participants (193,221 men and 108,727 women), aged 16–95 years (mean ± SD 44.8 ± 12.0 years for men and 45.1 ± 14.2 years for women), had a health check at the IPC Centre. All data collected in standard conditions during the health checks-up were used for statistical analysis All examinations were performed under fasting conditions and included a blood glucose measurement. Participants with known diabetes (<9%) were excluded from the analysis. Participants were classified into quintiles based on their blood glucose measurement and were followed for a maximum of 17 years (mean ± SD 9.2 ± 4.7 years) to assess all-cause, cancer and non-cancer mortality rates. Results: A non-linear relationship was observed between cancer mortality rates and blood glucose quintile after adjustment for age and sex. There was a significant association between the group with the highest blood glucose level and cancer-related death (multivariate Cox model, HR [95% CI] 1.17 [1.03, 1.34]), while the group with normoglycaemia showed no association with cancer-related deaths. We did not observe a relationship between blood glucose and all-cause or non-cancer mortality rates. An excess risk of death was observed in the highest blood glucose quintile for gastrointestinal cancer and leukaemia. Adjustments for diabetes and aspirin use did not modify the results. However, this excess risk disappeared with use of glucose-lowering agents (HR [95% CI] 1.03 [0.74, 1.43]). Conclusions/interpretation: Hyperglycaemia is associated with significantly higher rates of cancer-related deaths, particularly in gastrointestinal cancer and leukaemia, but not with non-cancer-related deaths. The association is retained when taking into account confounding factors, including chronic aspirin treatment.