Non-diabetic Glucose levels and Cancer Mortality: A Literature Review

Background: Although diabetes mellitus is a risk factor for cancer, the relationship of an increased glucose concentration at a non-diabetic glucose level with cancer mortality is yet to be determined.

Objective: The aim was to observe whether an increased glucose concentration and/or glucose intolerance at the non-diabetic glucose level can predict cancer mortality.

Methods: Population-based prospective cohort studies evaluating cancer mortality at the non-diabetic level (defined as fasting plasma glucose <7.0 mmol/L and two-hour plasma glucose <11.1mmol/L following an oral glucose tolerance test) were collected via a PubMed search with an additional Google scholar search between 1 January 1966 and 31 July 2016.

Results: We identified seven studies, which met the defined criteria. Studies examining fasting/casual states indicated an increase in cancer mortality with a slight increase in fasting/casual glucose levels in men in particular. Not all, but some studies using a glucose tolerance test indicated an increase in cancer mortality with impaired glucose tolerance/prediabetes. Concerning cause-cancer mortality, glucose intolerance states appeared to have an increase in mortality, particularly due to the stomach, liver and pancreatic cancers.

Conclusion: In these studies reviewed, cancer mortality increased in individuals with an increased glucose concentration and an increased potential was seen in those patients with glucose intolerance even at non-diabetic glucose levels. The outcome of these findings is promising and forms the basis for further studies to directly address the relevance of increased (non-diabetic) glucose and glucose intolerance as a prognostic indicator of cancer mortality.