A meta-analysis comprising 16 studies and 891,426 participants from various regions of the world shows that prediabetes increases the risk of cancer by 15%, with differing risks depending on the type of cancer.
Prediabetes is a general term that refers to an intermediate stage between normoglycaemia and overt diabetes mellitus. It includes individuals with impaired glucose tolerance (IGT), impaired fasting glucose (IFG) or a combination of the two. Results to date from prospective cohort studies investigating the link between prediabetes and risk of cancer are controversial. Thus in this new study, the authors did a meta-analysis to evaluate the risk of cancer in association with the impaired fasting glucose and impaired glucose tolerance population. Of the 16 studies included, four were from Asia, 11 were from the USA and Europe, and one was from Africa.
The researchers found that prediabetes was associated with a 15% increased risk of cancer overall. The results were consistent across cancer endpoint, age, duration of follow-up and ethnicity. There was no significant difference for the risk of cancer with different definitions of prediabetes (IGT or IFG). The authors note that it has been reported that obesity, an important risk factor for diabetes, is also linked to the development of cancer. For this reason, they performed a sensitivity analysis that only included studies that adjusted for BMI in the meta-analysis. They say: "We found that, after controlling for BMI, the presence of prediabetes remained associated with an increased risk of cancer of 22%."