Fasting blood sugar variability linked with cancer risk in patients with type 2 diabetes

Previous studies have shown a consistent increase in cancer among patients with type 2 diabetes mellitus (T2DM). Studies have reported that fasting blood sugar level is independently associated with the risk of cancer onset. Besides fasting blood sugar level alone, fasting blood sugar (FBG) variability may contribute more to increasing cancer onset due to inflammation pathways and oxidative stress.

There is no clarity on the association between long-term changes in FBG and cancer. Prior studies have mainly relied on the relationship between FBG variability and specific site of cancers and have been conducted on populations without diabetes. Also, there is a scarcity of population-based studies on the dose-response relationship between FBG variability and cancer in T2DM patients.

Against the above background, Xiao-rui Cui and colleagues from China aimed to examine the correlation between long-term FBG variability and cancer incidence in patients with type 2 diabetes. They also discussed the interaction of variability in fasting blood sugar with hypertension and FBG-mean with hypertension on cancer risk.

For this purpose, the researchers collected data from 46 761 patients with T2DM aged between 20–80 years who were participants in the Diabetes Standardized Management Program in Shanghai, China. To describe FBG variability, four indicators were adopted, including coefficient of variation (CV), average real variability (ARV), standard deviation (SD), and variation independent of the mean (VIM). The association between long-term fasting blood sugar variability and cancer risk was investigated. The interactive effect of FBG variability was determined with hypertension and FBG-mean with hypertension on the risk of cancer, respectively.

The study led to the following findings:

• Over a median follow-up of 2.86 years, the authors confirmed 2218 cancer cases (51.1% male).
• People in the highest quartile of FBG variability had a raised cancer risk versus those in the lowest quartile.
• The nonlinear association was observed using FBG-VIM, FBG-ARV, and FBG-SD in restricted cubic spline plots.
• The authors observed a significant interaction effect of fasting blood sugar variability with hypertension on cancer, whereas the impact of FBG-mean with hypertension did not attain significance.

The study demonstrated a positive association of fasting blood sugar variability with increased hazards of all-sites cancer. When measurements differ, a nonlinear and linear link was found between FBG variability and cancer.

"The findings imply that long-term changes in FBG variability may be used for identifying T2D patients who are at high risk of cancer and should be targeted for treatment to prevent cancer," the authors wrote. "We found a negative interaction between fasting blood sugar variability and comorbidity of hypertension on cancer risk."

Reference:

The study, "Long-term fasting glucose variability and risk of cancer in patients with type 2 diabetes mellitus: A retrospective population-based cohort study in Shanghai," was published in the Journal of Diabetes.

DOI: https://doi.org/10.1111/1753-0407.13329