2025-10-15
Fasting hyperglycemia: a silent cancer risk factor?
Endocrinology and Metabolism Oncology
By Ana Espino | Published on october 15, 2025 | 2 min read
#EndocrinologyAndMetabolism #Oncology #PinkOctober #Hyperglycemia
Fasting hyperglycemia (FHG)—defined as elevated blood glucose levels outside of meals—is a common condition, particularly among individuals with type 2 diabetes or metabolic syndrome. Its role in the development of cardiovascular diseases is well established, but its involvement in oncogenesis remains controversial and poorly understood.
Among current esearch limitations is the lack of a robust quantification of the level of evidence linking FHG to specific cancers. Challenges include the complexity of metabolic mechanisms involved, the variability of epidemiological data, and the difficulty in isolating the effect of blood glucose from that of other confounding factors such as body weight, physical activity, and insulin levels.
The main objective of this study was to evaluate the strength of evidence linking exposure to high fasting plasma glucose and the risk of seven major types of cancer, using the “burden of proof” analytical framework developed by the Institute for Health Metrics and Evaluation (IHME).
Hyperglycemia — a driver of cancer?
A total of 96 epidemiological studies, encompassing over 75 million participants worldwide, were included. The relative risk (RR) was estimated for each cancer type based on exposure to FHG, defined as a fasting glucose level above 100 mg/dL (5.6 mmol/L). The seven cancer types analyzed were pancreatic, liver, colorectal, breast, ovarian, endometrial, and lung cancers. The researchers used the Burden of Proof Risk Function (BoPRF) model to evaluate the strength of causal associations.
The analysis revealed a high level of evidence for pancreatic, liver, and endometrial cancers, with a clear dose–response relationship—the higher the fasting glucose level, the greater the risk of developing these cancers.
Colorectal cancer showed an intermediate level of evidence, indicating a plausible but less robust association. Conversely, breast, ovarian, and lung cancers exhibited more heterogeneous or weak results, with inconsistent associations across populations.
Pancreatic cancer stood out, showing a marked increase in relative risk (>1.3) even with moderate rises in fasting glucose, reinforcing the hypothesis of a direct role for hyperglycemia in pancreatic carcinogenesis. Most included studies were well-adjusted cohort analyses, strengthening confidence in the findings, though notable variability remained—likely reflecting contextual or methodological differences between populations.
Too much sugar, too much risk?
Fasting hyperglycemia, often silent and overlooked in the absence of clear symptoms, emerges as a credible risk factor for several metabolically driven cancers. The study aimed to quantify the strength of this association, and its conclusions point to a strong, consistent link between elevated glucose levels and pancreatic, liver, and endometrial cancers. The association with colorectal cancer was moderate, while evidence regarding breast, ovarian, and lung cancers was less convincing.
To deepen understanding, future studies should integrate precise metabolic biomarkers such as HbA1c, insulin levels, and inflammatory cytokines. Establishing multicenter prospective studies with standardized protocols will be essential to confirm and refine these findings. Finally, these results should prompt public health stakeholders to adapt cancer prevention strategies, incorporating hyperglycemia management—even moderate forms—as a lever for cancer risk reduction.
Read next: Breast Cancer: The Role of Lifestyle in Reducing Risk
About the author – Ana Espino
PhD in Immunology, specialized in Virology
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