To quantitatively investigate the potential causal associations between Type 2 diabetes mellitus (T2DM) and 17 site-specific cancers, highlighting the significance of this relationship for public health, through a systematic review and meta-analysis of Mendelian randomization studies.
Key Findings:
T2DM significantly increases the risk of pancreatic cancer (OR = 1.09, 95% CI: 1.04-1.15) and endometrial cancer (OR = 1.07, 95% CI: 1.04-1.09).
T2DM is associated with a decreased risk of gastric cancer (OR = 0.90, 95% CI: 0.85-0.93), melanoma (OR = 0.97, 95% CI: 0.95-0.99), and esophageal cancer (OR = 0.86, 95% CI: 0.79-0.93).
No significant causal association was found between T2DM and ten other cancer types.
Interpretation:
The causal relationship between T2DM and cancer is tissue-specific, indicating increased risks for certain cancers and decreased risks for others, which has important implications for targeted prevention strategies.
Limitations:
Potential residual confounding from obesity and dietary patterns may impact the findings.
Limited coverage of cancer types in existing MR studies restricts the generalizability of results.
Variability in effect sizes for thyroid and breast cancers was observed, but these lacked clinical significance.
Conclusion:
T2DM is linked to increased risks of pancreatic and endometrial cancers, while showing negative associations with gastric cancer, melanoma, and esophageal cancer, underscoring the need for tailored public health interventions.
