Epidemiological link between obesity, type 2 diabetes mellitus and cancer.

There exists a complex interaction between obesity, type 2 diabetes mellitus (T2DM) and cancer, and an increase in the incidence of cancer is expected with the growing obesity-diabetes pandemic. The association of cancer with diabetes mellitus and obesity appears to be site-specific, the highest risk being for post-menopausal breast cancer, endometrial cancer, and colorectal cancer. Moreover, there is worsening of hyperglycaemia with the onset of cancer, evidencing a bi-directional link between cancer and diabetes mellitus and the need for monitoring for diabetes in cancer survivors. In this review, we look at the epidemiological evidence from observational studies and Mendelian randomization studies linking obesity, diabetes, and cancer, as well as the complex pathophysiological mechanisms involved, including insulin resistance with associated hyperinsulinaemia, the effect of chronic low-grade inflammation, and the effect of various adipokines that are associated with obesity and T2DM. Additionally, we describe the novel therapeutic strategies, based on their role on the discrete pathophysiological mechanisms involved in the tumourigenesis.

Efficacy and Cardiovascular Safety of DPP-4 Inhibitors.

Dipeptidyl peptidase-4 (DPP-4) inhibitors or gliptins belong to the class of incretin mimetics. These drugs have been available on the market for the management of type 2 diabetes mellitus (T2DM) for over a decade. Sitagliptin, linagliptin, vildagliptin, saxagliptin and alogliptin are widely available globally, whilst anagliptin, gemigliptin and teneliptin are used mainly in the Asian countries. The glycemic control conferred by DPP-4 inhibitors varies among individual molecules with an average reduction of glycated hemoglobin (HbA1c) ranging between -0.5 to -1.0% with monotherapy. Additive effects on HbA1c reduction may result from combination therapy with other antidiabetics. Weak evidence from various studies suggests that DPP-4 inhibitors may be useful in treating nonalcoholic fatty liver disease (NAFLD) and polycystic ovary syndrome (PCOS). DPP-4 inhibitors safety is not established in pregnancy, and there is only meagre evidence of its use in T2DM among children. In line with the United States Food and Drug Administration (US FDA) recommendations, sitagliptin, linagliptin, saxagliptin and alogliptin have undergone rigorous cardiovascular outcome trials (CVOTs) in recent years, and the safety data for vildagliptin is available through retrospective analysis of various studies in meta-analysis. Small clinical trial, and meta-analysis based data are available for the CV safety of other DPP-4 inhibitors. In general, the CVOTs and other safety data do not reveal serious warning signals except for saxagliptin (higher risk of hospitalization from heart failure [hHF]), although there is no robust data on the risk of hHF among patients with moderate to severe HF at baseline treated with other DPP-4 inhibitors. This review critically appraises the efficacy and cardiovascular safety of DPP-4 inhibitors to empower clinicians to use this class of antidiabetic medications judiciously.