Diabetes linked to increased blood cancer risk

By Sally Robertson, B.Sc.Jun 11 2012

Patients with Type 2 diabetes are at an increased risk for developing lymphoma, suggest findings from a US study.

The meta-analysis, which included 13 prospective cohort and 13 case‑control studies, showed that diabetes was associated with a 20% increased likelihood for developing non-Hodgkin lymphoma (NHL), leukemia, and myeloma, report Jorge Castillo (The Warren Alpert Medical School of Brown University, Rhode Island, USA) and colleagues.

"DM2 [Type 2 diabetes] has been studied as a potential risk factor for the development of hematologic malignancies; however, studies evaluating such an epidemiologic association have rendered conflicting results," writes the team in Blood.

The analysis comprised cohort studies originating in Europe, America, and Asia and accounted for more than 17,000 cases of Type 2 diabetes and blood cancer.

It showed that the presence of diabetes was associated with an increased risk for non-Hodgkin lymphoma, leukemia, and myeloma, each at an odds ratio of 1.22, but not with Hodgkins lymphoma.

Further analysis of NHL subtypes showed that diabetic individuals were at a significantly higher risk for developing peripheral T-cell lymphoma than nondiabetics, at an odds ratio of 2.42, but were not at any increased risk for diffuse large B-cell lymphoma or follicular lymphoma.

The team says that although the odds of leukemia were increased overall in diabetic patients, they did not identify whether myeloid or lymphoid leukemia drove the association.

"Hyperinsulinemia, hyperglycemia, inflammatory cytokines oversecretion, insulin-like growth factor (IGF) overproduction, and upregulation of IGF-1 receptor are phenomena seen in patients with DM2 that would favor not only malignant transformation of cells but also progression of tumors," write Castillo et al.

However, "DM2 and cancer share common risk factors such as age, gender, overweight, and obesity, waist-to-hip ratio, physical activity, dietary habits, smoking, and alcohol intake, making it difficult to discern the oncogenic effect of each specific risk factor," they note.

Future studies should focus on evaluating the impact of these potential confounders on incidence of hematologic malignancies and specific subtypes by carefully designed multivariate analysis, concludes the team.

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