Significantly increased risk of cancer in diabetes mellitus patients: A meta-analysis of epidemiological evidence in Asians and non-Asians

Abstract

Aims/Introduction: Emerging evidence from observational studies suggests that diabetes mellitus affects the cancer risk. However, whether there are differences in the magnitude of the influence of diabetes among ethnic groups is unknown.

Materials and methods: We searched MEDLINE and the Cochrane Library for pertinent articles that had been published as of 4 April 2011, and included them in a meta-analysis of the risk of all-cancer mortality and incidence in diabetic subjects.

Results: A total of 33 studies were included in the meta-analysis, and they provided 156,132 diabetic subjects for the mortality analysis and 993,884 for the incidence analysis. Cancer mortality was approximately 3%, and cancer incidence was approximately 8%. The pooled adjusted risk ratio (RR) of all-cancer mortality was significantly higher than for non-diabetic people (RR 1.32 [CI 1.20-1.45] for Asians; RR 1.16 [CI 1.01-1.34] for non-Asians). Diabetes was also associated with an increased RR of incidence across all cancer types (RR 1.23 [CI 1.09-1.39] for Asians; RR 1.15 [CI 0.94-1.43] for non-Asians). The RR of incident cancer for Asian men was significantly higher than for non-Asian men (P = 0.021).

Conclusions: Diabetes is associated with a higher risk for incident cancer in Asian men than in non-Asian men. In light of the exploding global epidemic of diabetes, particularly in Asia, a modest increase in the cancer risk will translate into a substantial socioeconomic burden. Our current findings underscore the need for clinical attention and better-designed studies of the complex interactions between diabetes and cancer. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00183.x, 2012).

Keywords: Cancer; Diabetes; Meta‐analysis.

Figure 1

Summary of the procedure used to select studies for inclusion in the meta‐analysis.

Figure 2

Adjusted risk ratios (RR) for all‐cancer mortality among the subjects with diabetes. *Cross‐sectional study. Boxes, estimated RR; bars, 95% confidence intervals (CI); diamonds, RR; width of diamonds, pooled CI.

Figure 3

Adjusted risk ratios (RR) for all‐cancer mortality among men and women with diabetes. *Cross‐sectional study. Boxes, estimated RR; bars, 95% confidence intervals (CI); diamonds, RR; width of diamonds, pooled CI. NR, not reported.

Figure 4

Adjusted risk ratios (RR) for all‐cancer incidence among the subjects with diabetes. **Case–control study. Boxes, estimated RR; bars, 95% confidence intervals (CI); diamonds, RR; width of diamonds, pooled CI.

Figure 5

Adjusted risk ratios (RR) for all‐cancer incidence among men and women with diabetes. **Case–control study. Boxes, estimated RR; bars, 95% confidence intervals (CI); diamonds, RR; width of diamonds, pooled CI. NR, not reported.