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Objective: Inconsistent findings from observational studies have prolonged the controversy over the effects of history of diabetes mellitus (DM) on the risk of esophageal cancer (EC). We conducted a meta-analysis of epidemiologic studies to evaluate the association of a history of DM with the risk of EC., Methods: We identified studies by a literature search of MEDLINE (from 1 January 1966) and EMBASE (from 1 January 1974), through 28 Feburary 2011, and by searching the reference lists of pertinent articles. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were calculated with a random-effects model. All statistical tests were two-sided., Results: A total of 17 studies (6 case-control studies and 11 cohort studies) fulfilled the inclusion and exclusion criteria. Compared with non-diabetic individuals, diabetic individuals had a modestly increased risk of EC (SRRs 1.30, 95% CI: 1.12-1.50), with significant heterogeneity among studies (p = 0.042). In stratified analysis, the SRRs of EC were 1.28 (1.10-1.49) for diabetic men and 1.07 (95% CI, 0.71-1.62) for diabetic women, respectively. In addition, DM was associated with an increased risk of esophageal adenocarcinoma (SRR 2.12, 95% CI 1.01-4.46). There was no significant publication bias (p = 0.127 for Begg's adjusted rank correlation test and p = 0.629 for Egger's regression test)., Conclusion: These findings support the hypothesis that men with diabetes may have a modestly increased risk of EC, while diabetic women were not the case.

Diabetes mellitus (DM) is widely considered to be associated with pancreatic cancer, however, whether DM is a cause or consequence of pancreatic cancer is controversial. In the present study, 1458 patients with pancreatic ductal adenocarcinoma (PDAC) and 1528 age-, sex- and sociodemographic variables-matched controls were recruited in two university-affiliated hospitals from 1st January 2000 to 31st December 2009. DM was defined as fasting blood glucose (FBG) level of 7.0mmol/L or greater. An unconditional multivariable logistic regression analysis was used to estimate adjusted odds ratios (AORs) and 95% confidence interval (CI). Compared with controls, a moderate increased risk of PDAC was observed among cases with long-standing diabetes (⩾2-year duration), with an AOR (95% CI) of 2.11 (1.51–2.94). Interestingly, a significant higher risk was observed among cases with new-onset DM (<2-year duration), with an AOR of 4.43 (3.44–5.72) compared to controls without DM. In addition, we found a synergistic interaction between cigarette smoking and DM on modifying the risk of pancreatic cancer development (AOR=6.17, 95% CI 3.82–9.94). Similarly, a synergistic interaction between new-onset DM and family history of pancreatic cancer was found for pancreatic cancer risk, with an AOR (95% CI) of 11.04 (2.51–48.53). This study suggested that DM could be both an early manifestation of pancreatic cancer and an aetiologic factor. Possible effect modification on DM by family history of pancreatic cancer and smoking status should be further explored in future aetiologic studies. [Copyright &y& Elsevier]