Diabetes and breast cancer risk: a meta-analysis

Abstract

Background:The potential of an increased risk of breast cancer in women with diabetes has been the subject of a great deal of recent research.Methods:A meta-analysis was undertaken using a random effects model to investigate the association between diabetes and breast cancer risk.Results:Thirty-nine independent risk estimates were available from observational epidemiological studies. The summary relative risk (SRR) for breast cancer in women with diabetes was 1.27 (95% confidence interval (CI), 1.16–1.39) with no evidence of publication bias. Prospective studies showed a lower risk (SRR 1.23 (95% CI, 1.12–1.35)) than retrospective studies (SRR 1.36 (95% CI, 1.13–1.63)). Type 1 diabetes, or diabetes in pre-menopausal women, were not associated with risk of breast cancer (SRR 1.00 (95% CI, 0.74–1.35) and SRR 0.86 (95% CI, 0.66–1.12), respectively). Studies adjusting for body mass index (BMI) showed lower estimates (SRR 1.16 (95% CI, 1.08–1.24)) as compared with those studies that were not adjusted for BMI (SRR 1.33 (95% CI, 1.18–1.51)).Conclusion:The risk of breast cancer in women with type 2 diabetes is increased by 27%, a figure that decreased to 16% after adjustment for BMI. No increased risk was seen for women at pre-menopausal ages or with type 1 diabetes.

A Retrospective Study on the Role of Diabetes and Metformin in Colorectal Cancer Disease Survival

“…Although pancreatic cancer was one of the first cancers to be associated with diabetes, diabetes has also since been associated with colorectal cancer, hepatocellular carcinoma, breast cancer, and bladder cancer, among others [20][21][22][23][24][25] . Many hypotheses have been put forward about the role that diabetes might play in tumour development, including mechanisms arising from hyperinsulinemia, hyperglycemia, and insulin resistance 26 .…”

High glucose and insulin differentially modulates proliferation in MCF-7 and MDA-MB-231 cells

“…It has been reported that up to 16% of older breast cancer patients also suffer from diabetes (Coebergh et al 1999). Many epidemiological studies suggest that women with diabetes have increased risk of breast cancer (Xue & Michels 2007, Suh & Kim 2011, Boyle et al 2012. A recently conducted meta-analysis provides evidence that diabetes is associated with 23% increased risk of breast cancer, especially in post-menopausal women (Liao et al 2011).…”

Effects of Sulfonylureas on Tumor Growth: A Review of the Literature

“…Chlebowski and colleagues showed that breast cancer incidence in postmenopausal diabetic women, compared with nondiabetic women, can be different according to the type of antidiabetic drug; in fact, a 25% risk reduction of breast cancer was reported among women taking metformin versus a 16% increase in risk for women who received other antidiabetics [80]. The main pitfall of this analysis relates to the fact that diabetes seems to confer about a 30% higher risk of breast cancer [81], and this represents a confounding factor when comparing nondiabetic women and diabetic women using metformin. It has become clear that diabetes and breast cancer share some clinical conditions, such as obesity and metabolic syndrome, and this indicates a higher risk when hyperinsulinemia and insulin resistance occur [82].…”