Association Between Gestational Diabetes Mellitus and Subsequent Risk of Cancer: a Systematic Review of Epidemiological Studies

Purpose: This study aimed at summarizing epidemiological evidence of the association between gestationaldiabetes mellitus (GDM) and subsequent risk of cancer. Materials and
Methods: We searched Medline, Embase,Cancer Lit and CINAHL for epidemiological studies published by February 1, 2014 examining the risk ofcancer in patients with history of GDM using highly inclusive algorithms. Information about first author, yearof publication, country of study, study design, cancer sites, sample sizes, attained age of subjects and methodsused for determining GDM status were extracted by two researchers and Stata version 11.0 was used to performthe meta-analysis and estimate the pooled effects.
Results: A total of 9 articles documented 5 cohort and 4 casecontrolstudies containing 10,630 cancer cases and 14,608 women with a history of GDM were included in thisreview. Taken together, the pooled odds ratio (OR) between GDM and breast cancer risk was 1.01 (0.87-1.17); yetthe same pooled ORs of case-control and cohort studies were 0.87 (0.71-1.06) and 1.25 (1.00-1.56) respectively.There are indications that GDM is strongly associated with higher risk of pancreatic cancer (HR=8.68) andhematologic malignancies (HR=4.53), but no relationships were detected between GDM and other types of cancer.
Conclusions: Although GDM increases the risk of certain types of cancer, these results should be interpretedwith caution becuase of some methodological flaws. The issue merits added investigation and coordinated effortsbetween researchers, antenatal clinics and cancer treatment and registration agencies to help attain betterunderstanding.