Gestational diabetes and risk of incident primary cancer: a large historical cohort study in Israel

Abstract

Gestational diabetes mellitus (GDM), a state of glucose intolerance associated with pregnancy, is increasing in prevalence. Data regarding the cancer risk associated with GDM are sparse and limited to cancers of the breast and pancreas. This study was conducted to examine the risk of incident overall and site-specific malignancies associated with prior GDM in a historical cohort of women in a large health maintenance organization in Israel. All pregnant women aged 15-50years who underwent 50-g glucose challenge tests between 13 March 1995 and 27 May 2009, without history of malignancy, diabetes, and infertility, were included. Clinical and demographic parameters at index date including age, socioeconomic level, BMI, and parity were collected. Diagnosis of gestational diabetes was based on the 100-g oral glucose tolerance test using Carpenter and Coustan criteria. Cancer diagnoses were obtained from the Israel Cancer Register through linkage data. Among the 185,315 women who had undergone glucose challenge during the study period, 11,264 (6.1%) were diagnosed with GDM. During a total follow-up period of 1.05 million person-years (mean=5.19±3.9, median=4.3), 2,034 incident cases of cancer were identified. GDM was associated with a hazard ratio (HR) of 7.06 (95% CI: 1.69-29.45) for pancreatic cancer (nine cases) and a HR of 1.70 (95% CI: 0.97-2.99) for hematological malignancies (177 cases). The association between GDM and hematological malignancies was limited to women with 5 or more years of follow-up (HR=4.53; 95% CI: 1.81-11.31). GDM is associated with an increased risk of pancreatic cancer and hematologic malignancies.