Short-term risk of cancer among women with previous gestational diabetes: a population-based study

• Published in: Diabetic medicine 2016-01, Vol.33 (1), p.39-46
• Main Authors: Bejaimal, S. A. D., Wu, C. F., Lowe, J., Feig, D. S., Shah, B. R., Lipscombe, L. L.
• Format: Article
• Language: English
• Subjects: Adult; Breast Neoplasms - epidemiology; Breast Neoplasms - etiology; Cohort Studies; Diabetes; Diabetes, Gestational - physiopathology; Female; Follow-Up Studies; Humans; Incidence; Kaplan-Meier Estimate; Middle Aged; Ontario - epidemiology; Postpartum Period; Pregnancy; Pregnancy in Diabetics - physiopathology; Premenopause; Registries; Retrospective Studies; Risk Factors; Thyroid Neoplasms - epidemiology; Thyroid Neoplasms - etiology; Universal Coverage; Young Adult
• ISSN: 0742-3071; 1464-5491
• DOI: 10.1111/dme.12796

Aims To evaluate the relationship between gestational diabetes (GDM) and incidence of cancer in women within the first decade postpartum. Methods This population‐based retrospective cohort study compared the risk of cancer in women with GDM with that of a matched control group comprising pregnant women without diabetes. We included women from Ontario, Canada aged 20–50 years with no history of cancer who had given birth between 1995 and 2008 (N = 149 049). Women with GDM (N = 49 684) were matched on age and year of giving birth, in a ratio of 1:2, to pregnant women without diabetes (N = 99 365). Results Over a median 8‐year follow‐up, there were a total of 2927 (1.5%) cancers. After adjustment for covariates, we found no significant difference in overall risk of cancer between women with GDM and matched control subjects; however, GDM was associated with a significantly greater risk of thyroid cancer (adjusted hazard ratio 1.24, 95% CI 1.05, 1.46) and a significantly lower risk of premenopausal breast cancer (hazard ratio 0.86, 95% CI 0.75, 0.98) compared with matched control subjects. Conclusions This large population‐based study did not find a greater risk of cancers among women with GDM during the first decade postpartum; however, GDM was associated with a higher risk of thyroid cancer and a lower risk of premenopausal breast cancer. Further studies are needed to confirm these findings. What's new? This novel study evaluates the relationship between GDM and short‐term incidence of cancer. There is evidence of a relationship between diabetes and cancer, but few studies have examined whether cancer risk is increased in people with early dysglycaemia, such as women with a history of GDM. Using population‐based data, we showed a higher risk of thyroid cancer and lower risk of premenopausal breast cancer in women with GDM compared with matched controls. To our knowledge, this study is the first to document a higher incidence of thyroid cancer in younger women with a history of GDM.