History of gestational diabetes in pregnancy increases mortality risk later in life

Key takeaways:

• Crude mortality rate was higher in pregnant women with vs. without history of gestational diabetes.
• A direct association was observed between gestational diabetes and mortality due to CVD.

Women with a history of gestational diabetes had a greater risk for subsequent mortality over 30 years compared with women who have been pregnant without gestational diabetes history, according to cohort study results published in JAMA Internal Medicine.

“Although individuals with a history of gestational diabetes have an almost 10-fold increased risk of developing type 2 diabetes, it remains uncertain whether the association of gestational diabetes with mortality is primarily influenced by the subsequent development of type 2 diabetes and its associated comorbidities and complications,” Yi-Xin Wang, MD, PhD, professor in the department of environmental health at the School of Public Health at Shanghai Jiao Tong University School of Medicine, and the department of nutrition at Harvard T.H. Chan School of Public Health, and colleagues wrote. “It is also uncertain whether different patterns of gestational diabetes, such as recurrence across multiple pregnancies and co-occurrence with other adverse pregnancy or perinatal outcomes, have a similar association with mortality risk.”

Wang and colleagues conducted a cohort study of 91,426 parous women (mean age, 34.9 years) from the U.S. Nurses’ Health Study II who were followed for 30 years from 1989 to 2019. All participants reported at least one pregnancy lasting 6 months or longer at age 18 years or older.

Overall, 3,937 deaths were documented during 2,609,753 person-years of follow-up, with 255 deaths from CVD and 1,397 from cancer, the researchers wrote. Women with a history of gestational diabetes had a higher crude mortality rate compared with women without (1.74 vs. 1.49 per 1,000 person-years). After adjusting for potential confounders and lifestyle factors during the reproductive life span, the risk for mortality stayed higher for women with a history of gestational diabetes (HR = 1.25; 95% CI, 1.11-1.41).

These associations persisted regardless of type 2 diabetes development. In addition, the associations between gestational diabetes history and higher mortality were more robust among women who had gestational diabetes in two or more pregnancies (HR = 1.48; 95% CI, 0.99-2.19), gestational diabetes in the initial and subsequent pregnancies (HR = 1.71; 95% CI, 1.11-2.63) and concurrently reported hypertensive disorders in pregnancy (HR = 1.8; 95% CI, 1.21-2.67), preterm birth (HR = 2.46; 95% CI, 1.66-3.64) or low birth weight (HR = 2.11; 95% CI, 1.21-3.68).

Researchers also observed a direct association between gestational diabetes and the risk for mortality due to CVD (HR = 1.59; 95% CI, 1.03-2.47) in cause-specific mortality analyses. In addition, researchers noted an inverse association between gestational diabetes and cancer mortality (HR = 0.76; 95% CI, 0.59-0.98), but this association was observed only among women who later developed type 2 diabetes.

“The findings emphasize the importance for health care professionals to consider gestational diabetes as a critical factor when evaluating the later-life mortality risk of their patients,” the researchers wrote.