Birth by cesarean section is associated with a higher risk for developing prediabetes and diabetes, according to a new study led by Cedars-Sinai investigators. The findings are published in the Journal of the Endocrine Society.

"Adults reporting birth by C-section, versus those born vaginally, had a 58% increased risk of having prediabetes or diabetes," said Mark O. Goodarzi, MD, PhD, director of Endocrinology and the Endocrine Genetics Laboratory at Cedars-Sinai and principal investigator of the multicenter study. "That group also reported a higher body mass index (BMI), elevated fasting blood sugar levels and decreased insulin sensitivity." 

In the prospective cohort study, investigators analyzed data from North Carolina residents enrolled in the Microbiome and Insulin Longitudinal Evaluation Study (MILES). Since 2018, health information from participating Black and non-Hispanic white adults between 40 and 80 years of age has been collected with the goal of assessing the role the gut microbiome may have in insulin homeostasis and the development of Type 2 diabetes. 

Previous studies have suggested that babies born via cesarean section, through the wall of the mother’s abdomen, have a different microbiome composition than those who come through the birth canal. 

“While we did not assess the microbiome in this study, alterations in gut bacteria could explain our findings. To isolate the effect of C-section on the risk for developing diabetes or prediabetes in adulthood, we accounted for genetic factors, the maternal history of diabetes and hypertension, and the shared lifestyle of both mother and child with diabetes,” said Goodarzi, who holds the Eris M. Field Chair in Diabetes Research.

Investigators note one limitation of the study is that the mode of delivery and maternal history of diabetes were self-reported.

"Although the cesarean group was small, the direct and indirect associations did still hold," said Roma Gianchandani, MD, medical director of Diabetes Quality and vice chair of Quality and Innovation at Cedars-Sinai. "This data calls for larger studies from health system databases or longitudinal observations. In the interim, this data makes a case for early evaluation of patients born via C-section for metabolic derangements, as early lifestyle interventions could be impactful." 

Goodarzi says the next step in data analysis from the MILES cohort is a closer look at the microbiomes of the adults born through different modes of delivery.

"We want to compare the microbiome in those born via C-section to those born vaginally. We can attempt to identify gut bacteria associated with higher BMI, increased fasting glucose, reduced insulin sensitivity, and a higher risk of prediabetes and diabetes in those born via C-section," said Goodarzi.

According to the Centers for Disease Control and Prevention, 37 million people in the U.S. have diabetes and another 96 million people are estimated to be prediabetic.

Investigators from Harbor-UCLA Medical Center, Wake Forest University School of Medicine, Baylor College of Medicine and the University of Virginia School of Medicine also contributed to the study.

Funding: This research was supported by the National Institute of Diabetes and Digestive and Kidney Diseases (R01DK10958801).