Cesarean Delivery and Insulin Sensitivity in the Older Adult: The Microbiome and Insulin Longitudinal Evaluation Study

Abstract

The present study was designed to evaluate if mode of delivery at birth is associated with body mass index (BMI) and glucose homeostasis traits in later life, controlling for possible confounders, including maternal history of diabetes. Data were obtained through a racially-diverse, prospective cohort study of non-diabetic, older adults, the Microbiome and Insulin Longitudinal Evaluation Study (MILES). We used generalized linear models to estimate the association between mode of delivery and glycemic status, BMI (kg/m 2), waist circumference (cm), fasting glucose, fasting insulin, insulin secretion, insulin sensitivity and insulin clearance. Further, we estimated the direct and indirect effects of cesarean delivery on glucose and insulin-related traits, as mediated by BMI status. Relative to vaginal delivery, cesarean delivery was associated with a significantly higher BMI (adjusted Beta [aβ]: 3.53 kg/m 2; 95% CI: 0.15, 6.91) and fasting glucose (aβ: 5.12; 95% CI: 0.01, 10.23), a 14% decrease in insulin sensitivity (aβ: -0.14; 95% CI: -0.28, -0.01), and a 58% increased risk (aRR: 1.58; 95% CI: 1.08, 2.31) for prediabetes/diabetes. Associations were mediated in part by BMI, with the strongest evidence observed for glycemic status (proportion mediated 22.6%; p=0.03), fasting insulin (proportion mediated 58.0%; p=0.05) and insulin sensitivity index (proportion mediated 45.9%; p=0.05). Independent of mediation, a significant direct effect of cesarean delivery on glycemic status was observed (aRR: 1.88; 95% CI: 1.16, 2.60). Cesarean delivery may lead to reduced insulin sensitivity and, ultimately, increased risk for developing pre-diabetes and diabetes.

The Skin Microbiome: Current Landscape and Future Opportunities

“…This first contact, alongside pre-programmed mechanisms, is crucial for the development of infant immunity [ 117 ], which preferentially develops tolerance to skin commensals [ 66 , 118 ]. It has been postulated that disruption of native microbial transfer, as observed with C-section, heightens the risk of type 1 diabetes due to links between the microbiota and immune system [ 119 ]. However, metanalyses assessing these risks have found mixed results [ 120 , 121 ].…”