Size at birth, morning cortisol and cardiometabolic risk markers in healthy Indian children.

Objective: Prenatal programming of the hypothalamic-pituitary-adrenal (HPA) axis may link reduced foetal growth with higher adult chronic disease risk. South Asians have a high prevalence of low birth weight and a thin-fat phenotype, which is associated with subsequent type 2 diabetes and the metabolic syndrome. Altered HPA activity could be one of the pathological processes underlying this link.

Methods: Plasma morning cortisol and corticosteroid-binding globulin (CBG) concentrations were determined in 528 children aged 9·5 years from a prospective birth cohort in India. They had detailed anthropometry at birth, and current measurements of anthropometry, plasma glucose, insulin and lipid concentrations and blood pressure. Insulin resistance (Homeostasis Model Assessment) and insulin secretion (the 30-min insulin increment) were also assessed.

Results: None of the birth measurements were associated with cortisol concentrations, but both birth weight (P = 0·03) and length (P = 0·004) were inversely associated with CBG concentrations. Cortisol concentrations were inversely associated with current body mass index (P = 0·02), and positively associated with glucose (fasting: P < 0·001; 30-min: P = 0·002) concentrations, and systolic blood pressure (P = 0·005), but not insulin resistance or the insulin increment.

Conclusion: Higher morning cortisol is associated with higher cardiometabolic risk markers in Indian children. Although cortisol concentrations did not appear to be related to birth size, small size at birth was associated with higher CBG levels, and may be one of the processes by which foetal undernutrition affects adult health. The findings suggest a need for dynamic testing of HPA axis activity (such as measuring stress responses).