Determinants of insulin concentrations in healthy 1-week-old babies in the community: applications of a bloodspot assay

BACKGROUND: Epidemiological research into insulin secretion and insulin action would be helped by improved ability to measure insulin concentrations in large groups of healthy babies in the neonatal period. Such research is often restricted by the invasive nature of blood sampling. AIMS: We assessed the use of an assay that can measure insulin from bloodspots taken during routine Guthrie testing 7 days after delivery. STUDY DESIGN AND SUBJECTS: Insulin and glucose were measured in 366 seven-day-old infants from heel-prick bloodspots. Time since last feed and type of feed were recorded. RESULTS: Bloodspot insulin concentrations in normal 7-day-old infants were much lower (median (IQR): 15.4 pmol/l (<10-28.5)) than fasting insulin concentrations in adult males (44.3 pmol/l (30.6-72.6)) (p<0.001). Insulin and glucose concentrations were correlated (r=0.33, p