CHILDHOOD SIZE IS MORE STRONGLY RELATED THAN SIZE AT BIRTH TO GLUCOSEAND INSULIN LEVELS IN 10-11-YEAR-OLD CHILDREN

In adults low birthweight and thinness at birth are associated with in creased risk of glucose intolerance and non-insulin-dependent diabetes mellitus. We have examined the relations between size at birth (birth weight, thinness at birth) and levels of plasma glucose and serum insu lin in children, and compared them with the effects of childhood size. We performed a school-based survey of 10-11-year-old British children (response rate 64%) with measurements made after an overnight fast. O ne group of children (n = 591) was studied fasting while the other (n = 547) was studied 30 min after a standard oral glucose load (1.75 g/k g). Serum insulin was measured by a highly specific ELISA method. Birt h-weight was assessed by maternal recall and thinness at birth using b irth records. Neither fasting nor post-load glucose levels showed any consistent relationship with birthweight or ponderal index at birth. A fter adjustment for childhood height and ponderal index, both fasting and post-load insulin levels fell with increasing birthweight. For eac h kg increase in birthweight, fasting insulin fell by 16.9% (95% confi dence limits 7.1-25.8%, p = 0.001) and post-load insulin by 11.6% (95% confidence limits 3.5-19.1%, p = 0.007). However, the proportional ch ange in insulin level for a 1 SD increase in childhood ponderal index was much greater than that for birthweight (27.2% and -8.8%, respectiv ely, for fasting insulin). We conclude that low birthweight is not rel ated to glucose intolerance at 10-11 years, but may be related to the early development of insulin resistance. However, in contemporary chil dren obesity is a stronger determinant of insulin level and insulin re sistance than size at birth.