Evidence of early beta-cell deficiency among children who show impaired fasting glucose: 10-yr cohort study (EarlyBird 56).

Objective: Impaired fasting glucose (IFG) is a predictor of future diabetes and is increasingly common in children, but the extent to which it results from excess insulin demand or failure of supply is unclear. Our aim was to compare the behaviour of insulin sensitivity and beta-cell function in children who developed IFG with those whose glucose levels remained within the normal range.

Methods: We examined trends in fasting glucose, insulin sensitivity (HOMA-S) and beta-cell function (HOMA-B) in 327 healthy children annually from 5 to 15 yr, and the parents at baseline.

Results: Fifty-five children showed IFG, mostly after age 11 yr. Fasting glucose rose progressively and was higher throughout in those who developed IFG compared with those who did not (p < 0.001). Beta-cell function was lower from the age of 5 yr in those who developed IFG (p = 0.006), but there was no difference in BMI (p = 0.71). A difference in insulin sensitivity was revealed on adjustment for covariates (p = 0.03). Glucose was higher (p < 0.001), beta-cell function lower (p = 0.01), and insulin sensitivity the same (p = 0.86) in the mothers of children who showed IFG, compared with those who did not.

Conclusions: IFG is common in contemporary children, and appears to be related to a defect in beta-cell function already present at 5 yr. Similar findings in the mothers of IFG children suggest that the beta-cell defect may be transmissible.