Neonatal hyperglycemia tied to lower intelligence scores in extremely preterm neonates: BMJ

Approximately 15 million babies are born preterm annually worldwide, indicating a global preterm birth rate of about 11%.Those born extremely preterm (<28 weeks gestation) are at considerable risk of long-term health problems. Itay et al found that magnitude and duration of neonatal hyperglycemia were associated with worse neurodevelopmental outcomes at 6.5 years of age.

Neonatal hyperglycemia which is common in extremely preterm neonates is associated with white matter reduction at term age. So far conflicting reports has been published regarding association between hyperglycemia and later neurological outcomes. To fill the existing knowledge gap, researchers have performed an observational national cohort study(EXPRESS study) at Sweden that included 436 extremely born preterm neonates in the analyses.

Neurodevelopmental outcomes was assessed as follows: Wechsler Intelligence Scale for Children IV(WISC-IV) to measure cognition and Movement Assessment Battery for Children 2(MABC-2) to quantify gross motor and fine motor functioning.

Key findings of the study are:

1. 33.6% of children had moderate to severe neurodevelopmental disability (NDD) at 6.5 years of age.

2. Neonatal hyperglycemia:8mmol/L occurring on two consecutive days had significant association with lower WISC-IV scores at 6.5 years of age.

3. A longer total duration of exposure to hyperglycemia was significantly associated with lower MABC-2 scores.

4. Treatment of hyperglycemia with insulin was not proven to have better neurological outcome.

Authors also observed that for each additional day of hyperglycemia >8mmol/L, there was a decrease in MABC-2 scores by 0.55 points, while for each additional day with blood glucose >14mmol/L there was a decrease in 1.47 points of MABC-2 score.

The possible mechanism of hyperglycemia on brain are oxidative stress, apoptosis and increase in inflammatory cytokines with ensuing microglial activation and astrocytosis subsequently leading to long-term changes in synaptogenesis.

This observational study highlights the potential detrimental long-term effects of neonatal hyperglycemia on motor development and IQ.

Source: BMJ pediatrics