High GH levels lead to cognitive deficits in children born very preterm
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In children born very preterm, higher levels of growth hormone in early infancy may be partly responsible for cognitive deficits seen in these children at school-age, according to recent findings.
In the study, Peter Anderson, PhD, of Murdoch Childrens Research Institute and Royal Children’s Hospital in Australia, and colleagues evaluated a subgroup of 99 children enrolled in the Victorian Infant Brain Studies (VIBeS) cohort, a prospective, longitudinal study assessing the development of children born very preterm. At the time of delivery, cord blood was taken and blood was subsequently collected and tested for GH concentrations on days 1, 4, 7, 14, 21, 28 and 42. The neonatal GH data were calculated as area under the curve (AUC) summary measures of hormone exposure at 2 and 6 weeks.
At 7 years of age, 83 of the children in the original subgroup were available for follow-up, which included neuropsychological evaluation and brain MRI. The researchers used univariable and multivariable regression modeling where AUC for GH was the primary predictive factor of neurodevelopmental outcomes at 7 years of age.
The researchers found that based on univariable modeling, correlations existed between higher GH levels (2-week AUC) and lower aptitude for tasks related to verbal working memory (P = .04) and shifting attention (P = .01). Multivariate modeling showed similar findings, and 6-week AUC analysis revealed abnormalities in working memory (P = .03), immediate spatial memory (P = .02) and delayed spatial memory (P = .03).
The researchers also found that after adjusting for potential confounders, higher GH levels were associated with larger amygdala volumes (2-week AUC, P = .002; 6-week AUC, P = .03).
“In conclusion, this study was the first of its kind to investigate the relationship between these GH levels and cognitive functioning and brain development at 7 years of age,” the researchers wrote. “Past studies have largely focused on GH deficiency in [small for gestational age] children with limited research available in contemporary cohorts of relatively healthy preterm infants. Findings from the current study suggest that high levels of GH during early infancy may partly explain the well-documented cognitive difficulties these preterm children experience during early school-age. This finding has broader implications, especially with regard to the timing effect of GH.” – by Jennifer Byrne
Disclosure: The researchers report no relevant financial disclosures.