Abstract
VLBW (<1.5gm) contributes disproportionately to developmental handicap and growth failure. To evaluate the role of postnatal brain growth on 3 yr IQ, 139 appropriate for gestational age VLBW born in 1977–78 were studied at 40 wks(term), 8,20 and 33 months corrected age. Growth parameters [weight(Wt),height and head circumference(HC)] were measured at each age, neurologic status at 20 mos and Stanford Binet IQ at 33 mos. Four(3%) VLBW had a subnormal HC (←2SD) at birth, 30(22%) at 40 wks, 19(14%) at 8 mos and 12(9%) persisted at 33 mos of life.
Multiple regression analysis revealed that 8 mos HC is the best growth predictor of 3 yr IQ. Increases in HC above −2SD after 8 mos had no effect on 3 yr IQ. Path Analysis was performed with 4 exogenous variables (race, socioeconomic status (SES), neonatal risk and neurologic impairment), 2 intermediate variables (8 mos Wt, 8 mos HC) and one dependent variable (3 yr IQ). The model explained 43% of the variance in 3 yr IQ. Eight mos Wt did not affect 3 yr IQ, whereas 8 mos HC had a direct effect on 3 yr IQ, controlling for all other variables in the model. Neonatal risk did not directly affect 3 yr IQ but had an indirect effect via HC. Neurologic impairment had direct and indirect (via HC) effects; race and SES had direct effects on IQ but no effects on 8 mos growth (Wt or HC).
Thus normal achievement of brain growth as measured by 8 mos HC is an important predictor of 3 yr IQ among VLBW, even when medical and socio-demographic variables are controlled. Early attention to this important parameter is mandatory.
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Breslau, N., Hack, M. 30 HEAP CIRCUMFERENCE AT 8 MONTHS PREPICTS 3 YEAR IQ IN A10 VERY LOW BIRTHWEIGHT (VLBW) INFANTS. Pediatr Res 19, 115 (1985). https://doi.org/10.1203/00006450-198504000-00060
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DOI: https://doi.org/10.1203/00006450-198504000-00060