Hack M, Breslau N
Pediatrics. 1986 Feb;77(2):196-202.
To evaluate the role of postnatal growth on IQ at 3 years of age, 139 appropriate for gestational age, very low birth weight infants (less than 1.5 kg) born in 1977 and 1978 were studied at 40 weeks (term), and at 8, 20, and 33 months (corrected) of age. Weight, height, and head circumference were measured at each age, neurologic status was measured at 20 months, and Stanford Binet IQ at 33 months. Multiple regression analysis revealed that head circumference at 8 months of age is the best growth predictor of IQ at 3 years of age. Path analysis was performed to measure the effects of biologic and social factors measured earlier in life on IQ at 3 years. These factors explained 43% of the variance in IQ at 3 years of age. Head circumference at 8 months had a direct effect on IQ at 3 years, controlling for all other variables in the model. Neonatal risk had an indirect effect via head circumference. Neurologic impairment had direct and indirect (via head circumference) effects; race and socioeconomic status had direct effects on IQ but no effects on growth at 8 months of age. Thus, brain growth at 8 months significantly influenced 3 year IQ at 3 years of age among very low birth weight infants, even when medical and sociodemographic variables were controlled.
为评估出生后生长对3岁时智商的作用，对1977年和1978年出生的139名适于胎龄、出生体重极低（小于1.5千克）的婴儿在40周（足月）、8个月、20个月和33个月（矫正年龄）时进行了研究。在每个年龄测量体重、身高和头围，在20个月时测量神经学状态，在33个月时测量斯坦福-比奈智商。多元回归分析显示，8个月时的头围是3岁时智商的最佳生长预测指标。进行了路径分析以测量生命早期所测生物学和社会因素对3岁时智商的影响。这些因素解释了3岁时智商差异的43%。在控制模型中的所有其他变量后，8个月时的头围对3岁时的智商有直接影响。新生儿风险通过头围产生间接影响。神经学损害有直接和间接（通过头围）影响；种族和社会经济地位对智商有直接影响，但对8个月时的生长无影响。因此，即使在控制了医学和社会人口统计学变量后，8个月时的脑生长对极低出生体重婴儿3岁时的智商仍有显著影响。
