Ferguson A Nicole, Grabich Shannon C, Olsen Irene E, Cantrell Rebecca, Clark Reese H, Ballew Wendy N, Chou Jeffrey, Lawson M Louise
Department of Statistics and Analytical Sciences, Kennesaw State University, Kennesaw, GA, USA.
Neonatology. 2018;113(2):108-116. doi: 10.1159/000480118. Epub 2017 Nov 9.
Clinicians have observed preterm infants in the neonatal intensive care unit growing disproportionally; however, the only growth charts that have been available were from preterm infants born in the 1950s which utilized the ponderal index. Prior to creating the recently published BMI curves, we found only 1 reference justifying the use of the ponderal index.
To determine the best measure of body proportionality for assessing growth in US preterm infants.
Using a dataset of 391,681 infants, we determined the body proportionality measure that was most correlated with weight and least correlated with length. We examined the sex-specific overall correlations and then stratified further by gestational age (GA). We then plotted the body proportionality measures versus length to visualize apparent discrepancies in the appropriate measure.
The overall correlations showed weight/length3 (ponderal index) was the best measure but stratification by GA indicated that BMI (weight/length2) was the best measure. This seeming inconsistency was due to negative correlations between ponderal index and length at each GA. BMI, on the other hand, had a correlation with length across GAs, but was uncorrelated with length within GAs. Both ponderal index and BMI were positively correlated with weight.
BMI is the appropriate measure of body proportionality for preterm infants, contrary to current practice.
临床医生观察到新生儿重症监护病房中的早产儿生长比例失调；然而，现有的唯一生长图表来自20世纪50年代出生的早产儿，这些图表使用的是体重指数。在创建最近发布的体重指数曲线之前，我们仅找到1篇参考文献支持使用体重指数。
确定评估美国早产儿生长情况的最佳身体比例测量方法。
利用一个包含391681名婴儿的数据集，我们确定了与体重相关性最高且与身长相关性最低的身体比例测量方法。我们研究了性别特异性总体相关性，然后按胎龄（GA）进一步分层。然后我们绘制身体比例测量值与身长的关系图，以直观显示合适测量方法中的明显差异。
总体相关性显示，体重/身长³（体重指数）是最佳测量方法，但按胎龄分层表明，体重指数（体重/身长²）是最佳测量方法。这种看似不一致的情况是由于每个胎龄下体重指数与身长之间存在负相关。另一方面，体重指数在不同胎龄间与身长相关，但在同一胎龄内与身长不相关。体重指数和体重指数均与体重呈正相关。
与目前的做法相反，体重指数是评估早产儿身体比例的合适测量方法。
