Constructing normalcy and discrepancy indexes for birth weight and gestational age using a threshold regression mixture model.
Constructing normalcy and discrepancy indexes for birth weight and gestational age using a threshold regression mixture model.
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使用阈值回归混合模型构建出生体重和胎龄的正常性和差异指数。
DOI：
10.1111/j.1541-0420.2011.01648.x
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发表时间：
2012
期刊：
影响因子：
1.9
通讯作者：
Lee,Mei-LingTing
中科院分区：
文献类型：
--
作者：
Whitmore,GA;Zhang,Guangyu;Lee,Mei-LingTing
出生体重和胎龄是新生儿内在健康的重要指标，在健康研究中既作为结果指标又作为解释变量。这些措施是高度相关的，但偶尔不一致。我们预计，健康研究人员和其他科学家将得到出生体重和胎龄的总结指数的帮助，这些指数可以更准确地指示出生结果是否健康。我们提出了一对指数，我们称之为出生正常指数或BNI和出生差异指数或BDI。这两个指标是出生体重和胎龄的简单函数，并以对数形式通过构造正交。BNI衡量出生体重和胎龄组合是否在正常范围内。BDI衡量出生体重和胎龄是否一致。我们提出了一个BNI的三组分混合模型，其中组分代表早产、高危和健康分娩。BNI分布是从由（2007，Lifetime Data Analysis 13，161-190）提出的胎儿发育的随机模型导出的，并且采用逆高斯分布的混合形式。我们提出了一个非中心分布的BDI模型。BNI和BDI也非常适合比较不同参考人群的出生结果。一个简单的分数和t分数提出了这样的比较。BNI和BDI分布可以使用阈值回归来估计任何感兴趣的参考人群中的出生。
Birth weight and gestational age are important measures of a newborn's intrinsic health, serving both as outcome measures and explanatory variables in health studies. The measures are highly correlated but occasionally inconsistent. We anticipate that health researchers and other scientists would be helped by summary indexes of birth weight and gestational age that give more precise indications of whether the birth outcome is healthy or not. We propose a pair of indexes that we refer to as the birth normalcy index or BNI and birth discrepancy index or BDI. Both indexes are simple functions of birth weight and gestational age and in logarithmic form are orthogonal by construction. The BNI gauges whether the birth weight and gestational age combination are in a normal range. The BDI gauges whether birth weight and gestational age are consistent. We present a three-component mixture model for BNI, with the components representing premature, at-risk, and healthy births. The BNI distribution is derived from a stochastic model of fetal development proposed by (2007,Lifetime Data Analysis13, 161–190) and takes the form of a mixture of inverse Gaussian distributions. We present a noncentralt-distribution as a model for BDI. BNI and BDI are also well suited for making comparisons of birth outcomes in different reference populations. A simplez-score andt-score are proposed for such comparisons. The BNI and BDI distributions can be estimated for births in any reference population of interest using threshold regression.