Abstract
林林,陈常中,余晓丹.应用Empower Stats软件分析阈值效应[J].Chinese journal of Epidemiology,2013,34(11):1139-1141
应用Empower Stats软件分析阈值效应
The analysis of threshold effect using Empower Stats software
Received:July 10, 2013  
DOI:10.3760/cma.j.issn.0254-6450.2013.011.021
KeyWord: 阈值效应  分段式回归模型  LRT检验  Bootstrap重抽样
English Key Word: Threshold effect  Segmented regression model  Likelihood ratio test  Bootstrapresampling method
FundProject:
Author NameAffiliationE-mail
LIN Lin Department of Epidemiology,School of Binzhou Medical College, Yantai 264003,China  
CHEN Chang-thong Dana-Farber Cancer Institute, Harvard Medical School, Boston, USA  
YU Xiao-dan Shanghai KeyLaboratory of Children' s Environmental Health, Xinhua Hospital Affliated to School of Medicine,Shanghai Jiaotong University xdyu1108@163.com 
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Abstract:
      生物医学研究中许多研究因素在一定范围内对结果变量无影响或有正效作用,超过某一阈值后,作用大小或/和方向可发生变化,称为阈值效应。在分析研究因素(X)对结果变量(y)的作用有无阈值效应时,可先通过平滑曲线拟合观察是否有分段线性关系,然后采用分段回归模型、LRT检验和Bootstrap重抽样法进行阈值效应分析。美国X & Y Solutions软件公司开发的Empower Stats软件,设有阈值效应分析模块,可输入阈值后按所给阈值分段模拟数据,也可以不输入阈值,由软件自动确定最佳阈值模拟数据,并计算阈值置信区间。
English Abstract:
      In many studies about biomedical research factors influence on the outcomevariable.it has no influence or has a positive effect within a certain range.Exceeding a certainthreshold value,the size of the effect and/or orientation will change,which called threshold effect.Ⅵmether there are threshold effects in the analysis offactors(x)on the outcome variable(Y),it can beobserved through a smooth curve fitting to see whether there iS a piecewise linear relationship.Andthen using segmented regression model.LRT test and Bootstrap resampling method to analyze thethreshold effect.Empower Stats software developed by American X & Y Solutions Inc has a thresholdeffect analysis module.You can input the threshold value at a given threshold segmentation simulateddata.You may not input the threshold,but determined the optimal threshold analog data by thesoftware automatically.and calculated the threshold confidence intervals.
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