适用于降低冠心病风险的功能性食品： 运用多变量方法的一种meta-分析
美国临床营养杂志 2005 82: 32-40
背景：由于许多临床研究的结果是相互矛盾的，因此很难确定把适当的生物活性物质用于开发与冠心病有关的新的功能性食品。
目的：这项研究的目的是： 运用名为主成分分析（PCA）的多变量统计学方法，然后通过混合模型处理从meta-分析中获得的数据，meta-分析的目的是同时评估摄取三种类型的生物活性物质（n–3脂肪酸、溶性纤维和植物甾醇）中的一种对于四种生物标记（血浆总胆固醇、甘油三脂、低密度脂蛋白和高密度脂蛋白）中的一种或更多种生物标记的影响。
设计：把从159项研究和副研究中获得的五种主变量（每次研究的患者人数、剂量、年龄、身体质量指数和治疗时间长短）和四种随变量（血液总胆固醇、甘油三脂、低密度脂蛋白和高密度脂蛋白的百分率变化）组成矩阵。把原始数据转变成线性相关单位来组成新的矩阵。
结果：两种主成分足以分别解释主变量和随变量中63.73%和84.27%的变量，植物甾醇和溶性纤维具有降低胆固醇的作用，而n–3脂肪酸可以降低甘油三脂，并升高总胆固醇、低密度脂蛋白和高密度脂蛋白。主成分分析（PCA）和混合模型显示：这种行为与剂量、每次研究的患者人数、年龄和身体质量指数无关，但和治疗时间长短有关。
结论：，主成分分析（PCA）是一项总结关于考察健康所需食品及补充现有的科学信息的有效方法。
关键词：n–3脂肪酸，植物甾醇 溶性纤维 胆固醇 多变量分析 功能性食品
Reference:
Functional foods for coronary heart disease risk reduction: a meta-analysis using a multivariate approach
Am J Clin Nutr 2005 82: 32-40.
Inar A Castro, Lúcia P Barroso and Patricia Sinnecker
Background: It has been difficult to identify the appropriate bioactive substance for the development of new functional foods associated with coronary heart disease, because the results of many clinical studies are contradictory.
Objective: The objective of this study was to use the multivariate statistical approach known as principal component analysis (PCA) followed by a mixed model to process data obtained from a meta-analysis aimed at evaluating simultaneously the effect of ingestion of 1 of 3 types of bioactive substances (n–3 fatty acids, soluble fibers, and phytosterols) on 1 or more of 4 biomarkers (plasma total cholesterol, triacylglycerol, LDL cholesterol, and HDL cholesterol).
Design: Five independent variables (number of patients per study, dose, age, body mass index, and treatment length) and 4 dependent variables (percentage change in blood total cholesterol, LDL, HDL, and triacylglycerol) from 159 studies and substudies were organized into a matrix. The original values were converted to linear correlation units, which resulted in a new matrix.
Results: Two principal components were enough to explain 63.73% and 84.27% of the variance in the independent and dependent variables, respectively. Phytosterols and soluble fibers had a hypocholesterolemic effect, whereas n–3 fatty acids lowered triacylglycerol and increased total, LDL, and HDL cholesterol. The PCA and mixed model showed that this behavior was independent of dose, number of patients per study, age, and body mass index but was associated with treatment length.
Conclusions: PCA is useful for summarizing available scientific information in examinations of health claims for foods and supplements.
Key Words: n–3 Fatty acids • phytosterols • soluble fibers • cholesterol • multivariate analysis • functional foods
