Lavoué J, Bégin D, Beaudry C, Gérin M
Groupe de recherche interdisciplinaire en santé (GRIS), Département de santé environnementale et santé au travail, Faculté de médecine, Université de Montréal PO Box 6128, Main Station, Montreal, QC, Canada H3C 3J7.
Ann Occup Hyg. 2007 Mar;51(2):161-72. doi: 10.1093/annhyg/mel068. Epub 2006 Oct 17.
This study presents a procedure allowing the numerical synthesis of exposure data reported in different ways in the literature, including summary parameters and single measurements. The procedure was applied to literature regarding formaldehyde exposure in the reconstituted wood panels industry, including oriented-strand board (OSB), medium density fibre board (MDF) and particle board (PB).
For each publication providing summary parameters we estimated geometric means (GM) and geometric standard deviations (GSD) by assuming lognormality of exposure levels. Monte Carlo simulation was performed to re-create datasets from the sample sizes and estimated GMs and GSDs, allowing their subsequent formatting together with the single measurements. The precision and bias of the methods used to estimate GMs and GSDs were evaluated.
Altogether, the 13 articles included in our study yielded a final database of 874 data, of which 732 were simulated. For both area and personal data, exposures corresponding to MDF and PB were similar while OSB levels were lower. The most recent available personal levels (1985-1994) were highest in PB for jobs performed in the vicinity of the press (GM=0.63 mg m-3). Corresponding area levels were highest for PB in the main production zone (GM=0.43 mg m-3). Mixed-effects models fitted to area PB data explained 38% of the total variability. A 6-fold decrease in exposures from 1965 to 1995 was estimated. Replication of the simulation process yielded relative standard deviations of the calculated GMs and GSDs between 10 and 20%. The relative biases of the methods used to estimate GMs and GSDs varied across methods and decreased with higher sample sizes (from approximately 15% for n=5 to less than 5% for n=30, in absolute value). The precision also varied across methods and improved with higher sample sizes (from approximately 30% for n=5 to approximately 10% for n=30).
This methodology constitutes a new meta-analysis tool that should improve the interpretation of industrial hygiene literature data, but needs to be further validated.
本研究提出了一种程序，可对文献中以不同方式报告的暴露数据进行数值综合，包括汇总参数和单次测量值。该程序应用于有关重组木板材行业甲醛暴露的文献，包括定向刨花板（OSB）、中密度纤维板（MDF）和刨花板（PB）。
对于每篇提供汇总参数的出版物，我们通过假设暴露水平呈对数正态分布来估计几何均值（GM）和几何标准差（GSD）。进行蒙特卡罗模拟，根据样本量以及估计的GM和GSD重新创建数据集，以便随后将其与单次测量值一起格式化。评估了用于估计GM和GSD的方法的精度和偏差。
我们研究中纳入的13篇文章总共产生了一个包含874个数据的最终数据库，其中732个是模拟数据。对于面积数据和个人数据，MDF和PB对应的暴露水平相似，而OSB的水平较低。在压机附近工作时，PB的最新可用个人暴露水平（1985 - 1994年）最高（GM = 0.63毫克/立方米）。在主要生产区域，PB的相应面积暴露水平最高（GM = 0.43毫克/立方米）。拟合面积PB数据的混合效应模型解释了总变异性的38%。估计从1965年到1995年暴露水平下降了6倍。模拟过程的重复产生的计算GM和GSD的相对标准差在10%至20%之间。用于估计GM和GSD的方法的相对偏差因方法而异，并随着样本量的增加而减小（绝对值从n = 5时的约15%降至n = 30时的小于5%）。精度也因方法而异，并随着样本量的增加而提高（从n = 5时的约30%提高到n = 30时的约10%）。
该方法构成了一种新的荟萃分析工具，应能改善对工业卫生文献数据的解读，但需要进一步验证。
