Carrozzi L, Giuliano G, Viegi G, Paoletti P, Di Pede F, Mammini U, Carmignani G, Saracci R, Giuntini C, Lebowitz M D
CNR Institute of Clinical Physiology, University of Pisa, Italy.
Eur J Epidemiol. 1990 Jun;6(2):191-200. doi: 10.1007/BF00145793.
A longitudinal study on chronic obstructive lung disease (AOD) has been started in the Po River Delta in northern Italy. The first cross-sectional study was conducted in this previously unpolluted rural area before the start of operation of a large thermoelectric power plant (2,649 megawatt). A significant output of air pollutants is expected. This will permit us to carry out a "natural experiment" to study the effects of air pollutants (SO2 and suspended particulates). A multistage stratified cluster design was chosen. Stratification was based on age and socio-economic characteristics (SES) of households, and was performed in two steps, using the different indices computed from the census data. Geographic zones represented four areas of different predicted pollution exposure, once the plant started operating. There were 3,289 subjects in the selected age group (8-64) who agreed to participate (78%); only 11% refused to participate. The participants were representative of the clusters and SES. Participants had slightly fewer employed males, who did not participate due to work. The stratification and staging method allowed us to keep an acceptable level of precision and efficiency in the sample. In fact age-related differences were not found among the SES strata and geographic zones; various socio-economic characteristics, verified from the questionnaire information, were consistent with the SES stratification. Differences between geographic zones were related to the number of households of different SES within clusters; however this reflects the characteristics of the general population in the area.
一项关于慢性阻塞性肺病（AOD）的纵向研究已在意大利北部的波河三角洲启动。第一项横断面研究是在一座大型热电厂（2649兆瓦）投产之前，在这个此前未受污染的农村地区进行的。预计会有大量空气污染物排放。这将使我们能够开展一项“自然实验”，以研究空气污染物（二氧化硫和悬浮颗粒物）的影响。研究采用了多阶段分层整群设计。分层基于家庭的年龄和社会经济特征（SES），分两步进行，使用从人口普查数据计算得出的不同指标。一旦工厂开始运营，地理区域代表了四个预计污染暴露程度不同的区域。在选定的年龄组（8 - 64岁）中有3289名受试者同意参与（78%）；只有11%的人拒绝参与。参与者代表了各个群组和社会经济特征。参与的在职男性略少，他们因工作未参与。分层和分阶段方法使我们能够在样本中保持可接受的精度和效率水平。事实上，在社会经济阶层和地理区域之间未发现与年龄相关的差异；从问卷信息核实的各种社会经济特征与社会经济分层一致。地理区域之间的差异与群组内不同社会经济状况的家庭数量有关；然而，这反映了该地区总体人口的特征。
