The Po River Delta epidemiological study of obstructive lung disease: sampling methods, environmental and population characteristics

Abstract

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.

Skin prick test reactivity to common aeroallergens in relation to total IgE, respiratory symptoms, and smoking in a general population sample of northern Italy

“…The population described in this report is a sample randomly selected, and stratified for age and socioeconomic status, that has been shown to be representative of the general population living in the area (2). Thus, the results obtained in our sample represent the distribution of reactivity to common aeroallergens in this general population living in a rural area of northern Italy.…”

“…The first cross-sectional survey ( 1980-82) was performed before the start of operation of the power plant (1982), when the Po delta area was largely unpolluted (2); subjects lived in a rural area where agriculture, fishing, and commerce predominated, and few jobs had important occupational exposures to known bronchoirritants.…”

“…Sampling methods, population characteristics, the National Research Council (CNR) questionnaire for symptoms and risk factors, lung function tests in normal and in symptomatic subjects, and the effects of environmental risk factors have been described previously (2,15).…”

“…IgE values were also significantly associated with SPT reactivity. In conclusion, our findings indicate that almost one-third of the general population of an Italian rural area is skin test positive, emphasizing the importance of assessing atopy in respiratory epidemiologic surveys.A series of respiratory epidemiologic studies in general population samples was carried out over the last years to improve our knowledge of the natural history of airways obstructive disease (AOD) (1,2). These studies aimed at evaluating the frequency of AOD in different geographic areas and the role of risk factors such as cigarette smoking, occupational exposure to bronchoirritant agents, familial predisposition t o AOD, childhood respiratory illnesses, outdoor and indoor pollution, and atopy ( 3 , 4).…”

“…A series of respiratory epidemiologic studies in general population samples was carried out over the last years to improve our knowledge of the natural history of airways obstructive disease (AOD) (1,2). These studies aimed at evaluating the frequency of AOD in different geographic areas and the role of risk factors such as cigarette smoking, occupational exposure to bronchoirritant agents, familial predisposition t o AOD, childhood respiratory illnesses, outdoor and indoor pollution, and atopy ( 3 , 4).…”