摘要:

AbstractThe influence of age and time factors on the dose‐response relationship will depend on the parameter of risk estimation; e.g., excess risk may increase with age at exposure while relative risk may decrease with age at exposure. “Time since onset of exposure” and “time since last exposure” are probably more important factors to consider than “age at exposure” in most types of occupational

ISSN:0271-3586    

DOI:10.1002/ajim.4700210112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractMisclassification of exposure in epidemiologic investigations has been extensively studied and is now well understood. In contrast, misclassification of confounding factors has been much less investigated. First, we consider a situation with confounding by age, in which misclassification is introduced through stratification of this inherently continuous variable. This misclassification turns out to be benign: 75% of the original confounding is removed by stratification into two age classes and more than 90% by using three age classes. Second, we consider a situation with serious confounding and serious misclassification of the confounding factor but no misclassification of the exposure. In this situation, the misclassification turns out to be of importance. After stratification for the misclassified confounding factor, it appears as though the exposure has a stronger effect on the incidence than the confounder, which is the reverse of the true situation.

ISSN:0271-3586    

DOI:10.1002/ajim.4700210113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractEpidemiological investigation involving historical cohorts requires reconstruction of individual cohort member exposures during the period of study. However, past approaches to exposure assessment by industrial hygienists were characterized by different professional expectations for air sampling, and different orientations for evaluation of air sampling results. The activity designated as “exposure assessment” today was not seriously undertaken prior to the late 1970s. It is important to understand the methodologies utilized in earlier years to assess the quality of workplace air because assumptions of exposure during those years are critically dependent on the utilization of short‐term air sampling results obtained by methods which differ from those employed today.This paper reviews the approaches and methodologies utilized in the United States during the 1930–1980 period to measure airborne concentrations of suspended particulate matter and gaseous contaminants. Specific examples are used to illustrate the obstacles encountered when translating these usually limited data into cumulative exposure indices utilized in testing the hypothesis of a dose‐response relationship in epidemiological investigations. The misuse of these data results in exposure misclassification and obscuration of any dose‐response relationship(s). Selected options for validation of earlier exposures and for increasing or decreasing confidence in recognized incomplete earlier exposure information are discussed.The problems identified and explored in this presentation are inevitable in dealing with available historical occupational exposure data. They will persist for years and demand attention if the information associated with these incomplete data sets is to be defensib

ISSN:0271-3586    

DOI:10.1002/ajim.4700210114

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractExposure data may be inadequate mainly for two reasons; they may not comply with a reasonable exposure‐effect model or they may be biased.In the use of historical data it is essential to keep track of what the data were supposed to mean when collected in the first place. Most measurements of air contaminants in work places are probably carried out to establish compliance or non‐compliance with limit values. Sometimes measurements are also made to evaluate control measures. Unfortunately, measurement data acquired in this way may have very little to do with the true average exposure of employees.The influence of trends and variations in production on the exposure level is substantial. This influence is similar and coincidental in widely different industries. In addition the variations attributed to production levels, there can be important variations due to sea

ISSN:0271-3586    

DOI:10.1002/ajim.4700210115

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:0271-3586    

DOI:10.1002/ajim.4700210116

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:0271-3586    

DOI:10.1002/ajim.4700210101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY