Mm. Finkelstein, POTENTIAL PITFALL IN USING CUMULATIVE EXPOSURE IN EXPOSURE-RESPONSE RELATIONSHIPS - DEMONSTRATION AND DISCUSSION, American journal of industrial medicine, 28(1), 1995, pp. 41-47
Cumulative exposure is frequently used as a measure of exposure in the
quantitative analysis of epidemiologic studies. It is recognized that
the imposed symmetry between duration and intensity of exposure is a
potential problem with this measure, but it is less widely recognized
that the finding of an exposure-response relationship, using cumulativ
e exposure as the exposure metric, does not necessarily imply that exp
osures were accurately or even consistently estimated. This report des
cribes a simulation study drawn from a nested case-control analysis of
mesothelioma in a cohort of asbestos cement workers. Intensity of exp
osure in the range of 0.1-40 fibers/ml was randomly assigned to subjec
ts. Logistic regression analysis demonstrated that there was no associ
ation between mesothelioma risk and the randomly assigned intensity of
exposure. However, in 171 (86%) of 200 trials, mesothelioma risk was
significantly associated with cumulative exposure, even though intensi
ty of exposure remained randomly assigned. A strong exposure-response
relationship might thus be misleading. One would be more confident abo
ut quantitative risk assessment when there are a large number of indep
endent studies available for analysis. (C) 1995 Wiley-Liss, Inc.