SEDL / STP / STP872-EB / STP32846S

Collection and Analysis of Symptom Data in Clinical Air Pollution Studies

Hackney, JD
Chief, Environmental Health Service, and professor of medicine, and senior project scientist, Environmental Health Service, Rancho Los Amigos Hospital, University of Southern California, Downey, CA

Linn, WS
Chief, Environmental Health Service, and professor of medicine, and senior project scientist, Environmental Health Service, Rancho Los Amigos Hospital, University of Southern California, Downey, CA

Pages: 10    Published: Jan 1985

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Abstract

Symptoms represent an important dimension of people's responses to irritant air pollutants and deserve careful attention in clinical exposure studies. Scientific investigation is handicapped somewhat in that symptoms cannot be verified objectively, nor can they be quantitated rigorously like common physiological observations. Symptom evaluations in exposure studies may take the form of verbal descriptions, incidence or prevalence rates (counts of symptomatic versus asymptomatic subjects), or scores on an arbitrary ordinal scale (for example, with larger numbers representing greater degrees of severity). Our experience supports the use of written multiple-choice questionnaires with ordinal scoring. In groups of subjects large enough for meaningful statistical analyses, the questionnaire technique compares favorably with pulmonary physiological tests, in terms of its sensitivity in detecting responses to pollutant exposure. However, any given individual may show little correlation between symptoms and physiological response. Widespread standardization of symptom questionnaires has been useful in epidemiology and should by considered in clinical exposure studies.