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On the possible significance of the quadratic effect of age on lung‐function measurements
Author(s) -
Schulzer Michael,
ChanYeung Moira,
Tan Felisa
Publication year - 1982
Publication title -
canadian journal of statistics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.804
H-Index - 51
eISSN - 1708-945X
pISSN - 0319-5724
DOI - 10.2307/3556195
Subject(s) - lung function , quadratic equation , econometrics , identification (biology) , population , variety (cybernetics) , statistics , mathematics , medicine , psychology , lung , environmental health , biology , botany , geometry
The problem of interpreting lung‐function measurements in industrial workers is examined. Two common lung‐function measurements (FEV 1 , and FVC) are described. The standard method currently used in the analysis of such cross‐sectional survey data is discussed. The basic assumption of a linear decline with age is questioned on the basis of large sets of data from a variety of industries in British Columbia. It is shown that, while the linear assumption holds approximately in unexposed. healthy nonsmoking individuals, a quadratic age effect is often observed in smokers and/or in individuals who are industrially exposed to certain fumes or dusts. Recognizing this accelerated rate of deterioration in the lungs is of fundamental importance both to the identification of affected individuals and to the understanding of the process involved. An attempt is made to interpret the variety of nonlinear situations observed, by appealing to population selection mechanisms, individual variations in susceptibility, and the effects due to various levels of stimulus strength.