[Interpretation problems in the analysis of temporal series of air pollution and health. Part II: significance of outcome variables, relations forms, effect modifiers, and mechanisms of action].
This paper is a commentary to the MISA study (Meta-analysis of Italian studies on short-term effects of air pollution). The interpretation of the relationships observed in the time-series analyses is not straightforward. I will review a number of open questions: the exposure estimates; the meaning of the daily mortality and hospitalisation rates, in terms of impact on life expectancy, incidence of specific diseases, exacerbation of preexisting chronic diseases; the pattern of the estimated dose-response curves; the role of possible effect modifiers; the hypotheses about the underlying mechanisms. These interpretative problems often present overlapping aspects. Some of the pending answers are relevant for policy making. For editorial reasons this review is divided in two parts. A first paper, focusing on the exposure estimates, has been published on the previous issue of this journal. This second part deals with the meaning of the outcome variable, the shape of the dose-response curves, possible effect modifiers and underlying mechanisms.
Lagorio
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Laboratorio di igiene ambientale, Istituto superiore di sanità, Roma. lagorio@iss.it
D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D006801:Humans