title: Sensitivity analysis of common statistical models used to study the short-term effects of air pollution on health.
abstract: The relationship between photochemical air pollutants (nitrogen dioxide and ozone) and emergency room admissions for asthma in Madrid (Spain) for the period 1995-1998 was analysed using the statistical models commonly used to studying the short-term effects of air pollution on health: linear and Cochrane-Orcutt regression, standard Poisson and Poisson corrected by overdispersion, Poisson autoregressive models, and generalised additive models. Linear regression models presented residual autocorrelation, Poisson regression models also showed overdispersion, and generalised additive models did not show residual autocorrelation and overdispersion was substantially reduced. Linear models provided biased estimates because our health outcome is non-normally distributed. Estimates from Poisson regression allowing for overdispersion and autocorrelation did not differ substantially from those reported by generalised additive models, which present the best model fit in terms of the absence of autocorrelation and reduction of overdispersion.
authors.affiliation: Department of Statistics and Econometrics, Universidad Carlos III de Madrid, C/Madrid 126, E-28903 Getafe, Spain. atobias@est-econ.uc3m.es
authors.forename: Aurelio
authors.initials: A
authors.lastname: Tobías
authors.forename: Marc
authors.initials: M
authors.lastname: Sáez
authors.forename: Iñaki
authors.initials: I
authors.lastname: Galán
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Campbell
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects*; D005544:Forecasting; D006801:Humans; D016014:Linear Models; D011634:Public Health; D012044:Regression Analysis; D012043:Regression, Psychology; D018570:Risk Assessment
chemical_list: D000393:Air Pollutants