Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities

The objective of this paper is to introduce a diVerent approach, called the ecological-longitudinal, to carrying out pooled analysis in time series ecological studies. Because it gives a larger number of data points and, hence, increases the statistical power of the analysis, this approach, unlike c...

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Autores: Sáez Zafra, Marc, Figueiras, Adolfo, Ballester, Ferran, Pérez Hoyos, Santiago, Ocaña, Ricardo, Tobías, Aurelio
Tipo de recurso: artículo
Fecha de publicación:2001
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:10256/3541
Acceso en línea:http://hdl.handle.net/10256/3541
Access Level:acceso abierto
Palabra clave:Aire -- Contaminació
Contaminants
Mortalitat
Air -- Pollution
Mortality
Pollutants
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spelling Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish citiesSáez Zafra, MarcFigueiras, AdolfoBallester, FerranPérez Hoyos, SantiagoOcaña, RicardoTobías, AurelioAire -- ContaminacióContaminantsMortalitatAir -- PollutionMortalityPollutantsThe objective of this paper is to introduce a diVerent approach, called the ecological-longitudinal, to carrying out pooled analysis in time series ecological studies. Because it gives a larger number of data points and, hence, increases the statistical power of the analysis, this approach, unlike conventional ones, allows the complementation of aspects such as accommodation of random effect models, of lags, of interaction between pollutants and between pollutants and meteorological variables, that are hardly implemented in conventional approaches. Design—The approach is illustrated by providing quantitative estimates of the short-termeVects of air pollution on mortality in three Spanish cities, Barcelona,Valencia and Vigo, for the period 1992–1994. Because the dependent variable was a count, a Poisson generalised linear model was first specified. Several modelling issues are worth mentioning. Firstly, because the relations between mortality and explanatory variables were nonlinear, cubic splines were used for covariate control, leading to a generalised additive model, GAM. Secondly, the effects of the predictors on the response were allowed to occur with some lag. Thirdly, the residual autocorrelation, because of imperfect control, was controlled for by means of an autoregressive Poisson GAM. Finally, the longitudinal design demanded the consideration of the existence of individual heterogeneity, requiring the consideration of mixed models. Main results—The estimates of the relative risks obtained from the individual analyses varied across cities, particularly those associated with sulphur dioxide. The highest relative risks corresponded to black smoke in Valencia. These estimates were higher than those obtained from the ecological-longitudinal analysis. Relative risks estimated from this latter analysis were practically identical across cities, 1.00638 (95% confidence intervals 1.0002, 1.0011) for a black smoke increase of 10 μg/m3 and 1.00415 (95% CI 1.0001, 1.0007) for a increase of 10 μg/m3 of sulphur dioxide. Because the statistical power is higher than in the individual analysis more interactions were statistically significant,especially those among air pollutants and meteorological variables. Conclusions—Air pollutant levels were related to mortality in the three cities of the study, Barcelona, Valencia and Vigo. These results were consistent with similar studies in other cities, with other multicentric studies and coherent with both, previous individual, for each city, and multicentric studies for all three citiesBMJ Publishing Group2001info:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10256/3541http://hdl.handle.net/10256/3541Journal of Epidemiology and Community Health, 2001, vol. 55, núm. 6, p.423-432Articles publicats (D-EC)reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)Inglésinfo:eu-repo/semantics/altIdentifier/issn/0143-005Xinfo:eu-repo/semantics/altIdentifier/eissn/1470-2738Aquest document està subjecte a una llicència Creative Commons: Reconeixement – No comercial (by-nc)http://creativecommons.org/licenses/by-nc/3.0/es/deed.cainfo:eu-repo/semantics/openAccessoai:recercat.cat:10256/35412026-05-29T05:05:01Z
dc.title.none.fl_str_mv Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities
title Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities
spellingShingle Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities
Sáez Zafra, Marc
Aire -- Contaminació
Contaminants
Mortalitat
Air -- Pollution
Mortality
Pollutants
title_short Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities
title_full Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities
title_fullStr Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities
title_full_unstemmed Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities
title_sort Comparing meta-analysis and ecological-longitudinal analysis in time-series studies: a case study of the effects of air pollution on mortality in three Spanish cities
dc.creator.none.fl_str_mv Sáez Zafra, Marc
Figueiras, Adolfo
Ballester, Ferran
Pérez Hoyos, Santiago
Ocaña, Ricardo
Tobías, Aurelio
author Sáez Zafra, Marc
author_facet Sáez Zafra, Marc
Figueiras, Adolfo
Ballester, Ferran
Pérez Hoyos, Santiago
Ocaña, Ricardo
Tobías, Aurelio
author_role author
author2 Figueiras, Adolfo
Ballester, Ferran
Pérez Hoyos, Santiago
Ocaña, Ricardo
Tobías, Aurelio
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Aire -- Contaminació
Contaminants
Mortalitat
Air -- Pollution
Mortality
Pollutants
topic Aire -- Contaminació
Contaminants
Mortalitat
Air -- Pollution
Mortality
Pollutants
description The objective of this paper is to introduce a diVerent approach, called the ecological-longitudinal, to carrying out pooled analysis in time series ecological studies. Because it gives a larger number of data points and, hence, increases the statistical power of the analysis, this approach, unlike conventional ones, allows the complementation of aspects such as accommodation of random effect models, of lags, of interaction between pollutants and between pollutants and meteorological variables, that are hardly implemented in conventional approaches. Design—The approach is illustrated by providing quantitative estimates of the short-termeVects of air pollution on mortality in three Spanish cities, Barcelona,Valencia and Vigo, for the period 1992–1994. Because the dependent variable was a count, a Poisson generalised linear model was first specified. Several modelling issues are worth mentioning. Firstly, because the relations between mortality and explanatory variables were nonlinear, cubic splines were used for covariate control, leading to a generalised additive model, GAM. Secondly, the effects of the predictors on the response were allowed to occur with some lag. Thirdly, the residual autocorrelation, because of imperfect control, was controlled for by means of an autoregressive Poisson GAM. Finally, the longitudinal design demanded the consideration of the existence of individual heterogeneity, requiring the consideration of mixed models. Main results—The estimates of the relative risks obtained from the individual analyses varied across cities, particularly those associated with sulphur dioxide. The highest relative risks corresponded to black smoke in Valencia. These estimates were higher than those obtained from the ecological-longitudinal analysis. Relative risks estimated from this latter analysis were practically identical across cities, 1.00638 (95% confidence intervals 1.0002, 1.0011) for a black smoke increase of 10 μg/m3 and 1.00415 (95% CI 1.0001, 1.0007) for a increase of 10 μg/m3 of sulphur dioxide. Because the statistical power is higher than in the individual analysis more interactions were statistically significant,especially those among air pollutants and meteorological variables. Conclusions—Air pollutant levels were related to mortality in the three cities of the study, Barcelona, Valencia and Vigo. These results were consistent with similar studies in other cities, with other multicentric studies and coherent with both, previous individual, for each city, and multicentric studies for all three cities
publishDate 2001
dc.date.none.fl_str_mv 2001
dc.type.none.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10256/3541
http://hdl.handle.net/10256/3541
url http://hdl.handle.net/10256/3541
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0143-005X
info:eu-repo/semantics/altIdentifier/eissn/1470-2738
dc.rights.none.fl_str_mv http://creativecommons.org/licenses/by-nc/3.0/es/deed.ca
info:eu-repo/semantics/openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc/3.0/es/deed.ca
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv BMJ Publishing Group
publisher.none.fl_str_mv BMJ Publishing Group
dc.source.none.fl_str_mv Journal of Epidemiology and Community Health, 2001, vol. 55, núm. 6, p.423-432
Articles publicats (D-EC)
reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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