Spatial modeling using mixed models: an ecologic study of visceral leishmaniasis in Teresina, PiauÝ State, Brazil
Cad. saúde pública
; 18(3): 633-637, maio-jun. 2002.
Artigo
em Inglês
| LILACS
| ID: lil-330944
Biblioteca responsável:
BR526.1
RESUMO
Most ecologic studies use geographical areas as units of observation. Because data from areas close to one another tend to be more alike than those from distant areas, estimation of effect size and confidence intervals should consider spatial autocorrelation of measurements. In this report we demonstrate a method for modeling spatial autocorrelation within a mixed model framework, using data on environmental and socioeconomic determinants of the incidence of visceral leishmaniasis (VL) in the city of Teresina, PiauÝ, Brazil. A model with a spherical covariance structure indicated significant spatial autocorrelation in the data and yielded a better fit than one assuming independent observations. While both models showed a positive association between VL incidence and residence in a favela (slum) or in areas with green vegetation, values for the fixed effects and standard errors differed substantially between the models. Exploration of the data's spatial correlation structure through the semivariogram should precede the use of these models. Our findings support the hypothesis of spatial dependence of VL rates and indicate that it might be useful to model spatial correlation in order to obtain more accurate point and standard error estimates.
Texto completo:
Disponível
Coleções:
Bases de dados internacionais
Base de dados:
LILACS
Assunto principal:
Leishmaniose Visceral
Tipo de estudo:
Estudo de incidência
/
Estudo prognóstico
Limite:
Animais
/
Humanos
País/Região como assunto:
América do Sul
/
Brasil
Idioma:
Inglês
Revista:
Cad. saúde pública
Assunto da revista:
Saúde Pública
/
Toxicologia
Ano de publicação:
2002
Tipo de documento:
Artigo
País de afiliação:
Brasil
/
Estados Unidos
Instituição/País de afiliação:
Harvard School of Public Health/US
/
Universidade Federal do Rio de Janeiro/BR