Spatial Modelling of Preterm Birth Near the Sydney Tar Ponds, Nova Scotia, Canada

Abstract

The major objective of the research is to assess the risk of preterm birth associated with maternal proximity to hazardous waste and pollution from the Sydney Tar Pond sites in Nova Scotia, Canada. The design is spatial modelling of risks of preterm birth in population living in the Cape Breton regional municipality in 1996. The subjects are: 1604 observed cases of preterm birth out of total population of 17559 at risk in 1996. The analysis was done using both the frequentist and the Bayesian approaches. In the frequentist approach, the Poisson model for aggregated data was fitted using the quasi-likelihood approach to accommodate over-dispersion. Weighted regression was also used. In order to accommodate both the random effect and the anticipated spatial effects, Bayesian hierarchical modelling was also used to fit the Poisson model. The result of the Bayesian modelling shows that there is no significant spatial association of risk in the area studied. All the models also show that there is no decrease in risk of preterm birth as we move from the Tar Pond site to other region. None of the other covariates in the model show any significant association with increase risk of preterm birth either. There was no obvious clustering of risk in any region or part.