Using a Clustering Approach to Investigate Socio-Environmental Inequality in Preterm Birth-A Study Conducted at Fine Spatial Scale in Paris (France)

Abstract

Background & Objectives: Today, to support public policies aiming to tackle environmental and health inequality, identification and monitoring of the spatial pattern of adverse birth outcomes are crucial. Spatial identification of the more vulnerable population to air pollution may orient health interventions. In this context, the objective of this study is to investigate the geographical distribution of the risk of preterm birth (PTB, gestational age ≤36 weeks) at the census block level in in city of Paris, France. We also aimed to assess the implication of neighborhood characteristics including air pollution and socio-economic deprivation. Material & Methods: Newborn health data are available from the first birth certificate registered by the Maternal and Child Care department of Paris. All PTB from January 2008 to December 2011 were geocoded at the mother residential census block. Each census block was assigned a socioeconomic deprivation level and annual average ambient concentrations of NO₂. A spatial clustering approach was used to investigate the spatial distribution of PTB. Results: Our results highlight that PTB is non-randomly spatially distributed, with a cluster of high risk in the northeastern area of Paris (RR = 1.15; p = 0.06). After adjustment for socio-economic deprivation and NO₂ concentrations, this cluster becomes not statistically significant or shifts suggesting that these characteristics explain the spatial distribution of PTB; further, their combination shows an interaction in comparison with SES or NO₂ levels alone. Conclusions: Our results may inform the decision makers about the areas where public health efforts should be strengthened to tackle the risk of PTB and to choose the most appropriate and specific community-oriented health interventions.

Keywords: air pollution; neighborhood deprivation index; preterm birth; spatial approach.

Figure 1

(A): Spatial distribution of crude preterm birth rate in census block areas within Paris; (B): Spatial distribution of socio-economic deprivation index in census block areas within Paris; (C): Spatial distribution of NO₂ average concentrations from 2008 to 2011 in census block areas within Paris.

Figure 1

(A): Spatial distribution of crude preterm birth rate in census block areas within Paris; (B): Spatial distribution of socio-economic deprivation index in census block areas within Paris; (C): Spatial distribution of NO₂ average concentrations from 2008 to 2011 in census block areas within Paris.

Figure 2

Spatial relocation of the most likely cluster of unadjusted PTB risk (A); after adjustment for NO₂ exposure (B); after adjustment for NO₂ exposure and socio-economic level (C). Legend: the dark area represents the census blocks included in the most likely cluster of high risk of PTB.