1. Ecole de Santé Publique. Université de Montréal, Québec, Canada.
The influence of naturalization length on low birth weight among immigrants in Belgium
Judith Racape 1
Claudia Schoenborn 1,2
Mouctar Sow 2,3
Myriam De Spiegelaere 2
Centre de Recherche en Epidémiologie, Biostatistique et Recherche clinique. Ecole de Santé Publique, Université Libre de Bruxelles (ULB), Belgique
Centre de Recherche en Politique et Système de Santé. Ecole de Santé Publique, Université Libre de Bruxelles (ULB), Belgique.
Ecole de Santé Publique. Université de Montréal, Québec, Canada.

2. Introduction
Perinatal outcomes have been extensively studied among immigrant women in different high-income countries showing conflicting results (Gagnon et al., 2009)
Acculturation paradox (Lopez-Class et al., 2011)
Previous research in Belgium have also shown paradoxical results depending on perinatal outcomes, socioeconomic factors and immigrant status studied (Racape et al. 2010,2013,2016)
The interaction between social determinants and migration trajectory remains poorly understood

3. Objectives
To analyse Low birth Weight (LBW) among immigrants according to socioeconomic factors and naturalization length
Analyse the socioeconomic status (SES) among immigrants depending on naturalization length
Analyse the association between LBW and naturalization length among immigrants

4. Methods
Data:
Linkage between the birth and death certificates taken from the Belgian civil registration system, the national register and the BCSS (Banque Carrefour de la Securite Sociale)
All singleton live births between 1st January 2004 and 31st December 2010 in Brussels

5. Methods Low Birth Weight (LBW) : < 2500 gr
Socioeconomic status (SES)
Single mother
Incomes (Quintile: Q1, Q2-Q3, Q4-Q5)
Maternal education (primary, secondary, superior)
Immigrant status
Maternal nationality
Naturalization length : < 1, 1-5, 5-10 and > 10 years

6. Methods
Maternal nationality (at her own birth and at the child’s birth)
Belgian (n = )
Maghreb (n = )
Belgian origin Maghreb (n = )
Sub-Saharan Africa (n = 4 989)
Belgian origin sub-Saharan Africa (n = 4 917)
Turkey (n = 1 839)
Belgian origin Turkey (n = 4 425)
We used a logistic regression to estimate the ORs for the association between LBW according to nationality and naturalization length after adjusting for SES

7. Higher maternal education according to naturalization length
***
***
***
***
***
***
***
***
***
*** p<0,0001

8. Poverty line (Q1) according to naturalization length
***
***
***
***
***
***
***
***
***
*** p<0,0001 *

9. Crude OR of LBW according to naturalization length (ref: Belgian)
1,4
1,2
0,8 * **

10. Adjusted OR of LBW according to naturalization length (ref: Belgian)*

11. Conclusion
Significant increase of LBW with naturalization length despite an increase of SES among all our migrant groups
Protection of LBW among Magrebi mother is maintain even after 10 years of naturalization
Inverse social health gradient among our migrant groups
What are immigrant familiies’ protective environments ?
What happens during naturalization ?