Open Access Highly Accessed Research article

No improvement in socioeconomic inequalities in birthweight and preterm birth over four decades: a population-based cohort study

Svetlana V Glinianaia14*, Rakesh Ghosh2, Judith Rankin1, Mark S Pearce1, Louise Parker3 and Tanja Pless-Mulloli1

Author Affiliations

1 Institute of Health & Society, Newcastle University, Newcastle upon Tyne, England, UK

2 Department of Public Health Sciences, University of California, Davis, USA

3 Departments of Medicine and Pediatrics, Dalhousie University, Halifax, NS, Canada

4 Institute of Health & Society, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK

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BMC Public Health 2013, 13:345  doi:10.1186/1471-2458-13-345

Published: 15 April 2013

Abstract

Background

Birthweight and gestational age are associated with socioeconomic deprivation, but the evidence in relation to temporal changes in these associations is sparse. We investigated changes in the associations between socioeconomic status (SES) and birthweight and gestational age in Newcastle upon Tyne, North of England, during 1961–2000.

Methods

We used population-based data from hospital neonatal records on all singleton births to mothers resident in Newcastle (births with complete covariate information n = 113,182). We used linear regression to analyse the associations between neighbourhood SES and birthweight over the entire 40-year period and by decade, and logistic regression for associations with low birthweight (LBW) and preterm birth, adjusting for potential confounders.

Results

There was a significant interaction between SES and decade of birth for birthweight (p = 0.028) and preterm birth (p < 0.001). Socioeconomic gradients were similar in each decade for birthweight outcomes, but for preterm birth, socioeconomic disparities were more evident in the later decades [for 1961–70, odds ratio (OR) was 1.1, 95% CI 0.9, 1.3, for the most deprived versus the least deprived quartile, while for 1991–2000, the corresponding OR was 1.5, 95% CI 1.3, 1.7]. In each decade, there was a significant decrease in birthweight adjusted for gestational age for the most deprived compared to the least deprived SES group [1961–1970: –113.4 g (95% CI–133.0, –93.8); 1991–2000: –97.5 g (95% CI–113.0, –82.0)], while there was a significant increase in birthweight in each SES group over time.

Conclusions

Socioeconomic inequalities did not narrow over the four decades for birthweight and widened for preterm birth. Mean birthweight adjusted for gestational age increased in all socioeconomic groups, suggesting an overall increase in fetal growth.

Keywords:
Low birthweight; Preterm birth; Socioeconomic status; Townsend deprivation score; Temporal trends