The contribution of gestational age, area deprivation and mother's country of birth to ethnic variations in infant mortality in England and Wales: A national cohort study using routinely collected data

PLoS One. 2018 Apr 12;13(4):e0195146. doi: 10.1371/journal.pone.0195146. eCollection 2018.


Objectives: We aimed to describe ethnic variations in infant mortality and explore the contribution of area deprivation, mother's country of birth, and prematurity to these variations.

Methods: We analyzed routine birth and death data on singleton live births (gestational age≥22 weeks) in England and Wales, 2006-2012. Infant mortality by ethnic group was analyzed using logistic regression with adjustment for sociodemographic characteristics and gestational age.

Results: In the 4,634,932 births analyzed, crude infant mortality rates were higher in Pakistani, Black Caribbean, Black African, and Bangladeshi infants (6.92, 6.00, 5.17 and 4.40 per 1,000 live births, respectively vs. 2.87 in White British infants). Adjustment for maternal sociodemographic characteristics changed the results little. Further adjustment for gestational age strongly attenuated the risk in Black Caribbean (OR 1.02, 95% CI 0.89-1.17) and Black African infants (1.17, 1.06-1.29) but not in Pakistani (2.32, 2.15-2.50), Bangladeshi (1.47, 1.28-1.69), and Indian infants (1.24, 1.11-1.38). Ethnic variations in infant mortality differed significantly between term and preterm infants. At term, South Asian groups had higher risks which cannot be explained by sociodemographic characteristics. In preterm infants, adjustment for degree of prematurity (<28, 28-31, 32-33, 34-36 weeks) fully explained increased risks in Black but not Pakistani and Bangladeshi infants. Sensitivity analyses with further adjustment for small for gestational age, or excluding deaths due to congenital anomalies did not fully explain the excess risk in South Asian groups.

Conclusions: Higher infant mortality in South Asian and Black infants does not appear to be explained by sociodemographic characteristics. Higher proportions of very premature infants appear to explain increased risks in Black infants but not in South Asian groups. Strategies targeting the prevention and management of preterm birth in Black groups and suboptimal birthweight and modifiable risk factors for congenital anomalies in South Asian groups might help reduce ethnic inequalities in infant mortality.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • African Continental Ancestry Group
  • Asian Continental Ancestry Group
  • Birth Weight
  • Cohort Studies
  • England
  • European Continental Ancestry Group
  • Female
  • Gestational Age*
  • Humans
  • Infant
  • Infant Mortality / ethnology*
  • Infant, Newborn
  • Logistic Models
  • Male
  • Maternal Age
  • Mothers*
  • Parturition
  • Pregnancy
  • Retrospective Studies
  • Risk
  • Sensitivity and Specificity
  • Social Class
  • Treatment Outcome
  • Wales
  • Young Adult

Grant support

This work was supported by the Policy Research Programme in the Department of Health, Award Number: PRP 108/0001 to JJK. This paper reports on an independent study which is funded by the Policy Research Programme in the Department of Health. The views expressed are not necessarily those of the Department. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.