Objective To compare mortality in children aged <5 years from two causes amenable to healthcare prevention in England and Sweden: respiratory tract infection (RTI) and sudden unexpected death in infancy (SUDI).
Design Birth cohort study using linked administrative health databases from England and Sweden.
Setting and participants Singleton live births between 2003 and 2012 in England and Sweden, followed up from age 31 days until the fifth birthday, death or 31 December 2013.
Main outcome measures The main outcome measures were HR for RTI-related mortality at 31–364 days and at 1–4 years and SUDI mortality at 31–364 days in England versus Sweden estimated using Cox proportional hazards models. We calculated unadjusted HRs and HRs adjusted for birth characteristics (gestational age, birth weight, sex and congenital anomalies) and socioeconomic factors (maternal age and socioeconomic status).
Results The English cohort comprised 3 928 483 births, 768 RTI-related deaths at 31–364 days, 691 RTI-related deaths at 1–4 years and 1166 SUDIs; the corresponding figures for the Swedish cohort were 1 012 682, 131, 118 and 189. At 31–364 days, unadjusted HR for RTI-related death in England versus Sweden was 1.52 (95% CI 1.26 to 1.82). After adjusting for birth characteristics, the HR reduced to 1.16 (95% CI 0.96 to 1.40) and for socioeconomic factors to 1.11 (95% CI 0.92 to 1.34). At 1–4 years, unadjusted HR was 1.58 (95% CI 1.30 to 1.92) and decreased to 1.32 (95% CI 1.09 to 1.61) after adjusting for birth characteristics and to 1.30 (95% CI 1.07 to 1.59) after further adjustment for socioeconomic factors. For SUDI, the respective HRs were 1.59 (95% CI 1.36 to 1.85) in the unadjusted model, and 1.40 (95% CI 1.20 to 1.63) after accounting for birth characteristics and 1.19 (95% CI 1.02 to 1.39) in the fully adjusted model.
Conclusion Interventions that improve maternal health before and during pregnancy to reduce the prevalence of adverse birth characteristics and address poverty could reduce child mortality due to RTIs and SUDIs in England.
- child mortality
- respiratory tract Infection
- sudden unexpected death In infancy
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Contributors AZ, RG, AH and PH conceptualised the study. AZ analysed the data and wrote the first draft of the manuscript. All authors interpreted the data and contributed to the subsequent drafts of the manuscript. All authors have seen and approved the final version.
Funding Funding for this study came from the following sources: AZ was funded by a PhD studentship funded from awards to the Farr Institute of Health Informatics Research, London from the Medical Research Council, Arthritis Research UK, British Heart Foundation, Cancer Research UK, Chief Scientist Office, Economic and Social Research Council, Engineering and Physical Sciences Research Council, National Institute for Health Research (NIHR), National Institute for Social Care and Health Research, and Wellcome Trust (grant MR/K006584/1). PH was supported by an NIHR postdoctoral fellowship (grant number PDF-2013-06-004). PH and RG received support from Health Data Research UK. AZ, PH, RG were (in part) supported by the NIHR Children and Families Policy Research Unit. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. Research at UCL Great Ormond Street Institute of Child Health is supported by the NIHR Great Ormond Street Hospital Biomedical Research Centre.
Competing interests None declared.
Ethics approval We have a data sharing agreement with National Health Service (NHS) Digital to use a de-identified extract of Hospital Episode Statistics linked to Office for National Statistics death registration data; therefore, we did not require ethics approval to use English data sets. We received ethics approval to use the Swedish national registers from the Regional Committee of Stockholm (no 2016/1234-31/5, approved on 4 August 2016).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No data are available.
Patient consent for publication Not required.
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