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Trends in socioeconomic inequalities in risk of sudden infant death syndrome, other causes of infant mortality, and stillbirth in Scotland: population based study

BMJ 2012; 344 doi: http://dx.doi.org/10.1136/bmj.e1552 (Published 16 March 2012) Cite this as: BMJ 2012;344:e1552
  1. Angela M Wood, lecturer1,
  2. Dharmintra Pasupathy, NIHR clinical lecturer2,
  3. Jill P Pell, professor3,
  4. Michael Fleming, statistician4,
  5. Gordon C S Smith, professor5
  1. 1Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
  2. 2Women’s Health Academic Centre, King’s Health Partners, King’s College London, London SE1 7EH
  3. 3Public Health Unit, University of Glasgow, Glasgow G12 8RZ
  4. 4Information Services Division, NHS National Services Scotland, Edinburgh EH12 9EB
  5. 5Department of Obstetrics and Gynaecology, NIHR Biomedical Research Centre, University of Cambridge, Cambridge CB2 0SW
  1. Correspondence to: G C S Smith gcss2{at}cam.ac.uk
  • Accepted 25 January 2012

Abstract

Objectives To compare changes in inequalities in sudden infant death syndrome with other causes of infant mortality and stillbirth in Scotland, 1985-2008.

Design Retrospective cohort study.

Setting Scotland 1985-2008, analysed by four epochs of six years.

Participants Singleton births of infants with birth weight >500 g born at 28-43 weeks’ gestation.

Main outcome measures Sudden infant death syndrome, other causes of postneonatal infant death, neonatal death, and stillbirth. Odds ratios expressed as the association across the range of seven categories of Carstairs deprivation score.

Results The association between deprivation and the risk of all cause stillbirth and infant death varied between the four epochs (P=0.04). This was wholly explained by variation in the risk of sudden infant death syndrome (P<0.001 for interaction). Among women living in areas of low deprivation, there was a sharp decline in the rate of sudden infant death syndrome from 1990 to 1993. Among women living in areas of high deprivation, there was a slower decline in sudden infant death syndrome rates between 1992 and 2004. Consequently, the odds ratio for the association between socioeconomic deprivation and sudden infant death syndrome increased from 2.04 (95% confidence interval 1.53 to 2.72) in 1985-90, to 7.52 (4.62 to 12.25) in 1991-6, and 9.50 (5.46 to 16.53) in 1997-2002 but fell to 1.78 (0.87 to 3.65) in 2002-8. The interaction remained significant after adjustment for maternal characteristics.

Conclusion The rate of sudden infant death syndrome declined throughout Scotland in the early 1990s. The decline had a later onset and was slower among women living in areas of high deprivation, probably because of slower uptake of recommended changes in infant sleeping position. The effect was to create a strong independent association between deprivation and sudden infant death syndrome where one did not exist before.

Footnotes

  • Contributors: GCSS had the original idea. MF performed the record linkage and extracted the data. GCSS, DP, and AMW designed and performed the statistical analysis and drafted the paper. All authors contributed to editing the draft for content and edited and approved the final version of the paper. GCSS is guarantor.

  • Funding: The study was supported by the NIHR Cambridge Comprehensive Biomedical Research Centre. DP was funded by an MRC clinical training fellowship. The funding bodies had no role in any aspect of the conduct, analysis, or presentation of this study.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The work was approved by the privacy advisory committee of the information services division of NHS Scotland.

  • Data sharing: Requests for the raw data from this study should be made directly to the information services division of NHS Scotland.

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