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BMJ. 2015 Nov 24;351:h5949. doi: 10.1136/bmj.h5949.

Long term trends in prevalence of neural tube defects in Europe: population based study.

Author information

1
Obstetrical, Perinatal and Pediatric Epidemiology Research Team, Center for Biostatistics and Epidemiology, INSERM U1153, Maternité de Port-Royal, 75014 Paris, France babak.khoshnood@inserm.fr.
2
EUROCAT Central Registry, Centre for Maternal, Fetal and Infant Research, Institute of Nursing Research, University of Ulster, Newtownabbey, UK.
3
EUROCAT Northern Netherlands Registry, University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, Netherlands.
4
Public Health Division of Gipuzkoa, Instituto BIO-Donostia Basque Government CIBER Epidemiología y Salud Pública - CIBERESP, San Sebatian, Spain.
5
Service de Genetique Medicale Maternite, CHUV, Lausanne, Switzerland.
6
Children's University Hospital of Zagreb, Clinical Hospital Sisters of Mercy, Zagreb, Croatia.
7
National Institute of Health Development, Department of Hungarian Congenital Abnormality Registry and Surveillance, Budapest, Hungary.
8
CNR Institute of Clinical Physiology and Tuscany Registry of Congenital Defects, "Gabrielle Monasterio" Foundation, Pisa, Italy.
9
Instituto Nacionale de Saude Dr. Ricardo Jorge, Lisbon, Portugal.
10
Department of Health Sciences, University of Leicester, Leicester, UK.
11
Hospital Lillebaelt, Kolding, Denmark.
12
Department of Health Information and Research, Guardamangia, Malta.
13
Medical University of Graz, Graz, Austria.
14
Medical Birth Registry of Norway, Norwegian Institute of Public Health and Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
15
Department of Medical Genetics, University of Medical Sciences, Poznan, Poland.
16
Public Health Department, HSE South, Lacken, Kilkenny, Ireland.
17
Health Service Executive, Dublin, Ireland.
18
Provincial Institute for Hygiene, Antwerp, Belgium.
19
Registro IMER - IMER Registry (Emilia Romagna Registry of Birth Defects), Center for Clinical and Epidemiological Research, University of Ferrara, Ferrara, Italy.
20
Department of Public Health, Health Service Executive - South, Ireland.
21
Birth Registry Mainz Model, Childrens Hospital, University Medical Center, Johannes Gutenberg-University, Mainz, Germany.
22
Institute of Health and Society, Newcastle University, Newcastle, UK.
23
Malformation Monitoring Centre Saxony-Anhalt, Medical Faculty Otto-von-Guericke University, Magdeburg, Germany.
24
National Institute for Health and Welfare, Helsinki, Finland.
25
National Perinatal Epidemiology Unit, University of Oxford, Oxford, UK.
26
National Registry of Congenital Anomalies of the Czech Republic, Department of Medical Genetics, Thomayer University Hospital, Prague, Czech Republic.
27
Public Health Wales, Swanseaa, UK.
28
Center for Human Genetics, Institut de Recherche Scientifique en Pathologie et en Génétique, Charleroi, Belgium.
29
University Hospitals Southampton, Faculty of Medicine and Wessex Clinical Genetics Service, Southampton, UK.

Abstract

STUDY QUESTION:

What are the long term trends in the total (live births, fetal deaths, and terminations of pregnancy for fetal anomaly) and live birth prevalence of neural tube defects (NTD) in Europe, where many countries have issued recommendations for folic acid supplementation but a policy for mandatory folic acid fortification of food does not exist?

METHODS:

This was a population based, observational study using data on 11,353 cases of NTD not associated with chromosomal anomalies, including 4162 cases of anencephaly and 5776 cases of spina bifida from 28 EUROCAT (European Surveillance of Congenital Anomalies) registries covering approximately 12.5 million births in 19 countries between 1991 and 2011. The main outcome measures were total and live birth prevalence of NTD, as well as anencephaly and spina bifida, with time trends analysed using random effects Poisson regression models to account for heterogeneities across registries and splines to model non-linear time trends.

SUMMARY ANSWER AND LIMITATIONS:

Overall, the pooled total prevalence of NTD during the study period was 9.1 per 10,000 births. Prevalence of NTD fluctuated slightly but without an obvious downward trend, with the final estimate of the pooled total prevalence of NTD in 2011 similar to that in 1991. Estimates from Poisson models that took registry heterogeneities into account showed an annual increase of 4% (prevalence ratio 1.04, 95% confidence interval 1.01 to 1.07) in 1995-99 and a decrease of 3% per year in 1999-2003 (0.97, 0.95 to 0.99), with stable rates thereafter. The trend patterns for anencephaly and spina bifida were similar, but neither anomaly decreased substantially over time. The live birth prevalence of NTD generally decreased, especially for anencephaly. Registration problems or other data artefacts cannot be excluded as a partial explanation of the observed trends (or lack thereof) in the prevalence of NTD.

WHAT THIS STUDY ADDS:

In the absence of mandatory fortification, the prevalence of NTD has not decreased in Europe despite longstanding recommendations aimed at promoting peri-conceptional folic acid supplementation and existence of voluntary folic acid fortification.

FUNDING, COMPETING INTERESTS, DATA SHARING:

The study was funded by the European Public Health Commission, EUROCAT Joint Action 2011-2013. HD and ML received support from the European Commission DG Sanco during the conduct of this study. No additional data available.

PMID:
26601850
PMCID:
PMC4658393
DOI:
10.1136/bmj.h5949
[Indexed for MEDLINE]
Free PMC Article

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