The objectives of the programme are:
- to monitor the frequency of congenital anomalies in different regions of Europe in order to identify any variation that could be due to environmental teratogens or mutagens;
- to create a large data-set, accessible to European scientists, for clinical, etiological, genetic and health service researches;
- to establish an information centre for the promotion and the coordination of surveillance and research activities in the EEC Member States and other countries associated in the COST programmes (COST: European Cooperation in the field of Scientific and Technical Research).
The epidemiological surveillance of congenital anomalies (the EUROCAT programme) was initially an experiment in European surveillance, to assess the feasibility, feasibility of pooling data across national boundaries, both in terms of standardization of definitions, diagnosis and terminology, and in terms of confidentiality. Surveillance was based on a network of regional registries covering geographically defined populations and recording standard epidemiological data on cases of structural malformation, chromosomal abnormality and metabolic defect. The participating registries are supported individually in the member states.
Trends and clusters in time are referred to local registries for investigation. The most important results are as follows:
confirmation of the downward trend of neural tube defects in the British Isles;
a trend towards increasing maternal age which inevitably leads to an increasing total prevalence of Down syndrome;
an increase in urogenital anomalies in many regions which seems to be linked to an increasing use of ultrasound screenings, both prenatally and neonatally.
Geographic variation in the prevalence rate of neural tube defects and facial clefts was demonstrated. Down syndrome also varied in total prevalence, linked to the different maternal age structures of the populations. A number of other anomalies showing geographical variation in rates need further investigation to exclude possible methodological differences.
Prenatal diagnosis is having an increasing impact on the prevalence at birth of anomalies. Considerable variation in prenatal diagnosis impact exists between regions which can be linked to the different screening policies. The increase in prenatal diagnosis and abortion is combining in the British centres with the natural decline in total prevalence to produce a sharp decline in neural tube defect prevalence at birth. Guidelines, newsletters and reports are available. The latest report is EUROCAT Report 6-Surveillance of congenital anomalies in Europe 1980-1992.
One of the prerequisites for effective collaboration between the different centres was the standardization of the data collected, nomenclature and coding. Each case record transmitted to the coordinating centre includes standard information on the baby/fetus, mother, father, exposures and precise diagnoses. By validating centrally this data, by visiting the coordinating centre and local registries, and by organizing meetings for discussions, it has been possible to achieve a high degree of standardization. This however is a continuous process. The great value of comparison between different areas in the interpretation of data has been recognized and exploited.
EUROCAT performs routine monitoring including analysis of trends and identification of clusters and geographical variation. The aim of these analyses is to identify any variation that could be due to environmental teratogens or mutagens. In these analyses the ability to compare different regions following a standard methodology in data collection, and standard definitions and terminology has been extremely valuable. Nevertheless, the results also point to a continuing need for further harmonization between countries.
In 1993, 30 registries in 15 European countries are participating covering all together approximately 400,000 births per year or a roughly 10% sample of the births in the countries in which they are situated. Located initially at the Department of Epidemiology, School of Public Health, Catholic University of Louvain in Brussels (1979-1991), the coordinating centre was transferred in 1992 to the Institute of Hygiene and Epidemiology, Belgian Ministry of Health, in Brussels. The central data base contained 58,000 cases up to 1990. Each case is documented with information on the baby and its precise diagnosis, on the mother, the father and key exposure history.