Report of congenital anomalies surveillance in Spain, on the data registered by ECEMC during the period 1980-2011

Abstract

Aspectos EpidemiológicosCongenital anomalies are a leading cause of perinatal mortality (according to EUROCAT’s data, it reaches a prevalence of 9.4 per 10,000 births). Moreover, the most recent Global Burden of Disease Project estimated that congenital anomalies in 2010 accounted for 732,000 Disability Adjusted Life Years Lost (DALYs) in Western Europe, 274,000 in Central Europe and 898,000 in Eastern Europe. Thus, like other Rare Diseases, congenital anomalies are individually rare but collectively a significant public health issue. This report performed by ECEMC (the Spanish Collaborative Study of Congenital Malformations) is the annual update of the congenital anomalies surveillance report, after having analysed data gathered by this research programme between 1980 and 2011, although ECEMC was created in 1976. It is hospital-based and has a case-control design. The report is based on data from 2,735,086 births surveyed, among which a total of 40,329 presented with congenital anomalies detected during the first 3 days of life. Present coverage of the program is 17.95% of total births in Spain. The time distribution, geographical distribution and spacialtemporal distribution of the frequency of congenital anomalies in Spain were studied. The global frequency of infants with congenital defects has significantly decreased along the time, from the basal frequency registered in 1980-1985 (2.22%) to 1.03% in 2011 (Tables 1 and 3), mainly as a consequence of the impact of terminations of pregnancy after the detection of foetal anomalies (ETOPFA), which has been legal in Spain since the end of 1985. This tendency has also been statistically significant in 14 out of 17 Autonomous Regions and in many participating hospitals (Table 3). Only in Extremadura (see Fig. 1) a significant increase was detected, although the frequency registered in 2011 was not significantly different from ECEMC’s global frequency in the same year. After applying the protocol specifically designed at ECEMC for the study of clusters of birth defects, it was concluded that this increase was probably due to both methodological issues during the first years (with some under-registration of birth defects) and the high quality scrutiny and reporting of newborn infants with congenital anomalies, especially in the province of Cáceres). After correcting the frequency in the different hospitals and Autonomic regions by including ETOPFA cases and referrals to tertiary care hospitals, little changes were observed, mainly due to the difficulties to report ETOPFA cases. The time distribution of the frequency of 33 selected birth defects (Table 4) revealed a statistically significant decrease for most of them, although significant increases were also detected for heart/great vessels defects and unilateral renal agenesis, that were interpreted as a result of the availability of better diagnostic procedures. Also, for the annual distribution of 16 selected birth defects (Graphs-1), significant decreases were observed for all global frequencies except for anotia/microtia and gastroschisis. Regarding the temporal-spatial analyses of the frequency of 18 selected defects (Tables 5-10), the global decreases were also evident in many Autonomous Regions. Only an increase was detected for anencephaly in Aragón, where no clue on a local cause for the increase was observed, and where only one case was registered in 2011. Geographical heterogeneity could be detected in 2011 for several defects and was attributable to the birth of a higher than expected number of cases of anencephaly in Aragón, of cleft lip in Galicia, oesophageal atresia/stenosis in the Canary Islands, and hypospadias in Cantabria. All these clusters were analysed and again no local cause was identified and it was concluded that possibly they are stochastic events, although they will be maintained under close scrutiny until the next surveillance report. Since immigration in Spain has been very remarkable in the last years, the ethnic origin of cases and foreign extraction of their parents were analysed. A statistically significant increase along the time in the percentage of foreign parents was detected (Graph 4), and this was more marked among cases than among controls. Also an increase in all ethnic groups except the oriental one was observed (Graph 5). A higher risk for congenital anomalies was observed for all the groups except the Indian group, with respect to the native white group (Graph 6). Some final comments are included regarding the importance of congenital anomalies registries as infrastructure for the research on their causes and prevention, as well as on the exceptional characteristics of ECEMC’s registry and network (including its international activities for birth defects surveillance), and the need for more campaigns for their primary prevention and more research on their causes. In this sense, a reference is made on Kirby and Browne’s 26 consideration of birth defects surveillance as “an essential public health function for primary prevention and health promotion”.N

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