Neural tube defects in Quebec. A search for evidence of 'clustering' in time and place (original) (raw)
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Neural tube defects in New South Wales, Australia
Journal of Medical Genetics, 1978
Cases of spina bifida cystica, encephalocele, and anencephaly occurring over a 9-year period, 1965 to 1973, in New South Wales, Australia, were identified. A low frequency of 1 1 for spina bifida and encephalocele (SB) and 0-9 for anencephaly (A) was found. Secular trends parallel to those observed in the northern hemisphere were noted. Detailed analysis of 1575 cases showed an excess of births in spring, corresponding with conception in the summer months, after correction for shorter gestation in anencephalus, which varies from the peak of spring conceptions observed in British studies. An excess of female cases for each abnormality and a social class effect with a deficit of cases in classes I and II and an excess in classes IV and V and ex-nuptial births were apparent. The first birth rank for younger mothers did not show a significantly increased risk; however, the effect of high birth rank and older maternal age was more significant. Migration studies showed that in migrating from areas of high incidence these parents maintain a higher risk than the Australian population. The highest risk group was that in which both parents were born in the UK, and the next highest that in which an English-born mother was married to an Australian father. Mothers from Malta, and either or both parents from Lebanon, Egypt, and Austria were also at high risk. Part-aboriginal children had a higher risk rate for ASB than white Australian children. The proportion of older sibs affected was 4.12% of sibs of both sexes of an index case of spina bifida, and 3.19% of an index case of anencephaly. The abnormalities alternate or recur in families. An increased perinatal mortality rate in sibs was shown. Twin studies showed a higher concordance rate for monochorionic pairs. A sequential interaction in an excess of opposite sex sib before an index case was apparent. The results of this study support a multifactorial aetiology for ASB resulting from genetic environmental interaction. New South Wales is the eastern coastal state of Australia, with an area of 309 433 square miles and a population of 4 640 800 at the 1971 Census. The continent is geographically isolated with a large migrant population, seasonal reversal, and a hot climate. Methods Records for 1965 to 1967 were incomplete; further cases were identified by examination of labour ward There were 712 cases of anencephalus identified from registers in obstetric hospitals and by letter to country stillbirth and neonatal death registrations at the NSW centres. Registrar General's Department International Classifi-One hundred and forty-two cases of encephalocele cation of Disease (ICD) 7409. Cases registered as (ICD 7430), and 721 of meningomyelocele (7410, 'monster' and 'multiple congenital abnormalities' were 7419), stillborn, and registered as perinatal deaths or excluded unless definite anatomical evidence of neural deaths aged 1 month to 9 years from 1 January 1965 tube malformation could be confirmed. to 30 December 1975, were obtained from the Bureau of Census and Statistics and the Registrar General's
Teratology, 1991
In the period 1980-1987, neural tube defects were two to three times more prevalent in populations covered by EUROCAT registries in the United Kingdom and Ireland (UKI) than in Continental Europe and Malta (CEM). 1864 NTD cases in a total population of 580,000 births in UKI and 455 cases in a population of 380,000 births in CEM were analysed to find if there were differences in the ratio of prevalence rates between UKI and CEM according to site of the defect and association with non-central nervous system (CNS) anomalies. The prevalence rate ratio was high for anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida, and low for encephalocele, lower spina bifida, and anencephaly without other neural tube defects. There was a greater female excess for anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida than for other defects in both geographic areas. There was a female excess for encephalocele in UKI but a male excess in CEM. Certain sites (anencephaly with accompanying spina bifida, iniencephaly, and encephalocele) were more likely to have accompanying non-CNS anomalies. The prevalence rate ratio of multiply malformed NTD was in general lower than for isolated NTD but showed the same pattern by site. The prevalence rate ratio was high for multiply malformed anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida. The sex ratio was similar between isolated and multiply malformed cases when site of the defect is taken into account. It is concluded that the geographic prevalence pattern and sex ratio differ according to site of NTD but do not differ substantially according to whether NTD is isolated or associated with non-CNS anomalies.
Teratology, 1997
Problem/Condition: The reported prevalence of anencephaly and spina bifida in the United States has steadily declined since the late 1960s. During this time, the ability to diagnose these defects prenatally has progressed rapidly. Many U.S. birth defects surveillance systems ascertain defects only among live-born infants or among infants and fetuses beyond a certain gestational age, thus excluding defects among pregnancies prenatally diagnosed as being affected by a neural tube defect (NTD) and electively terminated before the gestational age limit. The impact of prenatal diagnosis and subsequent pregnancy termination on the reported prevalence of anencephaly and spina bifida in the United States has not been well established. However, assessment of this impact is crucial to the use of surveillance data to monitor trends in the occurrence of NTDs and the effectiveness of interventions for these defects (e.g., increased consumption of folic acid).
Fetal diagnosis and therapy, 2015
Considering the lack of accurate and up-to-date information available about neural tube defects (NTDs) in France, the purpose of this study was to review clinical and epidemiological data of NTDs and to evaluate the current efficiency of prenatal diagnosis in Alsace (northeastern France). A population-based retrospective study was performed from data of the Registry of Congenital Malformations of Alsace between 1995 and 2009. Data were analyzed as a whole and according to the anatomical type of the malformation (anencephaly, cephalocele and spina bifida). Statistical analyses were carried out using the Statistical Package for the Social Sciences. 272 NTDs were recorded divided in 113 cases of anencephaly (42%), 35 cases of cephalocele (13%) and 124 cases of spina bifida (45%). The total prevalence at birth of 14/10,000 (95% CI 13-16) was stable throughout the reporting period. A chromosome abnormality was identified in 27 cases (12% of all karyotyped cases). NTDs were prenatally dia...
Neural tube defects, maternal cohorts, and age: a pointer to aetiology
Archives of Disease in Childhood, 1991
The effects of maternal year of birth and age on the declining prevalence of neural tube defects after 1972-3 were examined using 403 cases ascertained in a prospective study in the Fylde of Lancashire during 1957-89. Matched case-control data were analysed using conditional logistic regression analysis.
High incidence of neural tube defects in Bursa, Turkey
Paediatric and Perinatal Epidemiology, 1988
Summary. A radiological survey of 1204 members of the population of Bursa revealed a high prevalence of spina bifida occulta (16.3%). Hospital deliveries in the area also showed a high incidence of anencephalus and spina bifida aperta (5.8 per 1000 total births) in the years 1983 to 1986. In the first 6 months of 1987, however, there was an increase in incidence to 20 per 1000 births (P<0.01). The possibility is raised that the Chernobyl disaster of May 1986 might have resulted in the elevation of the rate in an already susceptible population.
Prevalence of anencephaly associated anomalies
IP Innovative Publication Pvt. Ltd., 2018
Introduction: Defective closure of rostral pore of neural tube leads to anencephaly. Folic acid deficiency is most common cause anencephaly. In most of the cases of Anencephaly is associated with other systemic anomalies. Objectives: Aim of present study was to find out the incidence of anencephaly associated systemic anomalies and their correlation with maternal age, sex of the foetus. Materials and Methods: 32 anencephaly foetuses obtained from the Department of obstetrics and gynaecology Navodaya Medical College. The period of study was from January 2013 to December 2016. Results: Out of 32 cases, 25(78.12%) cases showed presence of systemic anomalies associated with anencephaly, 53.12% of the cases were observed in primigravida. Most common associated anomaly was spinabifida 28.12% followed by gastrointestinal anomalies 6.25%. Conclusion: Incidence of anencephaly associated anomalies is not uncommon; hence gross systemic examination of the anencephalic abortus is required to find out incidence of anencephaly associated anomalies. Keywords: Anencephaly, Craniospinal rachinoschisis, Exomphalos, Spina bifida.