The paper describes associated malformations in infants born with neural tube defects (N = 3,809) from three large malformation registers and in fetuses aborted because of a diagnosed neural tube defect (N = 748) from two of the registers. In infants, upper spina bifida and encephalocele are more often associated with non-neural malformations than anencephaly or lower spina bifida. Aborted fetuses with spina bifida or encephalocele have associated malformations registered more often than infants with those neural tube defects, but the opposite is true for anencephaly. The degree of detail of the investigation of an aborted specimen or a perinatally dead infant will contribute to such differences but they can also depend on the fact that prenatal detection may be facilitated by the simultaneous presence of other malformations like body wall defects. Also, fetuses with many malformations may be more prone to abort spontaneously late in pregnancy. Variable prenatal diagnosis may, therefore, explain population differences in the pattern of associated malformations. The type of associated malformation differs with the level of the neural tube defect: this could be due to different causal mechanisms or be a question of cranio-caudal level and/or timing. For limb reduction defects, however, we did not find any association between upper limb and upper neural tube defects or lower limb and lower neural tube defects. These findings together with other epidemiological data support the idea that upper and lower neural tube defects may have different significance in epidemiological studies and should be treated separately.
BACKGROUND: In 1999, concerns were raised that vaccines containing the preservative Thimerosal might increase the risk of autism and/or other neurodevelopmental disorders. METHODS: Between the mid-1980s through the late-1990s, we compared the prevalence/incidence of autism in California, Sweden, and Denmark with average exposures to Thimerosal-containing vaccines. Graphic ecologic analyses were used to examine population-based data from the United States (national immunization coverage surveys and counts of children diagnosed with autism-like disorders seeking special education services in California); Sweden (national inpatient data on autism cases, national vaccination coverage levels, and information on use of all vaccines and vaccine-specific amounts of Thimerosal); and Denmark (national registry of inpatient/outpatient-diagnosed autism cases, national vaccination coverage levels, and information on use of all vaccines and vaccine-specific amounts of Thimerosal). RESULTS: In all three countries, the incidence and prevalence of autism-like disorders began to rise in the 1985-1989 period, and the rate of increase accelerated in the early 1990s. However, in contrast to the situation in the United States, where the average Thimerosal dose from vaccines increased throughout the 1990s, Thimerosal exposures from vaccines in both Sweden and Denmark-already low throughout the 1970s and 1980s-began to decrease in the late 1980s and were eliminated in the early 1990s. CONCLUSIONS: The body of existing data, including the ecologic data presented herein, is not consistent with the hypothesis that increased exposure to Thimerosal-containing vaccines is responsible for the apparent increase in the rates of autism in young children being observed worldwide.
Comment In: Am J Prev Med. 2004 Jan;26(1):91; reply 91-214700719
BACKGROUND & AIMS: Estimates of the frequency of hereditary nonpolyposis colon cancer (HNPCC) based on clinical criteria have varied widely. Recent studies of germline mismatch repair gene mutations have suggested that HNPCC accounts for close to 3% of all colon cancer, but this estimate may have been inflated by inclusion of founder effects peculiar to Finland. We therefore determined by genetic criteria the colon cancer burden associated with HNPCC in a population-based study of 1066 individuals from Utah and California. METHODS: The coding regions of mismatch repair genes hMSH2 and hMLH1 were sequenced from the germline of those individuals whose tumors exhibited microsatellite instability. RESULTS: Microsatellite instability was present in 16% (171/1066) of tumors. Pathogenic germline mismatch repair gene mutations were identified in 7 individuals, and missense amino acid changes of uncertain significance were identified in another 6 individuals. After adjusting for the availability of sufficient germline DNA for sequencing, the 7 clearly pathogenic mutations accounted for 0.86% of colon cancer at the population level. Individuals with these mutations were significantly younger, more likely to have a family history of colon and endometrial cancer, and more likely to have first-degree relatives with a young-age onset of colon cancer than individuals with unstable tumors but without germline mutations (P
Cross-Country Individual Participant Analysis of 4.1 Million Singleton Births in 5 Countries with Very High Human Development Index Confirms Known Associations but Provides No Biologic Explanation for 2/3 of All Preterm Births.
Preterm birth is the most common single cause of perinatal and infant mortality, affecting 15 million infants worldwide each year with global rates increasing. Understanding of risk factors remains poor, and preventive interventions have only limited benefit. Large differences exist in preterm birth rates across high income countries. We hypothesized that understanding the basis for these wide variations could lead to interventions that reduce preterm birth incidence in countries with high rates. We thus sought to assess the contributions of known risk factors for both spontaneous and provider-initiated preterm birth in selected high income countries, estimating also the potential impact of successful interventions due to advances in research, policy and public health, or clinical practice.
We analyzed individual patient-level data on 4.1 million singleton pregnancies from four countries with very high human development index (Czech Republic, New Zealand, Slovenia, Sweden) and one comparator U.S. state (California) to determine the specific contribution (adjusting for confounding effects) of 21 factors. Both individual and population-attributable preterm birth risks were determined, as were contributors to cross-country differences. We also assessed the ability to predict preterm birth given various sets of known risk factors.
Previous preterm birth and preeclampsia were the strongest individual risk factors of preterm birth in all datasets, with odds ratios of 4.6-6.0 and 2.8-5.7, respectively, for individual women having those characteristics. In contrast, on a population basis, nulliparity and male sex were the two risk factors with the highest impact on preterm birth rates, accounting for 25-50% and 11-16% of excess population attributable risk, respectively (p
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A study has been made on certain epidemiological characteristics of infants with alimentary tract atresia: esophageal atresia, small and large gut atresia, and anal atresia. Data were collected from three malformation registries and represent a material of more than 4.5 million births. A total of 3,550 infants with alimentary atresia were identified corresponding to a total rate of about 8 per 10,000 births. In 167 infants (4.7%) more than one of the major atresia types were present simultaneously. Racial differences were found (based on data from California) for esophageal atresia where whites had a higher rate than other races. For gastrointestinal atresia, a high rate in blacks was found, while no differences between races were seen for anal atresia. Also, differences in registered rates between the three programs were found, at least partly explainable by different ascertainment. The different forms of atresia were compared from the point of view of sex ratio, twinning rate, maternal age and parity distribution, presence of chromosome anomalies, and types of associated malformations. The pathogenesis and etiology of the various types of atresia are discussed based on these observations. The conclusion is that although undoubtedly other pathogenetic mechanisms may exist for gastrointestinal atresia, a substantial proportion of all infants with alimentary atresia had their malformations as a result of early disturbances of intestinal morphogenesis. Within each subgroup, apparently different etiologies may exist, resulting in differences in epidemiological characteristics.
BACKGROUND: Anophthalmia and microphthalmia are serious eye malformations which recently have been associated with exposure to Benomyl. Data on these malformations are scarce in the literature and reported prevalences at birth vary strongly. METHODS: Data from three large registers of congenital malformations were analysed and comprised 849 malformed infants based on close to 5.7 million births. RESULTS: This is the largest available epidemiological study on anophthalmia and microphthalmia. The prevalence at birth was 1.50 per 10,000, varying between 0.92 and 2.29 between registers but no varying significantly between races in the California register. The variation in rates was mainly due to different inclusion of chromosomally abnormal infants (mainly trisomy 13) and of infants with microphthalmia occurring with major non-eye malformations. On the other hand, rates of anophthalmia and isolated microphthalmia were similar. Other major non-eye malformations were found in 73% of infants without a known chromosome anomaly. The malformation was bilateral in 53-60% of infants except when microphthalmia existed without any other malformations when only 27% were bilateral. Sex distribution was normal, there was a slight excess of twins, and an increased risk at high maternal age. CONCLUSIONS: In analytical studies searching for the cause of these malformations, it may be useful to restrict the analysis to infants with anophthalmia or isolated microphthalmia as the recording of such cases seems to be more reliable than of microphthalmia occurring with other malformations. The conclusions presented in the literature on the possible effect of Benomyl are partly based on data with apparent very incomplete ascertainment.
Infants with kidney agenesis or dysgenesis, infants with cystic kidneys, and infants with horseshoe kidneys were studied, based on data from three large and population-based congenital malformation registers: a total of 2666 infants among 5.83 million births. There is a strong variability between programs of the rates of registered unilateral kidney malformations and these are strongly over-represented in dead infants or infants with other malformations. There is a male excess but this varies in strength between different types of kidney malformations and between bilateral and unilateral forms. An increased twinning rate was found. The different types of kidney malformation differed with respect to kind of associated non-urological malformations in multimalformed infants. We conclude that for monitoring purposes one should restrict analysis to bilateral forms but that unilateral forms can be of interest in epidemiological analyses.
There were three objectives of this study: to investigate possible specificity in the association between specific cardiac defects and chromosomal anomalies; to evaluate ways of categorizing cardiac defects into larger groups with epidemiological similarities that could indicate similarities in etiology or pathogenesis; and to analyze the relationship between specific cardiac defects and diabetes. We pooled data on infants (aged 1 year or younger) with congenital cardiovascular defects from three large birth defect registries in California, Sweden, and France. The registries in Sweden and France obtained data through reporting from various sources; in California, medical records were reviewed. For severe congenital heart defects, the percentage of infants with identified chromosomal anomalies varied between 0.9% for d-TGV to 68.4% for ECD. In general, specific cardiac conditions have different risk factors. For example, conotruncal defects have been traditionally grouped, but the data presented in this paper indicates more differences for risk factors for the components of conotruncal defects: tetralogy of Fallot, d-TGV, common truncus, and DORV. In general, we suggest the strategy of "splitting" rather than "lumping" when searching for specific genetic factors and/or teratogens. Adequate analysis thus requires large registries or collaboration among registries. The findings did not support constellations between mothers' diabetes and specific defects.
To analyze complex and noncomplex cardiac malformations regarding prevalence and in relation to demographic variables, we pooled data on infants (age 1 year or younger) with congenital cardiovascular defects from three large birth defect registries in California, Sweden, and France. Altogether, 12,932 infants had one or more congenital heart defects out of 4.4 million live births and stillbirths. The registries in Sweden and France obtained data through reporting from various sources; in California, medical records were reviewed. As expected, definitions and ascertained conditions differed among each of the registries. The total rates for severe defects were similar (1.43 per 1,000), but differed for specific defects. Clear differences in epidemiological characteristics existed for specific defects; for example, severe cardiac defects sex ratios were significantly high for hypoplastic left heart syndrome, d-transposition of great vessels, double outlet right ventricle, total anoralous pulmonary venous return, tetralogy of Fallot, and significantly low for pulmonary atresia without ventricular septal defect and endocardial cushion defect. Few defects were similar for several epidemiological characteristics, but, for example, the combination of ventricular and atrial septal defects appeared equivalent with endocardial cushion defect under some circumstances, yet behaved differently with regard to associated noncardiovascular defects.
OBJECTIVE: To present epidemiologic data on the relatively rare malformation choanal atresia, based on a large collection of material and with special stress on the significance of the so-called CHARGE (coloboma, heart defect, choanal atresia, retarded growth and development, genital anomaly, and ear defect with deafness) association. METHODS: Data from three large registries of congenital malformations were used. Based on more than 5 million births, 444 infants with choanal atresia were identified. RESULTS: The average rate of choanal atresia is 0.82 per 10,000 and varies among programs. There is no statistically significant difference between races in rates, even though white infants have a higher rate than those of other races. The higher rate found in the California program is mainly attributable to unilateral, isolated cases. Unilateral atresia occurs equally often on the right and left. Among all cases of choanal atresia, the sex distribution is normal, a slightly increased risk at twinning exists, and no effect of maternal age or parity is seen. Chromosome anomalies are found in 6% of infants with choanal atresia, and 21 infants (5%) have monogenic syndromes or conditions. An analysis of associated malformations (present in 47% of the infants without chromosome anomalies) indicated that although a weak nonrandom association can be demonstrated between the malformations entering the so-called CHARGE complex, only a small proportion of infants with choanal atresia and other components of that condition probably represent this entity. The term CHARGE association seems to be overused in clinical practice. CONCLUSION: To be meaningful, the term CHARGE should be restricted to infants with multiple malformations and choanal atresia and/or coloboma combined with other cardinal malformations (heart, ear, and genital) and with a total of at least three cardinal malformations. Growth retardation should not be used in the definition.