In the last two to three decades, increasing rates of gastroschisis but not of omphalocele have been reported from different parts of the world. The present study represents a register containing 469 children born with abdominal wall defects based on data retrieved from 20 birth cohorts (1970-89) in three nationwide registries. A tentative estimate of the completeness as regards identification of liveborn and stillborn infants is a minimum of 95% and 90% respectively. All cases were reclassified to 166 cases of gastroschisis, 258 of omphalocele and 16 of gross abdominal wall defect. The average point prevalence at birth of gastroschisis was 1.33 per 10 000 live and stillbirths. During the first decade, an increase in prevalence occurred culminating in 1976, followed by a decrease reaching its initial value in 1983 and then a new increase. Overall, no significant linear trend could be demonstrated for the entire period. The average point prevalence at birth for omphalocele was 2.07 and for gross abdominal wall defect 0.12 per 10 000 live and stillbirths with no significant change in the period. The geographical distribution of gastroschisis and omphalocele showed no difference per county.
OBJECTIVE: To determine the accuracy of maternal recall of children birthweight (BW) and gestational age (GA), using the Danish Medical Birth Register (DBR) as reference and to examine the reliability of recalled BW and its potential correlates. DESIGN: Comparison of data from the DBR and the European Youth Heart Study (EYHS). SETTING: Schools in Odense, Denmark. POPULATION: A total of 1271 and 678 mothers of school children participated with information in the accuracy studies of BW and GA, respectively. The reliability sample of BW was composed of 359 women. METHOD: The agreement between the two sources was evaluated by mean differences (MD), intraclass correlation coefficient (ICC) and Bland-Altman's plots. The misclassification of the various BW and GA categories were also estimated. MAIN OUTCOME MEASURES: Differences between recalled and registered BW and GA. RESULTS: There was high agreement between recalled and registered BW (MD =-0.2 g; ICC = 0.94) and GA (MD = 0.3 weeks; ICC = 0.76). Only 1.6% of BW would have been misclassified into low, normal or high BW and 16.5% of GA would have been misclassified into preterm, term or post-term based on maternal recall. The logistic regression revealed that the most important variables in the discordance between recalled and registered BW were ethnicity and parity. Maternal recall of BW was highly reliable (MD =-5.5 g; ICC = 0.93), and reliability remained high across subgroups. CONCLUSION: Maternal recall of BW and GA seems to be sufficiently accurate for clinical and epidemiological use.
In the present study, we evaluated whether childhood differences in body height between singletons and twins persist into adulthood. Data from the Medical Birth Register of Norway were linked with data from the Norwegian National Conscript Service. This study used data on the 457,999 males who were born alive and without physical anomalies in single or twin births in Norway during 1967-1984 and who were examined at the mandatory military conscription (age 18-20 years; 1985-2003). For sibling comparisons, the authors selected the 1,721 sibships of full brothers that included at least 1 male born in a single birth and at least 1 male born in a twin birth (4,520 persons, including 2,493 twins and 2,027 singletons). An analysis of the total study population using generalized estimating equations showed that the twins were 0.6 cm (95% confidence interval: 0.4, 0.7) shorter than were the singletons after adjustment for a series of background factors. The fixed-effects regression analysis of the sibships that included both twins and singletons showed that the twins were 0.9 cm (95% confidence interval: 0.6, 1.2) shorter than were their singleton brothers. The study suggests that male twins born in Norway during 1967-1984 were slightly shorter in early adulthood than were singletons.
Advanced maternal age at birth is considered a major risk factor for birth outcomes. It is unclear to what extent this association is confounded by maternal characteristics. To test whether advanced maternal age at birth independently increases the risk of low birth weight (
Gestational age estimation by last menstrual period (LMP) vs. ultrasound (or best obstetric estimate in the US) may result in discrepant classification of preterm vs. term birth. We investigated whether such discrepancies are associated with adverse infant outcomes.
We studied singleton livebirths in the Medical Birth Registries of Norway, Sweden and Finland and US live birth certificates from 1999 to the most recent year available. Risk ratios (RR) with 95% confidence intervals (CI) by discordant and concordant gestational age estimation for infant, neonatal and post-neonatal mortality, Apgar score
Data from the Medical Birth Registry of Norway were used to estimate sibship correlations in large sibships (each with > or = 5 infants among singleton live births surviving the first year of life), while adjusting for covariates such as infant gender, gestational age, maternal age, parity, and time since last pregnancy. This sample of 12,356 full sibs in 2,462 sibships born in Norway between 1968 and 1989 was selected to maximize the information on parity, and a robust approach to estimating both regression coefficients and the sibship correlation using generalized estimating equations (GEE) was employed. In concordance with previous studies, these data showed a high overall correlation in birth weight among full sibs (0.48 +/- 0.01), but this sibship correlation was influenced by parity. In particular, the correlation between the firstborn infant and a subsequent infant was slightly lower than between two subsequent sibs (0.44 +/- 0.01 vs. 0.50 +/- 0.01, respectively). The effect of time between pregnancies was statistically significant, but its predicted impact was modest over the period in which most of these large families were completed. While these data cannot discriminate whether factors influencing birth weight are maternal or fetal in nature, this analysis does illustrate how robust statistical models can be used to estimate sibship correlations while adjusting for covariates in family studies.
We assessed the linkage and correct linkage rate using deterministic record linkage among three commonly used Canadian databases, namely, the population registry, hospital discharge data and Vital Statistics registry.
Three combinations of four personal identifiers (surname, first name, sex and date of birth) were used to determine the optimal combination. The correct linkage rate was assessed using a unique personal health number available in all three databases.
Among the three combinations, the combination of surname, sex, and date of birth had the highest linkage rate of 88.0% and 93.1%, and the second highest correct linkage rate of 96.9% and 98.9% between the population registry and Vital Statistics registry, and between the hospital discharge data and Vital Statistics registry in 2001, respectively. Adding the first name to the combination of the three identifiers above increased correct linkage by less than 1%, but at the cost of lowering the linkage rate almost by 10%.
Our findings suggest that the combination of surname, sex and date of birth appears to be optimal using deterministic linkage. The linkage and correct linkage rates appear to vary by age and the type of database, but not by sex.
Cites: Aust N Z J Public Health. 2002;26(3):251-512141621
Cites: Comput Biol Med. 1983;13(3):157-696617166
Cites: Comput Biol Med. 1986;16(1):45-573948494
Cites: Int J Epidemiol. 1990 Sep;19(3):553-82262247
BACKGROUND: Low birth weight has been associated with an increased risk of type 2 diabetes in adulthood. Poor fetal nutrition has been suggested to explain this association. Our objective was to determine whether genetic factors contribute to the association between low birth weight and subsequent risk of type 2 diabetes. METHODS: We retrieved information from original birth records on same-sex Swedish twins with known zygosity, born from 1926 to 1958. We used regression models to investigate whether birth weight was associated with risk of type 2 diabetes in the cohort of twins overall, and in case-control analyses within disease-discordant dizygotic and monozygotic twin pairs. RESULTS: Of 18,230 twins, 592 (3.2%) had type 2 diabetes. The rate of type 2 diabetes consistently increased with decreasing birth weight, from 2.4% among twins with birth weights of 3500 g or more to 5.3% among those with birth weights less than 2000 g. In the cohort analysis, in which twins are analyzed as independent individuals, the adjusted odds ratio (95% confidence interval) of type 2 diabetes per 500-g decrease in birth weight was 1.44 (1.28-1.63). When we compared the diseased twin with the healthy cotwin, the corresponding odds ratios were 1.38 (1.02-1.85), among dizygotic twins, and 1.02 (0.63-1.64), among monozygotic twins. CONCLUSIONS: Low birth weight is associated with type 2 diabetes in adulthood. The difference in this association between monozygotic and dizygotic twin pairs suggests that genetic mechanisms play an important role in this association.