Effect of maternal and infant covariates on sibship correlation in birth weight

Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.     

Partner- and partnership-related risk factors for preterm birth among low-income women in Lima,Peru

A woman's partner and the characteristics of their partnership can play an important role in the health of her pregnancy. Yet, with the notable exception of intimate partner violence, there has been little previous research addressing the associations between partner- or partnership-related factors and birth outcomes. This analysis tested the hypothesis that risk factors related specifically to partner or partnership characteristics increased the risk for preterm birth. Between 2003 and 2005, a total of 580 preterm cases (20–36 weeks gestational age at delivery) and 633 term controls (≥37 weeks) were selected from women delivering at an obstetric hospital in Lima, Peru. Each woman completed a confidential, structured interview and provided biological specimens within 48 h after delivery. Multivariable logistic regression was used to assess associations between partner and partnership characteristics and preterm birth. After adjustment for behavioral, demographic, and obstetric risk factors, ever having had a partner with a history of drug use (aOR = 1.91, 95% CI 1.22–2.99), ever having had anal sex (aOR = 1.40, 95% CI 1.07–1.84), having a current partner with a history of visiting prostitutes (aOR = 1.69, 95% CI 1.22–2.33), and perceiving one's current partner as a “womanizer” (aOR = 1.34, 95% CI 1.02–1.77) were significantly associated with an elevated risk of preterm birth when tested in separate models. These four factors were then used to create a composite partnership risk score, which showed an increasing dose-response relationship with preterm birth risk (per additional partner risk factor: aOR = 1.31, 95% CI 1.16–1.49). These results highlight the importance of considering a broader set of risk factors for preterm birth, specifically those related to a woman's partner and partnership characteristics. Further research could clarify the specific mechanisms through which these partner and partnership characteristics may increase the risk of preterm birth.     

新生儿出生信息样本分析

目的:了解和探讨新生儿出生信息的分布态势及规律。方法:对本院2006年1~6月间所有新生儿出生信息进行样本分析。结果:半年间分娩的新生儿共1075例,其中死亡19例,双胞胎15例,以1028例单胎活产新生儿的出生体重、胎龄及产妇年龄作为研究样本进行分析,统计数据与传统意义上的正常胎龄和新生儿体重基本相符,胎龄、体重均值均有所提高。结论:孕产妇的健康状况和新生儿的体质均有所改善,随胎龄的增加,新生儿出生体重亦随之增加,并且,目前新生儿的整体统计体重要大于现有的临床指标,因此,应对现有的临床指标进行适当调整,重新确定低出生体重儿和巨大儿的临床指标。     

Lung function development in the first 2 yr of life is independent of allergic diseases by 2 yr

The aim of the study was to assess if lung function at birth predicts lung function at 2 yr and secondly, if lung function development was influenced by the common phenotypes of recurrent bronchial obstruction (rBO) or atopic eczema (AE) by 2 yr. Lung function was assessed at birth (n = 802) and at 2 yr within the prospective birth cohort study 'the Environment and Childhood Asthma Study' in Oslo. The 135 children with lung function measured at birth by tidal flow volume (TFV) loops and passive respiratory mechanics, who were included in a nested case-control study were reinvestigated at 2 yr with clinical examination, TFV loops (n = 90) (mean age 26.6 (3.7 s.d.) months), skin prick test and parental interview. Children were categorized into quartiles (lower, middle two, upper) according to time to peak tidal expiratory flow/total expiratory time (t(PTEF)/t(E)) at birth as well as clinical phenotype based on the presence of rBO and/or AE (ever) by 2 yr. The observed reduction in mean t(PTEF)/t(E) from birth to 2 yr within the quartiles, were not significantly different after controlling for 'regression to the mean'. t(PTEF)/t(E) at birth correlated significantly with t(PTEF)/t(E) at 2 yr, (r = 0.475, p < 0.001). Children with both rBO and AE by 2 yr had significantly lower t(PTEF)/t(E) at 2 yr (p = 0.002) and at birth (p = 0.027), compared with children with no rBO or AE. Clinical phenotype at 2 yr did not influence the change in t(PTEF)/t(E) from birth to 2 yr. This study demonstrates a clear tracking of lung function from birth, not influenced by rBO or AE by 2 yr.     

How many subjects are needed in a longitudinal birth cohort study?

One of the first decisions that needs to be taken when planning a birth cohort concerns the size of the study. This in turn will depend on the research questions to be answered and thence whether environmental exposures and outcomes are measured on a continuum or as dichotomous variables. Here we describe ways in which different birth cohorts have addressed this issue and explore the advantages of smaller detailed studies over larger less-detailed studies.     

Transcatheter closure of the patent arterial duct using the Flipper coil in a premature infant weighing 1,400 g: a case report.

A symptomatic 1,400 g premature triplet underwent successful transcatheter coil embolization of patent arterial duct using the umbilical artery. One 3 mm x 3 cm Flipper coil was used with no angiographic residual shunt. To the best of our knowledge, this is one of the smallest preterm infants to undergo this transcatheter procedure.     

Early rapid weight gain and current overweight in relation to asthma in adolescents born with very low birth weight

Early catch-up growth and subsequent overweight are suggested to be associated with later cardiovascular diseases and later type II diabetes. However, the impact of early catch-up growth and childhood overweight on the development of asthma has been less studied, particularly in children born with very low birth weight (VLBW). A birth cohort of 74 VLBW children (birth weight < or = 1500 g) was followed from birth and investigated on asthma at 12 yr of age. Early rapid weight gain was in one way defined as an increase of weight > or =1 standard deviation score (SDS) at 6 months of corrected postnatal age. Current overweight was defined by body mass index (BMI) exceeding 21.2 and 21.7 kg/m(2), respectively, for boys and girls at 12 yr of age. Current asthma was diagnosed by a pediatrician, according to asthma ever in combination with a positive response to hypertonic saline bronchial provocation test and/or wheeze at physical examination at 12 yr old. Being overweight at 12 yr of age was associated with an increased risk for current asthma in the VLBW children [crude odds ratio (OR): 5.5, 95% confidence interval (CI): 1.3-22.2]. After adjustment for early weight gain and neonatal risk, the OR of overweight increased nearly three times (adjusted OR: 15.3, 95% CI: 2.5-90.6). Early rapid weight gain seemed to be inversely associated with current asthma (adjusted OR: 0.49 for an increase of weight equal to 1 SDS, 95% CI: 0.23-1.02, p = 0.06). In addition, early rapid weight gain was inversely associated with the magnitude of bronchial responsiveness at 12 yr (coefficient -1.15, p < 0.01). There was a strong and positive association between overweight and asthma at 12 yr of age in the VLBW children. This strong association had been reduced by early rapid weight gain, possibly via the reduction of bronchial responsiveness.     

Before-birth climatologic data may play a role in the development of allergies in infants

While an exacerbation in allergic symptoms corresponding to seasons has long been reported, few studies have investigated the association between the season of birth and allergic disorders. The aim of this study was to investigate whether the climatologic data before and after birth affected the incidence of atopic dermatitis (AD) and the results of allergy-related blood tests in early infancy. From February 1995 to January 2000, 2136 infants were tested for AD and followed for 12 months. AD patients were tested by using allergy-related blood tests. Data were compared according to the month of birth and the climatologic data using a computed statistical software package. Six hundred and thirty infants had AD before 12 months old, and significant differences were found according to the season of birth (p < 0.0001). Infants born in spring showed the lowest (22.3%) incidence, while those born in autumn showed the highest (34.6%). In 369 patients, total serum IgE levels, and serum specific IgE levels with egg white at 3 months old were also different according to the season of birth. All of these levels were lower in patients born in spring and summer, and higher in patients born in autumn and winter. Furthermore, the cumulative sunshine amount during the 3 months before and after birth was inversely correlated, while the average temperature over the 3 months before birth was positively correlated to the incidence of AD according to the month of birth. The climatologic data around birth may play an important role in whether an infant develops allergies.     

Adipokines in cord blood and risk of wheezing disorders within the first two years of life

BACKGROUND: Adipokines are involved in the regulation of many inflammatory processes and are present at very high concentrations in cord blood of term infants. OBJECTIVE: We analysed data of a large prospective birth cohort study to examine whether adiponectin and leptin concentration in cord blood are determinants of wheezing disorders in children within the first 2 years of life. METHODS: Seven hundred and forty mothers and their newborns were included in this analysis. Adiponectin and leptin concentrations were measured in cord blood. The cumulative incidence of physician-reported asthma or obstructive bronchitis was recorded during a 2-year follow-up. RESULTS: During the first 2 years of life, asthma or obstructive bronchitis was reported by the caring paediatricians for 157 (19.6%) of the children. We found a strong interaction of cord blood adiponectin and history of atopic disease in the mother with respect to the risk of physician-reported asthma or obstructive bronchitis (P=0.006). Compared with children with cord blood levels in the middle quintile (reference category), the odds ratios for physician-reported asthma or obstructive bronchitis in the bottom quintile and top quintile were 0.14 [95% confidence interval (CI) 0.02-0.90] and 2.12 (95% CI 0.67-6.66), respectively (P for trend=0.0003), among children of mothers with a history of atopy. This association was independent of other established risk factors. Leptin levels in cord blood were not associated with risk of asthma or obstructive bronchitis. CONCLUSIONS: In children of mothers with a history of atopy, concentrations of adiponectin in cord blood could play an important role in determining risk of wheezing disorders in early childhood.     

The complex enterprise of modelling prenatal exposure to cigarettes: what is ‘enough’?

While there is a burgeoning body of research linking smoking during pregnancy to problem behaviour in offspring, a major criticism of this work has been the crude measurement of exposure in these studies (e.g. retrospective, self-reported only) that could lead to biased estimates. To address this issue, we used a pregnancy cohort with repeated prospective measures of exposure as well as biological assays to generate estimates of exposure patterns using a range of modelling techniques. In this paper we report on the analytical approaches we have developed, including patterns of exposure over time and best-estimate approaches that combine self-report and cotinine measures, and compare their predictive value in relation to different dimensions of fetal growth as a first step towards examining the utility of greater precision of exposure measurement.
Surprisingly, in this sample the more complex assessments of exposure, including biological measures, generally did not perform better than simple indicators of exposure based on repeated self-report measures, with one exception: a combined self-report cotinine 'best estimate' of third trimester exposure was uniquely associated with lower brain : body ratio. Further study is needed using more sophisticated cotinine assays and testing prediction of a range of outcomes to ascertain whether these findings represent true differences or are specific to the sample, methods and outcomes used. Such research will inform the development of guidelines for adequate exposure characterisation in developmental studies.