63 research outputs found
Pregnancy Recruitment for Population Research: the National Children's Study Vanguard Experience in W ayne C ounty, M ichigan
Background To obtain a probability sample of pregnancies, the N ational C hildren's S tudy conducted doorâtoâdoor recruitment in randomly selected neighbourhoods in randomly selected counties in 2009â10. In 2011, an experiment was conducted in 10 US counties, in which the twoâstage geographic sample was maintained, but participants were recruited in prenatal care provider offices. We describe our experience recruiting pregnant women this way in W ayne C ounty, M ichigan, a county where geographically eligible women attended 147 prenatal care settings, and comprised just 2% of total county pregnancies. Methods After screening for address eligibility in prenatal care offices, we used a threeâpart recruitment process: (1) providers obtained permission for us to contact eligible patients, (2) clinical research staff described the study to women in clinical settings, and (3) survey research staff visited the home to consent and interview eligible women. Results We screened 34â065 addresses in 67 provider settings to find 215 eligible women. Providers obtained permission for research contact from 81.4% of eligible women, of whom 92.5% agreed to a home visit. All homeâvisited women consented, giving a net enrolment of 75%. From birth certificates, we estimate that 30% of eligible county pregnancies were enrolled, reaching 40â50% in the final recruitment months. Conclusions We recruited a high fraction of pregnancies identified in a broad crossâsection of provider offices. Nonetheless, because of time and resource constraints, we could enrol only a fraction of geographically eligible pregnancies. Our experience suggests that the probability sampling of pregnancies for research could be more efficiently achieved through sampling of providers rather than households.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97525/1/ppe12047.pd
Lawson criterion for ignition exceeded in an inertial fusion experiment
For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37Â MJ of fusion for 1.92Â MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers âŒ99% of the euchromatic genome and is accurate to an error rate of âŒ1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Population-based analysis of survival for hypoplastic left heart syndrome
Objective: To analyze survival patterns among infants with hypoplastic left heart syndrome (HLHS) in the State of Michigan. Study design: Cases of HLHS prevalent at live birth were identified and confirmed within the Michigan Birth Defects Registry from 1992 to 2005 (n = 406). Characteristics of infants with HLHS were compared with a 10:1 random control sample. Results: Compared with 4060 control subjects, the 406 cases of HLHS were more frequently male (62.6% vs 51.4%), born prematurely (\u3c37 weeks gestation; 15.3% vs 8.7%), and born at low birth weight (LBW) (\u3c2.5 kg; 16.0% vs 6.6%). HLHS 1-year survival rate improved over the study period (P = .041). Chromosomal abnormalities, LBW, premature birth, and living in a high poverty neighborhood were significantly associated with death. Controlling for neighborhood poverty, term infants versus preterm with HLHS or LBW were 3.2 times (95% CI: 1.9-5.3; P \u3c .001) more likely to survive at least 1 year. Controlling for age and weight, infants from low-poverty versus high-poverty areas were 1.8 times (95% CI: 1.1-2.8; P = .015) more likely to survive at least 1 year. Conclusions: Among infants with HLHS in Michigan, those who were premature, LBW, had chromosomal abnormalities, or lived in a high-poverty area were at increased risk for early death. Copyright © 2011 Mosby Inc. All rights reserved
Prevalence of Selected Birth Defects by Maternal Nativity Status, United States, 1999â2007
Objectives: We investigated differences in prevalence of major birth defects by maternal nativity within racial/ethnic groups for 27 major birth defects.
Methods: Data from 11 population-based birth defects surveillance systems in the United States including almost 13 million live births (approximately a third of U.S. births) during 1999â2007 were pooled. We calculated prevalence estimates for each birth defect for five racial/ethnic groups. Using Poisson regression, crude and adjusted prevalence ratios (aPRs) were also calculated using births to US-born mothers as the referent group in each racial/ethnic group.
Results: Approximately 20% of case mothers and 26% of all mothers were foreign-born. Elevated aPRs for infants with foreign-born mothers were found for spina bifida and trisomy 13, 18, and 21, while lower prevalence patterns were found for pyloric stenosis, gastroschisis, and hypospadias.
Conclusions: This study demonstrates that birth defects prevalence varies by nativity within race/ethnic groups, with elevated prevalence ratios for some specific conditions and lower prevalence for others. More detailed analyses focusing on a broader range of maternal behaviors and characteristics are required to fully understand the implications of our findings
Birth Defect Survival for Hispanic Subgroups
Background: Previous studies demonstrate that infant and childhood mortality differ among children with birth defects by maternal race/ethnicity, but limited mortality information is published for Hispanic ethnic subgroups.
Methods: We performed a retrospective cohort study using data for children with birth defects born to Hispanic mothers during 1999â2007 from 12 population-based state birth defects surveillance programs. Deaths were ascertained through multiple sources. Survival probabilities were estimated by the Kaplan-Meier method. Cox proportional hazards regression was used to examine the effect of clinical and demographic factors on mortality risk.
Results: Among 28,497 Hispanic infants and children with major birth defects, 1-year survival was highest for infants born to Cuban mothers at 94.6% (95% confidence intervals [CI] 92.7â96.0) and the lowest for Mexicans at 90.2% (95% CI 89.7â90.6; pâ\u3câ.0001). For children aged up to 8 years, survival remained highest for Cuban Americans at 94.1% (95% CI 91.8â95.7) and lowest for Mexican Americans at 89.2% (95% CI 88.7â89.7; pâ=â.0002). In the multivariable analysis using non-Hispanic White as the reference group, only infants and children born to Mexican mothers were noted to have a higher risk of mortality for cardiovascular defects.
Conclusions: This analysis provides a better understanding of survival and mortality for Hispanic infants and children with selected birth defects. The differences found in survival, particularly the highest survival rates for Cuban American children and lowest for Mexican American children with birth defects, underscores the importance of assessing Hispanic ethnic subgroups, as differences among subgroups appear to exist
Population-Based Microcephaly Surveillance in the United States, 2009 to 2013: An Analysis of Potential Sources of Variation
Background: Congenital microcephaly has been linked to maternal Zika virus infection. However, ascertaining infants diagnosed with microcephaly can be challenging.
Methods: Thirty birth defects surveillance programs provided data on infants diagnosed with microcephaly born 2009 to 2013. The pooled prevalence of microcephaly per 10,000 live births was estimated overall and by maternal/infant characteristics. Variation in prevalence was examined across case finding methods. Nine programs provided data on head circumference and conditions potentially contributing to microcephaly.
Results: The pooled prevalence of microcephaly was 8.7 per 10,000 live births. Median prevalence (per 10,000 live births) was similar among programs using active (6.7) and passive (6.6) methods; the interdecile range of prevalence estimates was wider among programs using passive methods for all race/ethnicity categories except Hispanic. Prevalence (per 10,000 live births) was lowest among non-Hispanic Whites (6.5) and highest among non- Hispanic Blacks and Hispanics (11.2 and 11.9, respectively); estimates followed a U-shaped distribution by maternal age with the highest prevalence among mothers \u3c20 years (11.5) and \u3e/= 40 years (13.2). For gestational age and birth weight, the highest prevalence was among infants varied; 41.8% of cases had an HC \u3e/= the 10th percentile for sex and gestational age.
Conclusion: Differences in methods, population distribution of maternal/infant characteristics, and case definitions for microcephaly can contribute to the wide range of observed prevalence estimates across individual birth defects surveillance programs. Addressing these factors in the setting of Zika virus infection can improve the quality of prevalence estimates
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