ABSTRACT
The German Twin Family Panel (TwinLife) is a German longitudinal study of monozygotic and dizygotic same-sex twin pairs and their families that was designed to investigate the development of social inequalities over the life course. The study covers an observation period from approximately 2014 to 2023. The target population of the sample are reared-together twins of four different age cohorts that were born in 2009/2010 (cohort 1), in 2003/2004 (cohort 2), in 1997/1998 (cohort 3) and between 1990 and 1993 (cohort 4). In the first wave, the study included data on 4097 twin families. Families were recruited in all parts of Germany so that the sample comprises the whole range of the educational, occupational and income structure. As of 2019, two face-to-face, at-home interviews and two telephone interviews have been conducted. Data from the first home and telephone interviews are already available free of charge as a scientific use-file from the GESIS data archive. This report aims to provide an overview of the study sample and design as well as constructs that are unique in TwinLife in comparison with previous twin studies - such as an assessment of cognitive abilities or information based on the children's medical records and report cards. In addition, major findings based on the data already released are displayed, and future directions of the study are presented and discussed.
Subject(s)
Cognition , Diseases in Twins/epidemiology , Educational Status , Registries/statistics & numerical data , Twins, Dizygotic/genetics , Twins, Monozygotic/genetics , Adolescent , Adult , Child , Child, Preschool , Diseases in Twins/genetics , Female , Germany/epidemiology , Humans , Incidence , Longitudinal Studies , Male , Young AdultABSTRACT
BACKGROUND: Real-time three-dimensional echocardiography (RT3DE) is a promising method for accurate assessment of left ventricular (LV) volumes and function, however, pediatric reference values are scarce. The aim of the study was to establish pediatric percentiles in a large population and to compare the inherent influence of different evaluation software on the resulting measurements. METHODS: In a multicenter prospective-design study, 497 healthy children (ages 1 day to 219 months) underwent RT3DE imaging of the LV (ie33, Philips, Andover, MA). Volume analysis was performed using QLab 9.0 (Philips) and TomTec 4DLV2.7 (vendor-independent; testing high (TomTec75) and low (TomTec30) contour-finding activity). Reference percentiles were computed using Cole's LMS method. In 22 subjects, cardiovascular magnetic resonance imaging (CMR) was used as the reference. RESULTS: A total of 370/497 (74.4%) of the subjects provided adequate data sets. LV volumes had a significant association with age, body size, and gender; therefore, sex-specific percentiles were indexed to body surface area. Intra- and interobserver variability for both workstations was good (relative bias ± SD for end-diastolic volume [EDV] in %: intraobserver: QLab = -0.8 ± 2.4; TomTec30 = -0.7 ± 7.2; TomTec75 = -1.9 ± 6.7; interobserver: QLab = 2.4 ± 7.5; TomTec30 = 1.2 ± 5.1; TomTec75 = 1.3 ± 4.5). Intervendor agreement between QLab and TomTec30 showed larger bias and wider limits of agreement (bias: QLab vs TomTec30: end-systolic volume [ESV] = 0.8% ± 23.6%; EDV = -2.2% ± 17.0%) with notable individual differences in small children. QLab and TomTec underestimated CMR values, with the highest agreement between CMR and QLab. CONCLUSIONS: RT3DE allows reproducible noninvasive assessment of LV volumes and function. However, intertechnique variability is relevant. Therefore, our software-specific percentiles, based on a large pediatric population, serve as a reference for both commonly used quantification programs.
Subject(s)
Algorithms , Echocardiography, Three-Dimensional/methods , Heart Ventricles/diagnostic imaging , Stroke Volume/physiology , Ventricular Function, Left/physiology , Adolescent , Child , Child, Preschool , Female , Follow-Up Studies , Humans , Infant , Infant, Newborn , Magnetic Resonance Imaging, Cine , Male , Prospective Studies , ROC Curve , Reference Values , Reproducibility of ResultsABSTRACT
The German twin family study 'TwinLife' was designed to enhance our understanding of the development of social inequalities over the life course. The interdisciplinary project investigates mechanisms of social inequalities across the lifespan by taking into account psychological as well as social mechanisms, and their genetic origin as well as the interaction and covariation between these factors. Main characteristics of the study are: (1) a multidimensional perspective on social inequalities, (2) the assessment of developmental trajectories in childhood, adolescence, and young adulthood in a longitudinal design by using (3) a combination of a multi-cohort cross-sequential and an extended twin family design, while (4) capturing a large variation of behavioral and environmental factors in a representative sample of about 4,000 German twin families. In the present article, we first introduce the theoretical and empirical background of the TwinLife study, and second, describe the design, content, and implementation of TwinLife. Since the data will be made available as scientific use file, we also illustrate research possibilities provided by this project to the scientific community.
