The German Twin Family Panel (TwinLife).

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.

Genetic and environmental contributions to the subjective burden of social isolation during the COVID-19 pandemic.

BACKGROUND: Feelings of loneliness and the burden of social isolation were among the most striking consequences of widespread containment measures, such as "social distancing", during the COVID-19 pandemic. Because of the potential impact on people's health, there has been increased interest in understanding the mechanisms and factors that contributed to feelings of loneliness and the burdens of social isolation. However, in this context, genetic predisposition has been largely ignored as an important factor. This is problematic because some of the phenotypic associations observed to date may in fact be genetic. The aim of this study is, therefore, to examine the genetic and environmental contributions to the burden of social isolation at two time points during the pandemic. In addition, we examine whether risk factors identified in previous studies explain genetic or environmental contributions to the burden of social isolation. METHODS: The present study is based on a genetically sensitive design using data from the TwinLife panel study, which surveyed a large sample of adolescent and young adult twins during the first (N = 798) and the second (N = 2520) lockdown in Germany. RESULTS: We find no substantive differences in genetic and environmental contributions to social isolation burden over the course of the pandemic. However, we find the determinants highlighted as important in previous studies can explain only a small proportion of the observed variance in the burden of social isolation and mainly explained genetic contributions. CONCLUSIONS: While some of the observed associations appear to be genetic, our findings underscore the need for further research, as the causes of individual differences in burden of social isolation remain unclear.

Mode of birth and social inequalities in health: the effect of maternal education and access to hospital care on cesarean delivery.

Access to health care is an important factor in explaining health inequalities. This study focuses on the issue of access to health care as a driving force behind the social discrepancies in cesarean delivery using data from 707 newborn children in the 2006-2011 birth cohorts of the German Socio-Economic Panel Study (SOEP). Data on individual birth outcomes are linked to hospital data using extracts of the quality assessment reports of nearly all German hospitals. Geographic Information Systems (GIS) are used to assess hospital service clusters within a 20-km radius buffer around mother׳s homes. Logistic regression models adjusting for maternal characteristics indicate that the likelihood to deliver by a cesarean section increases for the least educated women when they face constraints with regard to access to hospital care. No differences between the education groups are observed when access to obstetric care is high, thus a high access to hospital care seems to balance out health inequalities that are related to differences in education. The results emphasize the importance of focusing on unequal access to hospital care in explaining differences in birth outcomes.