Though diet quality is widely recognised as linked to risk of chronic disease, health systems have been challenged to find a user-friendly, efficient way to obtain information about diet. The Penn Healthy Diet (PHD) survey was designed to fill this void. The purposes of this pilot project were to assess the patient experience with the PHD, to validate the accuracy of the PHD against related items in a diet recall and to explore scoring algorithms with relationship to the Healthy Eating Index (HEI)-2015 computed from the recall data. A convenience sample of participants in the Penn Health BioBank was surveyed with the PHD, the Automated Self-Administered 24-hour recall (ASA24) and experience questions. Kappa scores and Spearman correlations were used to compare related questions in the PHD to the ASA24. Numerical scoring, regression tree and weighted regressions were computed for scoring. Participants assessed the PHD as easy to use and were willing to repeat the survey at least annually. The three scoring algorithms were strongly associated with HEI-2015 scores using National Health and Nutrition Examination Survey 2017–2018 data from which the PHD was developed and moderately associated with the pilot replication data. The PHD is acceptable to participants and at least moderately correlated with the HEI-2015. Further validation in a larger sample will enable the selection of the strongest scoring approach.

The Osaka University Twin Registry was originally established as a registry of older twins but was subsequently expanded to include twins of all ages. The Center for Twin Research at Osaka University Graduate School of Medicine has been managing this registry, as well as collecting research information and bioresources from twin participants. Based on the resources, multidisciplinary research projects have been conducted in collaboration with researchers from institutions both inside and outside Japan. One of the main aims of the center is to collect research information as well as biological resources from registered twins, and to establish a biobank and databases of these data and bioresources. Although data availability may vary, the following data have been collected: physical data (e.g., height, body weight, blood pressure, theoretical visceral fat, pulse wave velocity and bone density); epidemiological data (e.g., medical history, lifestyle, quality of life, mood status, cognitive function and nutritional status); electrocardiography, ultrasonography (carotid artery and thyroid); dentistry, dermatological assessment; positron emission tomography; magnetoencephalographam; brain magnetic resonance imaging (MRI); and functional MRI. In addition to these in-person survey data, microbiome data have been collected from some participants. As for bioresources, peripheral blood is obtained from the participants for isolation of serum and extraction of DNA and RNA, then stored in deep freezers for further analyses. A variety of research projects are in progress and more are on the way both in Japan and internationally using these data.

The Swedish Twin Registry functions as research infrastructure containing information on 216,258 twins born between 1886 and 2015, of whom 86,199 pairs have zygosity determined by DNA, an intrapair similarity algorithm, or being of opposite sex. In essence, practically all twins alive and currently 9 years or older have been invited for participation and donation of DNA on which genomewide single nucleotide polymorphisms array genotyping has been performed. Content, management and alternatives for future improvements are discussed.

The Netherlands Twin Register (NTR) is a national register in which twins, multiples and their parents, siblings, spouses and other family members participate. Here we describe the NTR resources that were created from more than 30 years of data collections; the development and maintenance of the newly developed database systems, and the possibilities these resources create for future research. Since the early 1980s, the NTR has enrolled around 120,000 twins and a roughly equal number of their relatives. The majority of twin families have participated in survey studies, and subsamples took part in biomaterial collection (e.g., DNA) and dedicated projects, for example, for neuropsychological, biomarker and behavioral traits. The recruitment into the NTR is all inclusive without any restrictions on enrollment. These resources — the longitudinal phenotyping, the extended pedigree structures and the multigeneration genotyping — allow for future twin-family research that will contribute to gene discovery, causality modeling, and studies of genetic and cultural inheritance.

The Danish Twin Registry (DTR) was established in the 1950s, when twins born from 1870 to 1910 were ascertained, and has since been extended to include twins from birth cohorts until 2009. The DTR currently comprises of more than 175,000 twins from the 140 birth cohorts. This makes the DTR the oldest nationwide twin register and among the largest in the world. The combination of data from several surveys, including biological samples and repeated measurements on the same individuals, and data from Danish national registers provides a unique resource for a wide range of twin studies. This article provides an updated overview of the data in the DTR: First, we provide a summary of the establishment of the register, the different ascertainment methods and the twins included; then follows an overview of major surveys conducted in the DTR since 1994 and a description of the DTR biobank, including a description of the molecular data created so far; finally, a short description is given of the linkage to Danish national registers at Statistics Denmark and some recent examples of studies using the various data resources in the DTR are highlighted.

The Murcia Twin Registry (MTR) is the only population-based registry in Spain. Created in 2006, the registry has been growing more than a decade to become one of the references for twin research in the Mediterranean region. The MTR database currently comprises 3545 adult participants born between 1940 and 1977. It also holds a recently launched satellite registry of university students (N = 204). Along five waves of data collection, the registry has gathered questionnaire and anthropometric data, as well as biological samples. The MTR keeps its main research focus on health and health-related behaviors from a public health perspective. This includes lifestyle, health promotion, quality of life or environmental conditions. Future short-term development points to the expansion of the biobank and the continuation of the collection of longitudinal data.

The aim of this study was to establish a functional freezing–thawing protocol for epididymal sperm of collared peccaries (Pecari tajacu L., 1758) by comparing different extenders. The epididymal sperm from 12 sexually mature males was recovered by retrograde flushing using Tris-based or coconut water-based (ACP®-116c) extenders. After initial evaluation, samples were diluted and frozen with the same extenders to which 20% egg yolk and 6% glycerol were added. After 2 weeks, thawing was performed at 37°C/60 s and sperm motility, vigour, morphology, functional membrane integrity, sperm viability, sperm plasma membrane integrity, and a computer-assisted semen analysis (CASA) were assessed. In addition, to evaluate the survival of frozen–thawed sperm, a thermal resistance test (TRT) was executed. Samples preserved using Tris were in better condition compared with those preserved using ACP®, showing higher values for most assessments performed, including CASA and the TRT (P<0.05). After determining Tris to be the better of the two extenders, additional samples were thawed using different thawing rates (37°C/60 s, 55°C/7 s, 70°C/8 s). Sperm thawed at 37°C/60 s had the greatest preservation (P<0.05) of viability (54.1 ± 5.9%) and functional membrane integrity (43.2 ± 5.4%), and had higher values for various CASA parameters. In conclusion, we suggest the use of a Tris-based extender added to egg yolk and glycerol for the cryopreservation of epididymal sperm obtained from collared peccaries. In order to achieve better post-thawing sperm quality, we suggest that samples should be thawed at 37°C/60 s.

The Wuhan Pre/Post-Natal Twin Birth Registry (WPTBR) is one of the largest twin birth registries with comprehensive medical information in China. It recruits women from the first trimester of pregnancy and their twins from birth. From January 2006 to May 2016, the total number of twins enrolled in WPTBR is 13,869 twin pairs (27,553 individuals). The WPTBR initiated the Wuhan Twin Birth Cohort (WTBC). The WTBC is a prospective cohort study carried out through incorporation of three samples. The first one comprises 6,920 twin pairs, and the second one, 6,949 twin pairs. Both are population-based samples linked to the WPTBR and include pre- and post-natal information from WPTBR. The second sample includes neonatal blood spots as well. Using a hospital-based approach, we recently developed a third sample with a target enrolment of 1,000 twin pairs and their mothers. These twins are invited, via their parents, to participate in a periodic health examination from the first trimester of pregnancy to 18 years. Biological samples are collected initially from the mother, including blood, urine, cord blood, cord, amniotic fluid, placenta, breast milk and meconium, and vaginal secretions, and later from the twins, including meconium, stool, urine, and blood. This article describes the design, recruitment, follow-up, data collection, and measures, as well as ongoing and planned analyses at the WTBC. The WTBC offers a unique opportunity to follow women from prenatal to postnatal, as well as follow-up of their twins. This cohort study will expand the understanding of genetic and environmental influences on pregnancy and twins’ development in China.

Over the past 25 years, the Adult Netherlands Twin Register (ANTR) has collected a wealth of information on physical and mental health, lifestyle, and personality in adolescents and adults. This article provides an overview of the sources of information available, the main research findings, and an outlook for the future. Between 1991 and 2012, longitudinal surveys were completed by twins, their parents, siblings, spouses, and offspring. Data are available for 33,957 participants, with most individuals having completed two or more surveys. Smaller projects provided in-depth phenotyping, including measurements of the autonomic nervous system, neurocognitive function, and brain imaging. For 46% of the ANTR participants, DNA samples are available and whole genome scans have been obtained in more than 11,000 individuals. These data have resulted in numerous studies on heritability, gene x environment interactions, and causality, as well as gene finding studies. In the future, these studies will continue with collection of additional phenotypes, such as metabolomic and telomere length data, and detailed genetic information provided by DNA and RNA sequencing. Record linkage to national registers will allow the study of morbidity and mortality, thus providing insight into the development of health, lifestyle, and behavior across the lifespan.

The Swedish Twin Registry (STR) today contains more than 194,000 twins and more than 75,000 pairs have zygosity determined by an intra-pair similarity algorithm, DNA, or by being of opposite sex. Of these, approximately 20,000, 25,000, and 30,000 pairs are monozygotic, same-sex dizygotic, and opposite-sex dizygotic pairs, respectively. Since its establishment in the late 1950s, the STR has been an important epidemiological resource for the study of genetic and environmental influences on a multitude of traits, behaviors, and diseases. Following large investments in the collection of biological specimens in the past 10 years we have now established a Swedish twin biobank with DNA from 45,000 twins and blood serum from 15,000 twins, which effectively has also transformed the registry into a powerful resource for molecular studies. We here describe the main projects within which the new collections of both biological samples as well as phenotypic measures have been collected. Coverage by year of birth, zygosity determination, ethnic heterogeneity, and influences of in vitro fertilization are also described.

Over the last 60 years, the resources and the research in the Danish Twin Registry (DTR) have periodically been summarized. Here, we give a short overview of the DTR and a more comprehensive description of new developments in the twenty-first century. First, we outline our experience over the last decade of combining questionnaire and survey data with national demographic, social, and health registers in Statistics Denmark. Second, we describe our most recent data collection effort, which was conducted during the period 2008–2011 and included both in-person assessments of 14,000+ twins born 1931–1969 and sampling of biological material, hereby expanding and consolidating the DTR biobank. Third, two examples of intensively studied twin cohorts are given. The new developments in the DTR in the last decade have facilitated the ongoing research and laid the groundwork for new research directions.