Norwegian Twin Registers and Norwegian Twin Studies — An Overview

Genetic Factors in Seizures: A Population-Based Study of 47,626 US, Norwegian and Danish Twin Pairs

The purpose of the study was to describe a large sample of twins reporting a history of seizures, to characterize seizures in the three subpopulations, and to estimate the relative importance of genetic and environmental factors in seizure occurrence. Seizure history was determined by questionnaires completed by twins in population-based twin registries in the United States, Norway and Denmark. Concordance rates were calculated for all seizure categories within and across twin populations. Of 47,626 twin pairs evaluated, 6234 reported a history of seizures in one or both twins. Concordance rates were significantly higher for monozygotic (MZ) versus dizygotic (DZ) pairs for all seizure categories within and across populations. The results of this study involving the largest unselected, population-based sample of twins with seizures assembled to date confirm the importance of genetic factors in determining risk for epilepsy, febrile seizures, other seizures and staring spells. This sample is likely to provide an important resource for studying the genetics of epilepsy subtypes and febrile seizures.

The Norwegian Institute of Public Health Twin Program of Research: An Update

The population-based twin program of research at the Norwegian Institute of Public Health (NIPH) was begun in 1992. It consists of a number of questionnaire and clinical interview projects exploring a broad array of mental and physical health outcomes. This article provides a brief update summarizing our research activities, some research highlights, new developments and potentials for further developing the program of twin research. In the most recent years a large effort has concentrated on completing a mental health interview study of Axis I psychiatric and substance use disorders and Axis II personality disorders. Although still in the early planning phases, one of the most significant developments is that an agreement is now in place to centralize the Norwegian twin data into a national Norwegian Twin Registry. This new registry will include twin cohorts born from 1905 onwards. Other resources for building twin projects are described. Nationally, there is great potential for linking the NIPH twin data with other health registries and with information in a number of Norway's large population-based biobank studies. Internationally, platforms such as those developed within GenomEUtwin, for data standards and data sharing and access are greatly facilitating international collaborations in twin research.

The Construction and Prospects of the Chongqing Twin Children Database

Twins could play a crucial role in our understanding of genetic contributions to numerous etiologically complex disorders. In China, although adult twins are relatively rare, twins will become increasingly available due to increasing twin birth rates. Thus, child twin data will be a valuable resource to contribute to the field of child and adolescent psychopathology. The first twin database of children aged from 6 to 16 was established in Chongqing, R.P., China. In this article, we will discuss our experiences in establishing the twin database, completed in three steps — the first step being to search and identify twins, the second being to keep contact with the twins and the final being to seek cooperation with the twin families, and its future prospects. Our twin database has proven to be an efficient method for the investigation and data collection of twin children in China. The results of our present study suggest that the inclusion of twin information in the residence registration of the public security bureaus in the future may ensure a smooth run of research based on the demographic resources. We propose that school networks may be adopted as the preferred method of collection of twin records for future studies.

Development of a national cruciate ligament surgery registry: the Norwegian National Knee Ligament Registry

BACKGROUND

No prospective surveillance system exists for monitoring the outcome of cruciate ligament surgery.

PURPOSE

This article is intended to describe the development and procedures of the Norwegian National Knee Ligament Registry (NKLR), including baseline results from the first 2 years of operation.

STUDY DESIGN

Cohort study (prevalence); Level of evidence, 1.

METHODS

The NKLR was established on June 7, 2004 to collect information prospectively on all cases of cruciate ligament reconstruction surgery in Norway. Information on the details of surgery is gathered through a registration form completed by the surgeon postoperatively, and a validated knee outcome score form is completed by the patients preoperatively and at follow-ups on all patients at 2, 5, and 10 years postoperatively. Hospital compliance was examined in 2005 and 2006.

RESULTS

A total of 2793 primary cruciate ligament reconstruction surgeries were registered by 57 hospitals. This corresponds to an annual population incidence of primary anterior cruciate ligament reconstruction surgeries of 34 per 100,000 citizens (85 per 100 000 citizens in the main at-risk age group of 16-39 years). After 21 months of operation, the NKLR had an overall compliance of 97% when compared with the hospital records.

CONCLUSIONS

A national population-based cruciate ligament registry has been developed, implemented, and maintained in Norway. The registry will each year enroll approximately 1500 primary cruciate ligament reconstruction cases. It is expected that inadequate procedures and devices can be identified, as well as prognostic factors associated with good and poor outcomes, at least for the most frequent categories.