TY - JOUR AU - Magnus, Per AU - Harris, Jennifer R. AU - Tambs, Kristian PY - 2016/07/20 Y2 - 2024/03/29 TI - Setting up and utilizing Norwegian twin panels JF - Norsk Epidemiologi JA - Nor J Epidemiol VL - 26 IS - 1-2 SE - DO - 10.5324/nje.v26i1-2.2011 UR - https://www.ntnu.no/ojs/index.php/norepid/article/view/2011 SP - AB - In the late 1970s, a Norwegian twin panel was set up. It included all like-sexed twin pairs, born in the period<br />1915 to 1960, where both members were alive and had a known address in Norway at the time. The work<br />was initiated through a grant from the National Institutes of Health in the United States. The aim was to estimate<br />maternal effects to understand the causes of variation in traits and diseases that originate in pregnancy.<br />However, the twin panel was also utilized for estimating genetic and environmental effects on a series of<br />phenotypes, for instance lipoproteins, receptors, coagulation factors, cognitive abilities, educational attainment<br />and left-handedness. A short zygosity questionnaire was sent together with the first invitation letter to<br />the twins. Later questionnaires on general health, lifestyles and pregnancy outcomes were sent out. One<br />important finding was that the fetal genotype had much stronger influence on variation in fetal growth than<br />what had been assumed previously. In the early 1990s, the New Norwegian Twin Panel was created, based<br />on information on plural births in the Medical Birth Registry of Norway (MBRN). The panel included both<br />like-sexed and opposite-sexed pairs born in the years 1967 to 1974. After linking the MBRN to present<br />addresses, using a national identification number, a questionnaire on zygosity, with a few items on health<br />and social background, was sent out. This panel was later expanded to include twins born 1975-1979 and to<br />collect more data on health, well-being and lifestyle factors. The data have been utilized for a series of subprojects,<br />including psychiatric interviews and the collection of DNA samples. Linkage to Norwegian health<br />registries has provided important research opportunities for a variety of phenotypic outcomes. ER -