@article{Magnusson_Hagen_2016, title={Hereditary and environmental factors causing total joint replacement due to hip and knee osteoarthritis – a twin registry based prospective cohort study}, volume={26}, url={https://www.ntnu.no/ojs/index.php/norepid/article/view/2022}, DOI={10.5324/nje.v26i1-2.2022}, abstractNote={The relative contribution of genetic factors and more modifiable environmental factors to a clinically<br />relevant osteoarthritis (OA) diagnosis is unkown. In this paper we present an ongoing study on the genetic<br />contribution to total joint replacement (TJR) due to hip and knee OA and effects of lifestyle and lifestyle<br />related conditions on TJR due to OA. We have linked data on incident OA from the Norwegian Arthroplasty<br />Registry were l with the Norwegian Twin Registry on the National ID number in 2014, thus obtaining a<br />population based cohort of same-sex twins born 1915-60. Data on height, weight and lifestyle were selfreporteded<br />in questionnaires conducted between 1978 and 1992. The monozygotic (MZ) and dizygotic<br />(DZ) concordances as well as the genetic contribution vs. contribution of more modifiable, environmental<br />factors to arthroplasty will be examined in separate analyses for the hip and the knee joint. The sample<br />comprised N=18058 twins (N=3803 MZ and N=5226 DZ pairs) including N=9650 (53.4%) females and a<br />mean (SD) age of 38 (12.3) years at questionnaire response. Some preliminary analyses have been performed<br />showing a higher concordance for TJR due to hip OA among MZ (0.36) than DZ twins (0.16), which may<br />be consistent with a genetic contribution to hip OA. TJR due to hip OA may be determined by genetic<br />factors. Results for the knee joint as well as final results from hereditary analyses and co-twin control<br />analyses of will be published consecutively from 2016.}, number={1-2}, journal={Norsk Epidemiologi}, author={Magnusson, Karin and Hagen, Kåre Birger}, year={2016}, month={Jul.} }