Differential Enrollment in Twin Registries: Its Effect on Prevalence and Concordance Rates and Estimates of Genetic Parameters
- 1 April 1985
- journal article
- research article
- Published by Cambridge University Press (CUP) in Acta geneticae medicae et gemellologiae: twin research
- Vol. 34 (3-4), 125-140
- https://doi.org/10.1017/s0001566000004657
Abstract
In the NAS-NRC Registry, all major diseases are more common in DZ than in MZ twins. Furthermore, concordance rates for most disorders are lower in the registry than would be expected. In this article we propose a general model which seeks to explain these phenomena. The model explores the impact of traits which increase or decrease the probability of enrollment of individuals given that the registry, like the NAS-NRC, includes only pairs where both members are enrolled. If the trait decreases the probability of selection into the registry, both the prevalence of and concordance for the trait in the registry will be lower than that found in the population. A trait which increases the probability of selection has the opposite effects. However, the magnitude of these effects are a function of the population concordance. If population concordance differs in MZ and DZ twins, the effect of differential enrollment will not be the same for the two zygosity groups. The article examines the impact of differential enrollment on estimates of heritability and common environment and explores ways in which estimates of prevalence and concordance rates can be obtained which are free of the bias introduced by selection.Keywords
This publication has 10 references indexed in Scilit:
- Schizophrenia in the National Academy of Sciences-National Research Council Twin Registry: a 16-year updateAmerican Journal of Psychiatry, 1983
- Overview: a current perspective on twin studies of schizophreniaAmerican Journal of Psychiatry, 1983
- A Note on Ascertainment Probability in the Allen/Hrubec Twin ModelActa geneticae medicae et gemellologiae: twin research, 1983
- Bias in the estimation of heritability from truncated samples of twinsBehavior Genetics, 1982
- Familial factors in early deaths: Twins followed 30 years to ages 51–61 in 1978Human Genetics, 1981
- Twin Concordance. A More General ModelActa geneticae medicae et gemellologiae: twin research, 1979
- Volunteer bias in twin research: The rule of two‐thirdsSocial Biology, 1978
- EFFECTS OF SELECTION ON MORTALITY1American Journal of Epidemiology, 1974
- The inheritance of liability to certain diseases, estimated from the incidence among relativesAnnals of Human Genetics, 1965
- Studies in Medical SociologyNew England Journal of Medicine, 1944