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The Swedish Twin Registry Past and future use

Published online by Cambridge University Press:  01 August 2014

R. Cederlöf*
Affiliation:
Institute of Hygiene of the Karolinska Institute, Stockholm Dept. of Environmental Hygiene of the National Institute of Public Health, Stockholm
B. Floderus
Affiliation:
Institute of Hygiene of the Karolinska Institute, Stockholm Dept. of Environmental Hygiene of the National Institute of Public Health, Stockholm
L. Friberg
Affiliation:
Institute of Hygiene of the Karolinska Institute, Stockholm Dept. of Environmental Hygiene of the National Institute of Public Health, Stockholm
*
Dept. of Hygiene, Karolinska Institute, Stockholm 60, Sweden

Extract

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The Swedish Twin Registry of the Karolinska Institute comprises about 10 000 sets of twins, and was built up in 1961-1962. It covers about 95% of all Swedish same-sexed twins that were born in the country in 1886-192 5 and were still living as unbroken pairs at the time of compilation.

The compilation procedure has been presented in detail by Cederlöf (1966a), and will be summarized as follows. Since the middle of the last century, a rather unique system for population registration has existed in Sweden. It is based not only on birth records, but also on migration records. As soon as an individual moves away from the place he lives, he has to notify the authorities as to where he moves. This system made it possible for us to follow-up any individual from his place of birth to his next place of living, and so on, until we found his current address or had to discard him as deceased. We started, in that way, with about 41 000 multiple birth records, handscreened from about 3½ million birth records from all Sweden during the period in question, and ended with a series of about 12 000 located sets of twins. Of the remainder, about 26 000 had to be discarded, due to death of one or both partners; 1 000, due to emigration to foreign countries; and 100, due to hospitalization in mental asylums, or home for aged people, etc. In the compilation procedure we lost track of about 1 100 individuals, or 1.5%.

The zygosity of the twins has been determined with the aid of some similarity questions contained in a questionnaire, mailed to all the twins in the registry. Out of several questions, one proved to be of high reliability, namely the very simple question whether the twins as children were as alike as two peas in a pod, or of family likeness only. We assumed that if both twins in a set agreed in saying that they had been as alike as two peas in a pod, the pair was MZ. If they, on the other hand, agreed in saying that they had been of family likeness only, we regarded the pair as DZ. We validated this questionnaire diagnosis by analyzing the outcome from a subsample of 200 pairs who had also been examined serologically in regard to five markers, A1A2BO, MN, Rh, Hp, and Gm. The results were reported here in Rome in 1961 and showed an agreement in diagnoses of 95% for MZ and 90% for DZ (Cederlöf et al, 1061).

Type
Session 19 - Twin Registers and International Cooperation
Copyright
Copyright © The International Society for Twin Studies 1970

References

Cederlöf, R. (1966 a). The twin method in epidemiological studies on chronic disease. Doctoral Dissertation, Stockholm.Google Scholar
Cederlöf, R. (1966Ä). Urban factor and prevalence of respiratory symptoms and “angina pectoris”. Arch. Environ. Health (Chicago), 13: 743748.CrossRefGoogle Scholar
Cederlöf, R., Friberg, L., Jonsson, E., Kaij, L. (1961). Studies on similarity diagnosis in twins with the aid of mailed questionnaires. Acta Genet. (Basel), 11: 338362.Google ScholarPubMed
Cederlöf, R., Friberg, L., Jonsson, E., Kaij, L. (1966 a). Respiratory symptoms and “angina pectoris” in twins with reference to smoking habits. Arch. Environ. Health (Chicago), 13: 726737.CrossRefGoogle ScholarPubMed
Cederlöf, R., Friberg, L., Jonsson, E., Kaij, L., Jonsson, E., Lundman, T. (1966 a). On the validity of mailed questionnaires in diagnosing “angina pectoris” and “bronchitis”. Arch. Environ. Health (Chicago), 13: 738742.CrossRefGoogle ScholarPubMed
Cederlöf, R., Friberg, L., Jonsson, E. (1967 a). Hereditary factors and “angina pectoris”. Arch. Environ. Health (Chicago), 14: 397400.CrossRefGoogle ScholarPubMed
Cederlöf, R., Edfors, M. L., Friberg, L., Jonsson, E. (1967 a). Hereditary factors, “spontaneous cough” and “smoker's cough”. Arch. Environ. Health (Chicago), 14: 401406.CrossRefGoogle ScholarPubMed
Cederlöf, R., Friberg, L. (1969). Mortality in smoking discordant monozygotic and dizygotic twins, 1st Int. Symp. Twin Studies, Rome.Google Scholar
Cederlöf, R., Friberg, L., Hrubec, Z. (1969 a). Cardiovascular and respiratory symptoms in relation to tobacco smoking. A study on American twins. Arch. Environ. Health (Chicago), 18: 934.CrossRefGoogle Scholar
Cederlöf, R., Friberg, L., Hrubec, Z. (1969 b). Background of “angina pectoris”. Relationship between smoking and other social and environmental factors, 1st Int. Symp. Twin Studies, Rome.Google Scholar
Cederlöf, R., Floderus, B., Friberg, L. (1969 c). Cancer in monozygotic and dizygotic twins. Acta Genet. Med. Gemellol., 19: 6974.CrossRefGoogle Scholar
Cederlöf, R., Liljefors, I., Lundman, T. (1969 d). The validity of the questionnaire diagnosis: “angina pectoris”. 1st Int. Symp. Twin Studies, Rome.Google Scholar
College of General Practitioners (1960). British Medical Research Council's Committee on the Aetiology of Chronic Bronchitis: Standardized Questionnaire on Respiratory Symptoms. Brit. Med. J., 2: 1665.Google Scholar
Liljefors, I. (1969). Coronary heart disease in twins. 1st Int. Symp. Twin Studies, Rome.Google Scholar
Lubs, M. L. (1970). Hereditary and environmental influences on allergy. A study on 7000 twin pairs (In press).Google Scholar
Lundman, T. (1966). Smoking in relation to coronary heart disease and lung function in twins. A co-twin control study. Acta Med. Scand., 180: 175.Google Scholar
Rose, G. (1962). The diagnosis of ischaemic heart pain and intermittent claudication in field surveys bulletin. WHO, 27: 645.Google Scholar
Serasi, E., Luft, R. (1967). Insulin response to glucose infusion in diabetic and non-diabetic monozygotic twin pairs. Genetic control of insuline response? Acta Endocr. (København), 55: 330345.Google Scholar