gms | German Medical Science

MAINZ//2011: 56. GMDS-Jahrestagung und 6. DGEpi-Jahrestagung

Deutsche Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie e. V.
Deutsche Gesellschaft für Epidemiologie e. V.

26. - 29.09.2011 in Mainz

Sibling study in health insurance data using the example of ADHD in 6-17- year-old children and adolescents

Meeting Abstract

  • Ingo Langner - Bremen Institute for Prevention Research and Social Medicine (BIPS), Bremen
  • Rafael Mikolajczyk - Bremen Institute for Prevention Research and Social Medicine (BIPS), Bremen
  • Tobias Banaschewski - Central Institute of Mental Health, Mannheim
  • Edeltraut Garbe - Bremen Institute for Prevention Research and Social Medicine (BIPS), Bremen

Mainz//2011. 56. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (gmds), 6. Jahrestagung der Deutschen Gesellschaft für Epidemiologie (DGEpi). Mainz, 26.-29.09.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. Doc11gmds133

DOI: 10.3205/11gmds133, URN: urn:nbn:de:0183-11gmds1331

Published: September 20, 2011

© 2011 Langner et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Background: Twin/sibling studies serve as a powerful method for researchers to assess the contribution of genetic factors e.g. in the aetiology of ADHD.

Objectives: To show practicability of twin/sibling studies in children and adolescents based on German health insurance data.

Methods: Data source was the German Pharmacoepidemiological Research Database (GePaRD) which includes about 14 million members of four statutory health insurances representing 17% of the total population of Germany. Based on an identifier which links co-insured members to the belonging main-insured person we identified 327,730 non-twin sibling pairs and 12,486 twin pairs in 2005. Twin pairs were defined as siblings with the same year of birth. Previous investigation based on the date of birth proved the accuracy of this definition in 97.2 % of cases. Each pair was divided into a younger index child (6 to 12 years old) and a co-sibling of the same age or older (6 to 17 years old). We stratified the twin and non-twin pairs into groups by sex of the index child, composition of sex within the pair, and ADHD-status of the co-sibling and analyzed the age adjusted relative risk (RR) of ADHD for the index child in the different strata by using Poisson regression modelling. All analyses were done with SAS version 8.2.

Results: Compared to non-twins of the same sex and no ADHD in the co-sibling (reference) the highest RR for ADHD in the index child was found for twin pairs of the same sex and with ADHD in the co-twin (males RR=12.5, 95%CI 10.0-15.6; females RR=23.9, 95%CI 16.0-35.7). In non-twin female index children the RR of ADHD was higher in the presence of a female co-sibling with ADHD (RR=10.6, 95%CI 8.6-13.0) than in the presence of a male co-sibling with ADHD (RR=6.1, 95%CI 5.1-7.4). In male index children this was the opposite (RR=6.0, 95%CI 5.4-6.8 and RR=8.2, 95%CI 7.1-9.5, respectively).

Conclusions: We demonstrated that twin studies in GePaRD could reproduce findings regarding genetic influences on the aetiology of ADHD [1], [2], [3]. Higher risks for siblings of females with ADHD than for siblings of males with ADHD are in line with the polygenic multiple threshold model favoured by Rhee and Waldman [4].


References

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Burt SA. Rethinking Environmental Contributions to Child and Adolescent Psychopathology: A Meta-Analysis of Shared Environmental Influences. Psychological Bulletin. 2009;135(4):608-–637.
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Wermter A-K, Laucht M, Schimmelmann BG, Banaschweski T, Sonuga-Barke EJS, Rietschel M, Becker K. From nature versus nurture, via nature and nurture, to gene × environment interaction in mental disorders. Eur Child Adolesc Psychiatry. 2010;19:199-–210.
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Rhee SH, Waldman ID. Etiology of Sex Differences in the Prevalence of ADHD: An Examination of Inattention and Hyperactivity–Impulsivity. American Journal of Medical Genetics Part B (Neuropsychiatric Genetics). 2004;127B:60-–64.