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- Svensson, DA, et al.
(författare)
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Genetic and environmental influences on recurrent headaches in eight to nine-year-old twins
- 1999
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Ingår i: Cephalalgia : an international journal of headache. - : SAGE Publications. - 0333-1024. ; 19:10, s. 866-872
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Tidskriftsartikel (refereegranskat)abstract
- The major objective of the present study was to estimate genetic and environmental influences on recurrent headaches in prepubescent twins. A nationwide cohort of 8 to 9-year-old Swedish twins ( n = 1,480) was screened for nonsymptomatic and recurrent headaches through a questionnaire mailed to their parents (75% response frequency). Among positives, 79% of headaches were classified as migraine or tension-type headache in close accordance with the International Headache Society criteria. The prevalences of migraine and nonmigrainous headaches were 2.4% and 11.3%, respectively, and without significant differences between the sexes or zygosity types. Inheritance on liability to recurrent headaches was estimated to 70% (a2 = 0.70, 95% CI = 0.54 − 0.82) for boys and girls but the genetic effect was found to be uncorrelated between the sexes. We conclude that genetic and individual specific effects are important for recurrent headaches of migrainous and nonmigrainous types in prepubescent children, and that different genetic etiologies might exist for boys and girls.
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| 5. |
- Steffensson, B, et al.
(författare)
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Genetic disposition for global maturity: An explanation for genetic effects on parental report on ADHD
- 1999
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Ingår i: INTERNATIONAL JOURNAL OF BEHAVIORAL DEVELOPMENT. - : SAGE Publications. - 0165-0254 .- 1464-0651. ; 23:2, s. 357-374
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Attention deficit hyperactivity disorder (ADHD) has been shown to be substantially influenced by genetic factors. However it is still not known how these effects are mediated. The aim of this study is to evaluate whether genetic disposition for global maturity could be a mediator of the well-known findings of genetic factors for ADHD symptoms. A total of 1480 pairs of twins aged 8-9 years were identified through the population-based Swedish Twin Registry. A mailed questionnaire with items from DSM-III-R for ADHD and items concerning global maturity were completed by the parents. The results showed that global maturity mediated part of genetic effects for ADHD for both boys and girls. There were also genetic, shared environmental, as well as nonshared environmental effects unique to ADHD not in common with global maturity. Thus, there are at least two pathways through which genetic effects can influence ADHD: one through predisposition for maturational lag and one unique to ADHD, possibly mediated by personality. The results indicate that maturational lag could be of importance for treatment and prognosis of ADHD.
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