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- Alexanderson, Camilla, 1978, et al.
(författare)
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Influence of having a male twin on body mass index and risk for dyslipidemia in middle-aged and old women.
- 2011
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Ingår i: International Journal of Obesity. - : Springer Science and Business Media LLC. - 0307-0565 .- 1476-5497. ; 35
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Tidskriftsartikel (refereegranskat)abstract
- Background:Animal experiments suggest that exposure to elevated levels of androgens during development by means of so-called hormonal programming causes metabolic aberrations at adulthood. An indirect strategy to address the possible importance of such an influence also in humans would be to study female dizygotic twins, presuming that those with a twin brother-due to diffusion of testosterone-have been exposed to higher androgen levels prenatally.Design:We have compared 8409 women with a male twin with 9166 women with a dizygotic female twin with respect to self-reported indices of anthropometry and metabolic aberrations at age 42 or older.Results:Body mass index (BMI), body weight and rate of dyslipidemia were moderately, but significantly, higher in women from opposite-sexed (OS) twin pairs; splitting for age revealed this difference to be present in those 60 years of age only.Conclusion:The results (i) support the notion that comparisons of women with a twin brother with women from same-sexed twin pairs may be used to shed light on possible long-term effects of interindividual variations in early androgen exposure, and (ii) suggest that the effects of early androgen exposure on metabolism previously observed in animal experiments are of relevance also for humans.International Journal of Obesity advance online publication, 8 March 2011; doi:10.1038/ijo.2011.18.
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| 2. |
- Baker, J. H., et al.
(författare)
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Sex differences and developmental stability in genetic and environmental influences on psychoactive substance consumption from early adolescence to young adulthood
- 2011
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Ingår i: Psychological Medicine. - New York, USA : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 41:9, s. 1907-1916
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Tidskriftsartikel (refereegranskat)abstract
- Background: Genetic and environmental factors are important in the etiology of substance use. However, little is known about the stability of these factors across development. We aimed to answer three crucial questions about this etiology that have never been addressed in a single study: (1) Is there a general vulnerability to substance consumption from early adolescence to young adulthood? (2) If so, do the genetic and environmental influences on this vulnerability change across development? (3) Do these developmental processes differ in males and females?Method: Subjects included 1480 twin pairs from the Swedish Twin Study of Child and Adolescent Development who have been followed since 1994. Prospective, self-reported regular smoking, alcohol intoxication and illicit drug use were assessed at ages 13-14, 16-17 and 19-20 years. Structural modeling was performed with the program Mx.Results: An underlying common factor accounted for the association between smoking, alcohol and illicit drug consumption for the three age groups. Common genetic and shared environmental effects showed substantial continuity. In general, as participants aged, the influence of the shared environment decreased, and genetic effects became more substance specific in their effect.Conclusions: The current report answers three important questions in the etiology of substance use. The genetic and environmental risk for substance consumption is partly mediated through a common factor and is partly substance specific. Developmentally, evidence was strongest for stability of common genetic effects, with less evidence for genetic innovation. These processes seem to be the same in males and females.
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