| 1. |
|
|
| 2. |
- Mitchell, KS, et al.
(författare)
-
An investigation of a measure of twins' equal environments
- 2007
-
Ingår i: Twin research and human genetics : the official journal of the International Society for Twin Studies. - : Cambridge University Press (CUP). - 1832-4274. ; 10:6, s. 840-847
-
Tidskriftsartikel (refereegranskat)abstract
- The equal environments assumption, which holds that trait-relevant environments are equally correlated among monozygotic (MZ) and dizygotic (DZ) twin pairs, is essential to twin designs. Violations of this assumption could lead to biased parameter estimates in twin models. A variety of methods and measures have been used to test this assumption. No studies to date have evaluated the measurement invariance of such items or examined the distribution of the underlying equal environments trait. The current study was an investigation of the psychometric properties of a self-report measure of twins' equal environments. Exploratory and confirmatory factor analysis results indicated that items loaded onto ‘child’ and ‘teen’ equal environments factors. Factor loadings and factor variances and their covariance were invariant for MZ and DZ twins; however, DZ twins had significantly lower factor means than MZ twins. Further, these items demonstrated adequate test–retest reliability. Lastly, the child and teen factors may be bimodally distributed, particularly for MZ twin pairs. Measurement invariance issues, as well as distributions of equal environments traits, should be considered when evaluating the equal environments assumption, in order to produce accurate parameter estimates in twin models.
|
|
| 3. |
|
|
| 4. |
- Baker, JH, et al.
(författare)
-
Genetic risk factors for disordered eating in adolescent males and females
- 2009
-
Ingår i: J Abnorm Psychol. - 0021-843X. ; 118:3, s. 576-86
-
Tidskriftsartikel (refereegranskat)abstract
- The etiologic role of genetic and environmental factors on disordered eating was examined in a sample of 15- to 17-year-old female-female, male-male, and opposite-sex twin pairs. Also assessed was whether a single factor is underlying 3 facets (body dissatisfaction, drive for thinness, bulimia) of disordered eating, including the possible importance of sex differences. Univariate model-fitting analyses indicated that genetic factors are more important for girls and environment more important for boys for body dissatisfaction and drive for thinness. A multivariate common factor analysis indicated that a single factor accounted for the association among these 3 facets of disordered eating in both sexes. However, only 50% of the genetic risk for this factor is shared between the sexes.
|
|
| 5. |
|
|
| 6. |
- Baker, JH, et al.
(författare)
-
Intrauterine testosterone exposure and risk for disordered eating
- 2009
-
Ingår i: The British journal of psychiatry : the journal of mental science. - : Royal College of Psychiatrists. - 1472-1465. ; 194:4, s. 375-376
-
Tidskriftsartikel (refereegranskat)abstract
- Previous research has suggested that prenatal testosterone exposure masculinises disordered eating by comparing opposite- and same-gender twins. The objective of the current study is to replicate this finding using a sample of 439 identical and 213 fraternal females, 461 identical and 344 fraternal males, and 361 males and 371 females from opposite-gender twin pairs. Disordered eating was compared across twin types using the Eating Disorder Inventory–2. Inconsistent with previous findings, a main effect of co-twin gender was not found. Our results raise questions about the validity of prior evidence of the impact of prenatal testosterone exposure on patterns of disordered eating.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
