Article

Longitudinal and cross-sectional twin data on cognitive abilities in adulthood: the Swedish Adoption/Twin Study of Aging.

Division of Social Sciences, Indiana University Southeast, New Albany 47150, USA.
Developmental Psychology (Impact Factor: 3.21). 12/1998; 34(6):1400-13. DOI: 10.1037//0012-1649.34.6.1400
Source: PubMed

ABSTRACT Cross-sequential methods of analysis, designed to separate age and cohort effects, were applied to data from the Swedish Adoption/Twin Study of Aging. Thirteen cognitive variables were collected at 3 times of measurement separated by 3-year intervals. Data were available from 85 individuals from monozygotic (MZ) pairs reared apart, 132 from MZ pairs reared together, 207 from dizygotic (DZ) pairs reared apart, and 178 from DZ pairs reared together (age range at first assessment: 41-84 years). Time x Cohort interactions were found for mean performance on 8 of the measures, revealing stable mean performance in the younger cohorts and longitudinal decreases in mean performance in the older cohorts. Cohort and time effects for total variance were mixed; little evidence was found for increases in variance with age. Age changes and cohort differences in genetic and environmental components of variance were test-specific; several Cohort x Time interactions attained significance. Heritability of the general cognitive ability factor showed significant longitudinal decreases over time in the older cohorts.

0 Bookmarks
 · 
41 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The relative contributions of genetic and environmental factors to brain structure change throughout the lifespan. Brain structures have been reported to be highly heritable in middle-aged individuals and younger; however, the influence of genes on brain structure is less studied in older adults. We performed a magnetic resonance imaging study of 236 older twins, with a mean age of 71.4 ± 5.7 years, to examine the heritability of 53 brain global and lobar volumetric measures. Total brain volume (63%) and other volumetric measures were moderately to highly heritable in late life, and these genetic influences tended to decrease with age, suggesting a greater influence of environmental factors as age advanced. Genetic influences were higher in men and on the left hemisphere compared with the right. In multivariate models, common genetic factors were observed for global and lobar total and gray matter volumes. This study examined the genetic contribution to 53 brain global and lobar volumetric measures in older twins for the first time, and the influence of age, sex, and laterality on these genetic contributions, which are useful information for a better understanding of the process of brain aging and helping individuals to have a healthy aging.
    Neurobiology of aging 10/2013; DOI:10.1016/j.neurobiolaging.2013.10.079 · 5.94 Impact Factor
  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: Total brain volume (BV) and the volumes of brain substructures are influenced by genes, the magnitude of which changes with age. One approach to the examination of genetic influences on the volumes of brain structures is to determine their heritability using twin and family studies. We reviewed published cross-sectional studies which examined heritability in healthy subjects at different ages. We identified 32 studies, which examined a total of 77 brain volumetric measures. The findings of our review showed that BVs are under significant genetic influence at all ages, although different brain regions showed different heritability levels. Furthermore, the cross-sectional approach of our review found that heritability factor for the majority of BVs declined with age, such as in the total brain and cerebrum, followed by subsequent increment of environmental influences. Overall, this study identified for the first time a cross-sectional pattern for brain structures' heritability changes with age, and suggests the potential for longitudinal investigations in the future.
    Ageing research reviews 11/2013; DOI:10.1016/j.arr.2013.10.003 · 7.63 Impact Factor

Full-text (2 Sources)

Download
112 Downloads
Available from
May 30, 2014