Graciela Muniz-Terrera1, Annie Robitaille2, Jantje Goerdten1,3, Fernando Massa4, Boo Johansson5. 1. Edinburgh Dementia Prevention & Center for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK. 2. Department of Psychology, University du Quebec a Montreal, Montreal, Canada. 3. Department of Epidemiological Methods and Etiological Research, Leibniz Institute for Prevention Research and Epidemiology-BIPS, Bremen, Germany. 4. Instituto de Estadistica, Universidad de la Republica, Montevideo, Uruguay. 5. Department of Psychology, University of Gothenburg, Gothenburg, Sweden.
Abstract
BACKGROUND: Aging is associated with an increasing risk of decline in cognitive abilities. The decline is, however, not a homogeneous process. There are substantial differences across individuals although previous investigations have identified individuals with distinct cognitive trajectories. Evidence is accumulating that lifestyle contributes significantly to the classification of individuals into various clusters. How and whether genetically related individuals, like twins, change in a more similar manner is yet not fully understood. METHODS: In this study, we fitted growth mixture models to Mini Mental State Exam (MMSE) scores from participants of the Swedish OCTO twin study of oldest-old monozygotic and same-sex dizygotic twins with the purpose of investigating whether twin pairs can be assigned to the same class of cognitive change. RESULTS: We identified four distinct groups (latent classes) whose MMSE trajectories followed different patterns of change over time: two classes of high performing individuals who remained stable and declined slowly, respectively, a group of mildly impaired individuals with a fast decline and a small group of impaired individuals who declined more rapidly. Notably, our analyses show no association between zygosity and class assignment. CONCLUSIONS: Our study provides evidence for a more substantial impact of environmental, rather than genetic, influences on cognitive change trajectories in later life.
BACKGROUND: Aging is associated with an increasing risk of decline in cognitive abilities. The decline is, however, not a homogeneous process. There are substantial differences across individuals although previous investigations have identified individuals with distinct cognitive trajectories. Evidence is accumulating that lifestyle contributes significantly to the classification of individuals into various clusters. How and whether genetically related individuals, like twins, change in a more similar manner is yet not fully understood. METHODS: In this study, we fitted growth mixture models to Mini Mental State Exam (MMSE) scores from participants of the Swedish OCTO twin study of oldest-old monozygotic and same-sex dizygotic twins with the purpose of investigating whether twin pairs can be assigned to the same class of cognitive change. RESULTS: We identified four distinct groups (latent classes) whose MMSE trajectories followed different patterns of change over time: two classes of high performing individuals who remained stable and declined slowly, respectively, a group of mildly impaired individuals with a fast decline and a small group of impaired individuals who declined more rapidly. Notably, our analyses show no association between zygosity and class assignment. CONCLUSIONS: Our study provides evidence for a more substantial impact of environmental, rather than genetic, influences on cognitive change trajectories in later life.
Authors: Kathleen M Hayden; Bruce R Reed; Jennifer J Manly; Douglas Tommet; Robert H Pietrzak; Gordon J Chelune; Frances M Yang; Andrew J Revell; David A Bennett; Richard N Jones Journal: Age Ageing Date: 2011-09-02 Impact factor: 10.668
Authors: Chris J Packard; Rudi G J Westendorp; David J Stott; Muriel J Caslake; Heather M Murray; James Shepherd; Gerard J Blauw; Michael B Murphy; Edward L E M Bollen; Brendan M Buckley; Stuart M Cobbe; Ian Ford; Allan Gaw; Michael Hyland; J Wouter Jukema; Adriaan M Kamper; Peter W Macfarlane; Jellemer Jolles; Ivan J Perry; Brian J Sweeney; Cillian Twomey Journal: J Am Geriatr Soc Date: 2007-11 Impact factor: 5.562
Authors: Gregory J Christie; Tara Hamilton; Bradley D Manor; Norman A S Farb; Faranak Farzan; Andrew Sixsmith; Jean-Jacques Temprado; Sylvain Moreno Journal: Front Aging Neurosci Date: 2017-11-20 Impact factor: 5.750