Sigurdur Sigurdsson1, Thor Aspelund1,2, Lars Forsberg3, Jesper Fredriksson3, Olafur Kjartansson, 1,4, Palmi V. Jonsson, 1,4, Gudny Eiriksdottir1, Tamara B. Harris5, Alex Zijdenbos6, Mark A. van Buchem7, Lenore J. Launer5, Vilmundur Gudnason1,2
1The Icelandic Heart Association, Kopavogur, Iceland; 2The University of Iceland, Reykjavik, Iceland; 3Raforninn Inc, Reykjavik, Iceland; 4The University Hospital of Iceland, Reykjavik, Iceland; 5The National Institute on Aging, Bethesda, United States; 6Biospective Inc, Montreal, Canada; 7Leiden University Medical Center, Leiden, Netherlands
Estimations on age-related rate of changes of brain tissues have mostly been gathered from cross-sectional MRI studies. A limitation of cross-sectional design is the inability to directly assess intra-individual change. Longitudinal studies on brain tissues and age in large population cohorts are lacking. We compared estimated rates of cross-sectional and longitudinal changes with age in brain tissues in a population-based cohort of 4614 older persons. The longitudinal data show a substantially higher age-related rate of change in tissue volumes when compared to the cross-sectional estimates and show that the cross-sectional data underestimates the rate of change in brain tissues.