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.