Morphometric brain changes during aging: Results from a Brazilian necropsy sample

Abstract

The present study aimed to establish the morphometric brain changes during aging in a necropsy series from Brazil and determine whether sexual dimorphisms interfere in these changes.MethodsA cross-sectional study was conducted at the São Paulo Autopsy Service in Brazil where, after informed consent, data was gathered from next of kin interview with reference to clinical status prior to death. Brain weight, volume and density measurements were taken and then adjusted for head circumference. Descriptive statistics and tests of hypothesis and correlations were applied, considering a p-value of 0.05.Results414 subjects, mostly men (60.4%), with a mean age of 67.1 years, were included. The mean brain weight of the sample was 1219.2g±140.9and mean volume was 1217mL±152.3. The mean brain density of the sample was 1.0g/mL±0.09. Values differed between males and females in terms of weight and volume. Brain weight decreased during aging by about 45g per decade (r= –0.300; p<0.01) and volume by about 43mL (r= –0.278; p<0.00). Mean density of the sample was 1.0 g/mL in both genders.ConclusionsBrain weight and volume (with or without corrections) decreased during aging, and these reductions were more pronounced in women. Density remained unchanged for both genders. Further studies are needed to investigate factors associated to these reductions.

Factors associated with morphometric brain changes in cognitively normal aging

“…Previous studies have demonstrated the same association. 1 , 4 - 6 , 8 , 12 , 13 , 17 , 38 The weakness of the correlations may lead to the conclusion that other factors, besides age and gender, also contribute to the phenomenon.…”

“…In order to avoid the secular effect, 1 , 9 , 36 , 37 brain weight and volume was adjusted for head circumference, resulting in adjusted brain weight (g/cm) and volume (mL/cm). Brain weight and volume decreases as head circumference decreases, justifying adjustment of these measures.…”

“…Autopsy studies and neuroimaging have shown reductions in brain weight and volume during aging. 1 - 14 However, most studies did not adjust the measurements of brain weight and volume for head circumference, known to be a factor influencing brain weight and volume changes.…”

Efeitos de programas de exercícios físicos com diferentes níveis de complexidade da tarefa motora na função cognitiva, funcionalidade e parâmetros de marcha de idosos

“…O termo morfologia faz referência ao estudo da forma dos seres vivos, assim morfologia encefálica pode ser entendida como estudo da forma encefálica. Em função do processo de envelhecimento o volume encefálico apresenta redução anual de até 0,3% (FERRETTI et al, 2010). Em comparações com jovens de 20 a 40 anos, idosos de 75 a 85 anos apresentam volume encefálico total 6% menor, mas este é ainda mais pronunciado quando observado o lobo frontal que pode chegar a 10% (HAUG & EGGERS, 1991).…”

“…Tais mudanças no idoso são mais evidentes no nível estrutural (ZHAO et al, 2018), podendo ser destacado a diminuição do volume total do encéfalo (FERRETTI et al, 2010), e do volume de estruturas específicas (ex: substância cinza e branca) (SCHIPPLING et al, 2017). Porém, é sabido que a diminuição do volume do lobo frontal também ocorre com o envelhecimento (LINDBERG, 2012), com evidências que esta é até 80% mais acentuada que a diminuição do volume total encefálico (HAUG & EGGERS, 1991).…”