title: Sex differences in cortical thickness in middle aged and early old-aged adults: Personality and Total Health Through Life study.
abstract: BACKGROUND
  The study investigated sex differences in cortical thickness in middle-aged (MA, 44-48 years old, n = 397) and early old-aged (OA, 64-68 years old, n = 398) adults in a community-based sample.
  
  
  METHODS
  T1-weighted three-dimensional structural magnetic resonance imaging scans were acquired in a Fast Field Echo sequence, and cortical thickness was measured with a surface-based segmentation procedure ( http://surfer.nmr.mgh.harvard.edu ).
  
  
  RESULTS
  Results showed that after correcting for age, MA males had predominantly thicker superior temporal cortices, while MA females had thicker occipital, posterior cingulate, precentral, and postcentral cortices. Sex differences in OA adults were less prominent than those in MA adults with females showing thicker temporal and posterior cingulate cortices and males showing thicker rostral middle frontal regions. Between-cohort comparisons revealed that when compared with MA males, OA males showed many regions with significantly thinner cortices, but this pattern was less pronounced for OA females. Our results suggest that sex differences in cortical thickness are age specific, as larger differences in cortical thickness were found in MA compared to OA adults.
  
  
  CONCLUSIONS
  The results of the present study indicate that the inconsistencies in sexual dimorphism that have been reported in the literature are partly due to the variable and transitory nature of cortical thickness differences with age.
authors.affiliation: Centre for Research on Ageing Health and Wellbeing, Australian National University, Building 62a, Canberra, ACT 0200, Australia. prapti.gautam@anu.edu.au
authors.forename: Prapti
authors.initials: P
authors.lastname: Gautam
authors.forename: Nicolas
authors.initials: N
authors.lastname: Cherbuin
authors.forename: Perminder S
authors.initials: PS
authors.lastname: Sachdev
authors.forename: Wei
authors.initials: W
authors.lastname: Wen
authors.forename: Kaarin J
authors.initials: KJ
authors.lastname: Anstey
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000375:Aging / Q000473:pathology*; D001315:Australia / Q000453:epidemiology; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D012737:Sex Factors