Brain volume decline in aging: evidence for a relation between socioeconomic status, preclinical Alzheimer disease, and reserve

Arch Neurol. 2008 Jan;65(1):113-20. doi: 10.1001/archneurol.2007.27.


Objectives: To assess the relation between socioeconomic status (SES) and structural brain change in nondemented older adults and to ascertain the potential role of preclinical Alzheimer disease (AD).

Design: Cross-sectional and longitudinal observation.

Setting: Alzheimer's Disease Research Center, St Louis, Missouri.

Participants: Volunteer sample of 362 nondemented adults aged 18 to 93 years. The main cohort of 100 was evaluated for dementia and SES; a Clinical Dementia Rating (CDR) of 0 (no dementia) and middle, high-middle, or high SES was required for eligibility. All 362 received magnetic resonance imaging; of the main 100, 91 received follow-up clinical assessment, and 33 received follow-up magnetic resonance imaging over at least a 3-year interval. A separate sample of 58 CDR 0 participants (aged 47 to 86 years) took part in amyloid imaging with Pittsburgh Compound B (PiB) labeled with radioactive carbon ((11)C).

Main outcome measures: Whole-brain volume adjusted for head size (aWBV) and change per year.

Results: aWBV declined by 0.22% per year between the ages of 20 and 80 years with accelerated decline in advanced aging. Controlling for effects of age and sex in older adults (>65 years) with CDR 0, higher SES was associated with smaller aWBV (3.8% difference spanning the sample range from middle to high privilege, P< .01) and more rapid volume loss (0.39% per year to 0.68% per year from middle to high privilege, P< .05). aWBV was reduced by 2.5% in individuals positive for PiB binding (n=9) as compared with individuals negative for PiB binding (n=49, P< .05), supporting an influence of undetected preclinical AD. Follow-up clinical data revealed that brain volume reduction associated with SES was greater in those who later developed very mild dementia (preclinical CDR 0 group, n=19) compared with those who remained nondemented (stable CDR 0 group, n=64; group x SES interaction, P< .05).

Conclusions: Privileged nondemented older adults harbor more preclinical brain atrophy, consistent with their having greater reserve against the expression of AD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Aging / pathology*
  • Aging / psychology
  • Alzheimer Disease / diagnostic imaging
  • Alzheimer Disease / pathology*
  • Alzheimer Disease / psychology
  • Brain / anatomy & histology*
  • Brain / growth & development*
  • Brain / pathology
  • Cognition / physiology
  • Cohort Studies
  • Cross-Sectional Studies
  • Dementia / pathology
  • Dementia / psychology
  • Female
  • Head / anatomy & histology
  • Humans
  • Longitudinal Studies
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Neuropsychological Tests
  • Plaque, Amyloid / diagnostic imaging
  • Plaque, Amyloid / pathology
  • Positron-Emission Tomography
  • Social Class