MADISON, WI—While the association of neighborhood socioeconomic disadvantage with development of dementia and cognitive decline in older adults is not well known, a new study suggested that identifying risk factors for brain atrophy can help direct new approached to prevent the conditions.
A report in JAMA Neurology discussed the research, which tested whether neighborhood-level socioeconomic disadvantage is associated with decreased brain volume in a cognitively unimpaired population enriched for Alzheimer’s disease risk.1
With researchers from the Geriatric Research Education and Clinical Center at the VA’s William S. Middleton Hospital in Madison, the study team conducted the study from Jan. 6, 2010, to Jan. 17, 2019, .at an academic research neuroimaging center. Researchers, used cross-sectional data on 951 participants from two large, ongoing cohort studies of Alzheimer’s disease—Wisconsin Registry for Alzheimer’s Prevention and Wisconsin Alzheimer’s Disease Research Center clinical cohort.
Participants were cognitively unimpaired based on National Institute on Aging-Alzheimer’s Association workgroup diagnostic criteria for mild cognitive impairment and Alzheimer’s disease, confirmed through a consensus diagnosis panel. The cohort was enriched for Alzheimer’s disease risk, however, based on family history of dementia. Statistical analysis was performed from April 3 to Sept. 27, 2019.
The authors calculated for each of the 637 participant, mean age 63.9, the Area Deprivation Index, a geospatially determined index of neighborhood-level disadvantage, and cardiovascular disease risk indices. Relative neighborhood-level disadvantage was then compared to hippocampal and total brain tissue volume, as assessed by magnetic resonance imaging.
Results indicated that the study subjects living in the 20% most disadvantaged neighborhoods was associated with 4.1% lower hippocampal volume (β = -317.44; 95% CI, -543.32 to -91.56; P = .006) and 2.0% lower total brain tissue volume (β = -20 959.67; 95% CI, -37 611.92 to -4307.43; P = .01), after controlling for intracranial volume, individual-level educational attainment, age and sex.
The authors emphasized that propensity score-matched analyses determined that this association was not due to racial/ethnic or demographic characteristics. Cardiovascular risk score, examined in a subsample of 893 participants, mediated this association for total brain tissue but not for hippocampal volume, they added.
“For cognitively unimpaired individuals, living in the most disadvantaged neighborhoods was associated with significantly lower cerebral volumes, after controlling for maximal premorbid (total intracranial) volume,” the researchers wrote. “This finding suggests an association of community socioeconomic context, distinct from individual-level socioeconomic status, with brain volume during aging. Cardiovascular risk mediated this association for total brain tissue volume but not for hippocampal volume, suggesting that neighborhood-level disadvantage may be associated with these 2 outcomes via distinct biological pathways.”
- Hunt JFV, Buckingham W, Kim AJ, et al. Association of Neighborhood-Level Disadvantage With Cerebral and Hippocampal Volume [published online ahead of print, 2020 Jan 6] [published correction appears in JAMA Neurol. 2020 Feb 17;:]. JAMA Neurol. 2020;e194501.