Association of Lower Hemoglobin Level and Neuropathology in Community-Dwelling Older Persons

Issue title: Physiopathology of Vascular Risk Factors in Alzheimer's Disease

Guest editors: Jack de la Torre

Article type: Review Article

Authors: Shah, Raj C.^{a; b; *} | Schneider, Julie A.^{b; c; d} | Leurgans, Sue^{b; d} | Bennett, David A.^{b; d}

Affiliations: [a] Department of Family Medicine, Rush University Medical Center, Chicago, IL, USA | [b] Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA | [c] Department of Pathology, Rush University Medical Center, Chicago, IL, USA | [d] Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA

Correspondence: [*] Correspondence to: Raj C. Shah, Rush Alzheimer's Disease Center, 600 South Paulina, Suite 1038, Chicago, IL 60612, USA. Tel.: +1 312 563 2902; Fax: +1 312 942 4154; E-mail: Raj_C_Shah@rush.edu.

Abstract: Lower hemoglobin levels have been associated with cognitive decline in older persons. The objective of this study was to investigate the relationship between lower hemoglobin levels and common, age-related neuropathologies associated with cognitive decline. Hemoglobin and neuropathology measures were available in 113 deceased, community-dwelling, older adults participating in the Rush Memory and Aging Project, a prospective, observational, clinical pathology study of aging. The mean hemoglobin level was 13.0 g/dL (SD = 1.4) and was measured 3.2 (SD = 1.3) years prior to death. Thirty-five participants had at least one chronic macroscopic infarction and twenty-nine had at least one chronic microscopic infarction. Eleven participants had Lewy Bodies. The mean Alzheimer's disease pathology score based on a summary measure of neuritic plaques, diffuse plaques, and neurofibrillary tangles was 0.56 unit (SD = 0.56; range = 0, 2.34). Using logistic regression models adjusted for age at death, gender, and education, each g/dL lower hemoglobin level increased the odds for having a chronic macroscopic infarction by 37% (95% CI = 1.01, 1.86) but not for having a chronic microscopic infarction (OR = 1.11; 95% CI = 0.82, 1.52) or Lewy Bodies (OR = 1.07; 95% CI = 0.68, 1.68). In an adjusted multiple regression model, hemoglobin level was not associated with the global AD pathology measure (parameter estimate = −0.02, SE = 0.03, p = 0.6). In secondary analyses, lower hemoglobin levels were associated with higher odds of having a chronic macroscopic infarction in a subcortical region but not with higher total subcortical chronic macroscopic infarction volume. In conclusion, lower hemoglobin levels appear to be associated with chronic macroscopic infarctions but not other common age-related neuropathologies.

Keywords: Diffuse plaque, hemoglobin, macroscopic infarction, Lewy body, microscopic infarction, neuritic plaque, neurofibrillary tangle, neuropathology

DOI: 10.3233/JAD-2012-120952

Journal: Journal of Alzheimer's Disease, vol. 32, no. 3, pp. 579-586, 2012