Black-white disparities in functional decline in older persons: the role of cognitive function.
ABSTRACT Black elders have a greater frequency of functional decline than do white elders. The impact of cognitive function on explaining black-white disparities in functional decline has not been extensively explored.
To compare the extent to which different risk domains (comorbidity, smoking, socioeconomic status (SES), self-rated health, and cognitive function) explain more frequent functional decline in black elders, we studied 779 black and 4892 white community-dwelling adults aged 70 and older from the Assets and Health Dynamics Among the Oldest Old (AHEAD), a population-based cohort study begun in 1993. Our primary outcome was worse functional status at 2 years than at baseline. We used logistic regression to compare the unadjusted with the adjusted black-white odds ratios (ORs) after adjusting for each risk domain.
At baseline black participants aged 70-79 had higher rates of smoking, diabetes, and hypertension; lower SES; and worse cognitive function than did white participants (p <.05 for all). The mean cognitive score was 15.7 in black and 21.8 in white participants (p <.01). Black participants had a higher frequency of 2-year functional decline than did white participants (10.9% vs 4.7%; OR = 2.61, 95% confidence interval [CI], 1.69-4.03 adjusted for age and sex). Adjustment for comorbidity and smoking did not significantly change the black-white OR, whereas self-rated health and SES accounted for about half the risk. Adjustment for cognitive function accounted for nearly all the associated decline (OR = 1.10, 95% CI, 0.67-1.79). Among participants aged 80 and over, those who were black had significantly lower risk for functional decline after adjustment for cognitive function (OR = 0.61, 95% CI, 0.38-0.96 vs OR = 1.08, 95% CI, 0.70-1.66 adjusted for age and sex only).
Cognitive function mediated the higher frequency of functional decline among black elders. Efforts to understand cognitive function may enhance our understanding of black-white disparities in health outcomes.
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ABSTRACT: Diabetes mellitus is associated with an increased risk for cognitive impairment and vascular factors seem to play a role in this relationship. In a sample involving elderly African Americans, we tested the hypothesis that diabetes accelerates cognitive decline and explored possible mediating mechanisms within a follow-up period of 15 years. A total of 1,702 subjects, of whom 441 had diabetes, were given the community screening interview for dementia to measure cognitive functioning at six different time points spread over a 15-year follow-up period. Mixed effects models with repeated measures were used to examine the association of diabetes and vascular risk factors with cognitive scores over time. African American subjects with diabetes reported having a significant accelerated cognitive decline as compared with those without diabetes (P = .046), when controlling for basic demographics and baseline comorbid conditions (heart disease, hypertension, stroke, and depression). Adjusting for incident heart disease, and especially stroke, weakened this association (P = .098), thereby indicating a mediating effect of stroke on the association between diabetes and cognitive decline. However, when incident stroke was incorporated into the model, the effect for participants with diabetes increased greatly (P = .007). Diabetes, mediated by cerebrovascular pathology, accelerates cognitive decline within a follow-up period of 15 years in a sample comprising African Americans.Alzheimer's & dementia: the journal of the Alzheimer's Association 07/2011; 7(4):418-24. · 14.48 Impact Factor
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ABSTRACT: This study investigated financial abilities of 154 patients with mild cognitive impairment (MCI) (116 white, 38 African American) using the Financial Capacity Instrument (FCI). In a series of linear regression models, we examined the effect of race on FCI performance and identified preliminary predictor variables that mediated observed racial differences on the FCI. Prior/premorbid abilities were identified. Predictor variables examined in the models included race and other demographic factors (age, education, sex), performance on global cognitive measures (MMSE, DRS-2 Total Score), history of cardiovascular disease (hypertension, diabetes, hypercholesterolemia), and a measure of educational achievement (WRAT-3 Arithmetic). African American patients with MCI performed below white patients with MCI on 6 of the 7 FCI domains examined and on the FCI total score. WRAT-3 Arithmetic emerged as a partial mediator of group differences on the FCI, accounting for 54% of variance. In contrast, performance on global cognitive measures and history of cardiovascular disease only accounted for 14% and 2%, respectively, of the variance. Racial disparities in financial capacity seem to exist among patients with amnestic MCI. Basic academic math skills related to educational opportunity and quality of education account for a substantial proportion of the group difference in financial performance.Alzheimer disease and associated disorders 07/2010; · 2.88 Impact Factor
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ABSTRACT: An older adult's ability to perform physical tasks is predictive of disability onset and is associated with declines in cognition. Risk factors for physical performance declines among African Americans, a group with the highest rates of disability, remain understudied. This study sought to identify demographic, health, and cognitive factors associated with lower-extremity physical performance in a sample of 106 African American women ages 56 to 91. After controlling for global cognitive functioning (Mini Mental State Exam), physical performance was associated with executive functioning (Stroop Color/Word), but not visuospatial construction (WASI Block Design) or processing speed (Trail Making Test, Part A). Executive functioning remained associated with physical performance after entry of demographic variables, exercise, depression, disease burden, and body mass index (BMI). Age, and BMI were also significant in this model. Executive functioning, age and BMI are associated with lower-extremity physical performance among older African American women.Journal of aging research 01/2011; 2011:578609.