Age-associated cognitive changes in community dwelling adults

National Institute On Aging

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Abstract

We investigated serum 25-hydroxyvitamin D 25(OH)D, dietary and supplemental vitamin D association with cognitive outcomes. Specifically, we examined sex and age-specific and race-specific associations of vitamin D status and intake with longitudinal change in various cognitive domains in a large sample of ethnically and socio-economically diverse US urban adults. Two prospective waves of data from Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study were used. Participants were U.S. adults aged 30-64 years at initial visit, length of follow-up between visits 1 (2004-2009) and 2 (2009-2013) with mean follow-up timeSD were 4.640.93y. Final analytic sample sizes ranged from 1,231-1,803 participants with 1.5-2.0 visits/participant. We assessed cognitive performance using 11 test scores covering domains of global cognition; attention; learning and memory; executive function; visuo-spatial and visuo-construction ability; psychomotor speed; and, language and verbal. Serum 25(OH)D, vitamin D intake and use of supplements containing vitamin D were the key exposures. Based on multiple mixed-effects linear regression models, there was a consistent relationship between vitamin D status (overall) and supplemental intake (older women and African-Americans) with a slower rate of decline in the domain of verbal fluency. Higher dietary intake of vitamin D was linked to slower rate of decline in verbal memory among younger women, and a slower rate of decline in visual memory and visuo-constructive abilities among whites. All other associations were inconsistent. These results suggest that vitamin D status and intakes were inversely related to domain-specific cognitive decline in US urban adults. In a second study, we examined the interactive relations of race and socioeconomic status (SES) to magnetic resonance imaging (MRI)-assessed global brain outcomes with previously demonstrated prognostic significance for stroke, dementia, and mortality. Participants were 147 African Americans (AAs) and whites (ages 33-71 years; 43% AA; 56% female; 26% below poverty) in the Healthy Aging in Neighborhoods of Diversity across the Life Span SCAN substudy. Cranial MRI was conducted using a 3.0 T unit. White matter (WM) lesion volumes and total brain, gray matter, and WM volumes were computed. An SES composite was derived from education and poverty status. We found significant interactions of race and SES for WM lesion volume (b = 1.38; eta = 0.036; p = .028), total brain (b = 86.72; eta = 0.042; p < .001), gray matter (b = 40.16; eta = 0.032; p = .003), and WM (b = 46.56; eta = 0.050; p < .001). AA participants with low SES exhibited significantly greater WM lesion volumes than white participants with low SES. White participants with higher SES had greater brain volumes than all other groups (albeit within normal range). Low SES was associated with greater WM pathology, which is a marker for increased stroke risk in AAs. Higher SES was associated with greater total brain volume-a putative global indicator of brain health and predictor of mortality-in whites. Findings may reflect environmental and interpersonal stressors encountered by AAs and those of lower SES and could relate to disproportionate rates of stroke, dementia, and mortality. We also examined the effects of severe stress on cognitive change. Intimate partner violence (IPV) victimization is associated with a wide range of mental and physical health problems, but little is known about the effect of IPV on cognitive decline. Previous research suggests an association between IPV victimization and cognitive dysfunction, but the few studies that have examined this phenomenon were cross-sectional in design and focused only on female victims of IPV. This study examined cognitive function over time among a diverse population of both male and female victims of IPV. Regression analyses indicated increased completion time on Trail Making Test (TMT) A for both male and female victims of IPV living below poverty as well as for female victims of IPV without previously depressive symptomatology. Results also indicated increased completion time on TMT B for male victims of IPV. Our findings support an association between IPV victimization and increased cognitive decline that is moderated by poverty status and previous depressive symptomatology. In addition to stress, poor diet quality contributes to morbidity, including poor brain health outcomes such as cognitive decline and dementia. African Americans and individuals living in poverty may be at greater risk for cognitive decrements from poor diet quality. Participants were 2090 African Americans and Whites (57 % female, mean age=47.9 years) who completed two 24-hour dietary recalls. We examined cognitive performance and potential interactions of diet quality with race and poverty status using baseline data from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study. Healthy Eating Index-2010 (HEI-2010) scores were calculated and interpreted using federal guidelines. A neurocognitive test battery was administered to evaluate cognitive function over several domains. Using linear regression we found that lower HEI-2010 scores were associated with poorer verbal learning and memory (P<0.05) after adjustment for covariates. Diet quality within the sample was poor. Significant interactions of HEI-2010 and poverty status (all P<0.05) indicated that higher diet quality was associated with higher performance on tests of attention and cognitive flexibility, visuospatial ability and perceptual speed among those below the poverty line. No significant race interactions emerged. Higher diet quality was associated with better performance on two measures of verbal learning and memory, irrespective of race and poverty status. Findings suggest that diet quality and cognitive function are likely related at the population level.