Pathways explaining racial/ethnic and socio-economic disparities in dementia incidence: the UK Biobank study.

BACKGROUND: Pathways explaining racial/ethnic disparities in dementia risk are under-evaluated. METHODS: We examine those disparities and their related pathways among UK Biobank study respondents (50-74 y, N = 323,483; 3.6% non-White minorities) using a series of Cox proportional hazards and generalized structural equations models (GSEM). RESULTS: After ≤15 years, 5,491 all-cause dementia cases were diagnosed. Racial minority status (RACE_ETHN, Non-White vs. White) increased dementia risk by 24% (HR = 1.24, 95% CI: 1.07-1.45, P = 0.005), an association attenuated by socio-economic status (SES), (HR = 1.12, 95% CI: 0.96-1.31). Total race-dementia effect was mediated through both SES and Life's Essential 8 lifestyle sub-score (LE8LIFESTYLE), combining diet, smoking, physical activity, and sleep factors. SES was inversely related to dementia risk (HR = 0.69, 95% CI: 0.67, 0.72, P < 0.001). Pathways explaining excess dementia risk among racial minorities included 'RACE_ETHN(-) → SES(-) → DEMENTIA', 'RACE_ETHN(-) → SES(-) → Poor cognitive performance, COGN(+) → DEMENTIA' and 'RACE_ETHN(-) → SES(+) → LE8LIFESTYLE(-) → DEMENTIA'. CONCLUSIONS: Pending future interventions, lifestyle factors including diet, smoking, physical activity, and sleep are crucial for reducing racial and socio-economic disparities in dementia.

Life's simple 7 and its association with trajectories in depressive symptoms among urban middle-aged adults.

BACKGROUND: The American Heart Association Life's Simple 7 (LS7) is a composite metric assessing cardiovascular health on a scale of 0-14 comprised of nutrition, physical activity, cigarette use, body mass index, blood pressure, cholesterol and glucose. METHODS: Using data from the Healthy Aging in Neighborhoods of Diversity across the Life Span study [n = 1465, Age at visit 1 (v1: 2004-2009): 30-66 y, 41.7 % male, 60.6 % African American], we investigated associations of trajectories in depressive symptoms (2004-2017) with Life's simple 7 scores after ∼8.6 years follow-up (2013-2017). Analyses used group-based zero-inflated Poisson trajectory (GBTM) models and multiple linear or ordinal logistic regression. GBTM analyses generated two classes of depressive symptoms trajectories ("low declining" and "high declining"), based on intercept and slope direction and significance. RESULTS: Overall, "high declining depressive symptoms" vs. the "low declining" group was associated with -0.67 ± 0.10 lower scores on LS7 total score (P < 0.001) in analyses adjusted for age, sex, race and the inverse mills ratio. This effect was markedly attenuated to -0.45 ± 0.10 score-points (P < 0.001) upon adjustment for socio-economic factors and to -0.27 ± 0.10 score-points (P < 0.010) in fully adjusted analyses, with a stronger association detected among women (ß ± SE: -0.45 ± 0.14, P = 0.002). An association between elevated depressive symptoms over time ("high declining" vs "low declining") and LS7 total score was detected among African American adults (ß ± SE: -0.281 ± 0.131, p = 0.031, full model). Moreover, the "high declining" vs. "low declining" depressive symptoms group was associated with a lower score on LS7 physical activity (ß ± SE: -0.494 ± 0.130, P < 0.001). CONCLUSIONS: Poorer cardiovascular health was linked to higher depressive symptoms over time.

Pathways explaining racial/ethnic disparities in incident all-cause dementia among middle-aged US adults.

INTRODUCTION: Racial disparities in dementia incidence exist, but less is known about their presence and drivers among middle-aged adults. METHODS: We used time-to-event analysis among a sample of 4378 respondents (age 40-59 years at baseline) drawn from the third National Health and Nutrition Examination Surveys (NHANES III) with administrative linkage-spanning the years 1988-2014-to evaluate potential mediating pathways through socioeconomic status (SES), lifestyle, and health-related characteristics. RESULTS: Compared with Non-Hispanic White (NHW) adults, Non-White adults had a higher incidence of AD-specific (hazard ratio [HR] = 2.05, 95% confidence interval [CI]: 1.21, 3.49) and all-cause dementia (HR = 2.01, 95% CI: 1.36, 2.98). Diet, smoking, and physical activity were among characteristics on the pathway between race/ethnicity, SES, and dementia, with health-mediating effects of smoking and physical activity on dementia risk. DISCUSSION: We identified several pathways that may generate racial disparities in incident all-cause dementia among middle-aged adults. No direct effect of race was observed. More studies are needed to corroborate our findings in comparable populations.

Allostatic Load and Cognitive Function Among Urban Adults in the Healthy Aging in Neighborhoods of Diversity across the Life Span Study.

BACKGROUND: Cross-sectional studies have linked cognition to allostatic load (AL) which reflects multisystem dysregulation from life course exposure to stressors. OBJECTIVE: To examine baseline and changes in AL and their relationships with 11 cognitive function test scores, while exploring health disparities according to sex and race. METHODS: Longitudinal [Visit 1 (2004-2009) and Visit 2 (2009-2013)] data were analyzed from 2,223 Healthy Aging in Neighborhoods of Diversity across the Life Span participants. We calculated AL total score using cardiovascular, metabolic, and inflammatory risk indicators, and applied group-based trajectory modeling to define AL change. RESULTS: Overall and stratum-specific relationships were evaluated using mixed-effects linear regression models that controlled for socio-demographic, lifestyle, and health characteristics. Baseline AL was significantly associated with higher log-transformed Part A Trail Making Test score [Loge (TRAILS A)] (ß= 0.020, p = 0.004) and increasing AL was associated with higher Benton Visual Retention Test score [BVRT] (ß= 0.35, p = 0.002) at baseline, in models that controlled for age, sex, race, poverty status, education, literacy, smoking, drug use, the 2010 healthy eating index and body mass index. Baseline AL and AL change were not related to change in cognitive function between visits. There were no statistically significant interaction effects by sex or race in fully-adjusted models. CONCLUSION: At baseline, AL was associated with worse attention or executive functioning. Increasing AL was associated with worse non-verbal memory or visuo-constructional abilities at baseline. AL was not related to change in cognitive function over time, and relationships did not vary by sex or race.

Usual Intake of Flavonoids Is Inversely Associated with Metabolic Syndrome in African American and White Males but Not Females in Baltimore City, Maryland, USA.

Despite research that suggests flavonoids protect against metabolic syndrome (MetS) and evidence that intake of these compounds differs by race, knowledge about whether flavonoid-MetS associations vary among racial groups is limited. This study sought to estimate usual total flavonoid intake in African American and White adults and assess its sex- and sex/race-specific associations with MetS and its risk factors. Analysis of cross-sectional data from 1837 adults participating in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study were analyzed. Usual total flavonoid intake was estimated using the NCI Method, and logistic regression measured its linkages with health outcomes. Among males overall and when stratified by race, odds of MetS and its risk factors low high-density lipoprotein cholesterol (HDL-C) and elevated glucose were lower at the 75th percentile of usual total flavonoid intake than at the 25th percentile (OR for MetS = 0.62; 95% CI = 0.53, 0.71). However, low HDL-C and elevated glucose were positively associated with usual flavonoid intake among females. The comparable associations by race within sex imply that the relationships between flavonoid and health outcomes may be evident across an array of intakes.

Association of Serum Antioxidant Vitamins and Carotenoids With Incident Alzheimer Disease and All-Cause Dementia Among US Adults.

BACKGROUND AND OBJECTIVES: Serum antioxidant vitamins and carotenoids may protect against neurodegeneration with age. We examined associations of these nutritional biomarkers with incident all-cause and Alzheimer disease (AD) dementia among US middle-aged and older adults. METHODS: Using data from the third National Health and Nutrition Examination Surveys (1988-1994), linked with Centers for Medicare & Medicaid follow-up data, we tested associations and interactions of serum vitamins A, C, and E and total and individual serum carotenoids and interactions with incident AD and all-cause dementia. Cox proportional hazards regression models were conducted. RESULTS: After ≤26 years follow-up (mean 16-17 years, 7,283 participants aged 45-90 years at baseline), serum lutein+zeaxanthin was associated with reduced risk of all-cause dementia (65+ age group), even in the lifestyle-adjusted model (per SD: hazard ratio [HR] 0.93, 95% CI 0.87-0.99; p = 0.037), but attenuated in comparison with a socioeconomic status (SES)-adjusted model (HR 0.92, 95% CI 0.86-0.93; p = 0.013). An inverse relationship was detected between serum ß-cryptoxanthin (per SD increase) and all-cause dementia (45+ and 65+) for age- and sex-adjusted models (HR 0.86, 95% CI 0.80-0.93; p < 0.001 for 45+; HR 0.86, 95% CI 0.80-0.93; p = 0.001 for 65+), a relationship remaining strong in SES-adjusted models (HR 0.89, 95% CI 0.82-0.96; p = 0.006 for 45+; HR 0.88, 95% CI 0.81-0.96; p = 0.007 for 65+), but attenuated in subsequent models. Antagonistic interactions indicate putative protective effects of 1 carotenoid may be observed at lower levels other carotenoids or antioxidant vitamin. DISCUSSION: Incident all-cause dementia was inversely associated with serum lutein+zeaxanthin and ß-cryptoxanthin levels. Further studies with time-dependent exposures and randomized trials are needed to test neuroprotective effects of supplementing the diet with select carotenoids. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that incident all-cause dementia was inversely associated with serum lutein+zeaxanthin and ß-cryptoxanthin levels.

Association of Antioxidant Vitamins A, C, E and Carotenoids with Cognitive Performance over Time: A Cohort Study of Middle-Aged Adults.

Carotenoids may strengthen the association of antioxidant vitamins A, C, and E with favorable cognitive outcomes over time, though a few prospective studies have examined this hypothesis. We evaluated the longitudinal data from 1251 participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study (Age at visit 1 in 2004-2009 (v1): 30-65 years). Vitamins A, C, and E dietary intakes and total and individual dietary carotenoids were computed using two 24-h recalls at v1. Cognitive tests, covering global mental status and domains of memory/learning, attention, psychomotor speed, visuo-spatial, language/verbal, and executive function were conducted at v1 and/or v2 (2009-2013); mean ± SD follow-up: 4.66 ± 0.93 years. Mixed-effects linear regression models detected an interaction between vitamin E and total (and individual) carotenoids for three of 11 cognitive tests at v1, with only one meeting the statistical significance upon multiple testing correction whereby vitamin E was linked with greater verbal memory performance in the uppermost total carotenoid tertile (γ0a = +0.26 ± 0.08, p = 0.002), a synergism largely driven by carotenoid lycopene. Vitamins A and C showed no consistent interactions with carotenoids. In conclusion, we provide partial evidence for synergism between vitamin E and carotenoids in relation to better baseline cognitive performance, pending further studies with time-dependent exposures and randomized trials directly examining this synergism.

Dietary antioxidant intake and its association with cognitive function in an ethnically diverse sample of US adults.

BACKGROUND: Dietary antioxidants can inhibit reactions accompanying neurodegeneration and thus prevent cognitive impairment. We describe associations of dietary antioxidants with cognitive function in a large biracial population, while testing moderation by sex, race, and age and mediation by depressive symptoms. METHODS: This was a cross-sectional analysis of 1274 adults (541 men and 733 women) aged 30 to 64 years at baseline (mean [standard deviation] = 47.5 [9.3]) in the Healthy Aging in Neighborhoods of Diversity Across the Lifespan Study, Baltimore city, MD. Cognitive performance in the domains of memory, language/verbal, attention, spatial, psychomotor speed, executive function, and global mental status were assessed. The 20-item Center for Epidemiologic Studies Depression Scale was used to measure depressive symptoms. Dietary intake was assessed with two 24-hour recalls, estimating daily consumption of total carotenoids and vitamins A, C, and E per 1000 kcal. RESULTS: Among key findings, 1 standard deviation (∼ 2.02 mg/1000 kcal) higher vitamin E was associated with a higher score on verbal memory, immediate recall (ß = +0.64 [0.19], p = .001), and better language/verbal fluency performance (ß = +0.53 [0.16], p = .001), particularly among the younger age group. Women with higher vitamin E intake (ß = +0.68 [0.21], p = .001) had better performance on a psychomotor speed test. The vitamin E-verbal memory association was partially mediated by depressive symptoms (proportion mediated = 13%-16%). CONCLUSIONS: In sum, future cohort studies and dietary interventions should focus on associations of dietary vitamin E with cognitive decline, specifically for domains of verbal memory, verbal fluency, and psychomotor speed.