Association of Plasma Biomarkers of Alzheimer Disease With Cognition and Medical Comorbidities in a Biracial Cohort

BACKGROUND AND OBJECTIVES

Recent advances in blood-based biomarkers offer the potential to revolutionize the diagnosis and management of Alzheimer disease (AD), but additional research in diverse populations is critical. We assessed the profiles of blood-based AD biomarkers and their relationships to cognition and common medical comorbidities in a biracial cohort.

METHODS

Participants were evaluated through the Mayo Clinic Jacksonville Alzheimer Disease Research Center and matched on age, sex, and cognitive status. Plasma AD biomarkers (β-amyloid peptide 1-42 [Aβ42/40], plasma tau phosphorylated at position 181 [p-tau181], glial fibrillary acidic protein [GFAP], and neurofilament light) were measured using the Quanterix SiMoA HD-X analyzer. Cognition was assessed with the Mini-Mental State Examination. Wilcoxon rank sum tests were used to assess for differences in plasma biomarker levels by sex. Linear models tested for associations of self-reported race, chronic kidney disease (CKD), and vascular risk factors with plasma AD biomarker levels. Additional models assessed for interactions between race and plasma biomarkers in predicting cognition.

RESULTS

The sample comprised African American (AA; N = 267) and non-Hispanic White (NHW; N = 268) participants, including 69% female participants and age range 43-100 (median 80.2) years. Education was higher in NHW participants (median 16 vs 12 years, p < 0.001) while APOE ε4 positivity was higher in AA participants (43% vs 34%; p = 0.04). We observed no differences in plasma AD biomarker levels between AA and NHW participants. These results were unchanged after stratifying by cognitive status (unimpaired vs impaired). Although the p-tau181-cognition association seemed stronger in NHW participants while the Aβ42/40-cognition association seemed stronger in AA participants, these findings did not survive after excluding individuals with CKD. Female participants displayed higher GFAP (177.5 pg/mL vs 157.73 pg/mL; p = 0.002) and lower p-tau181 (2.62 pg/mL vs 3.28 pg/mL; p = 0.001) levels than male participants. Diabetes was inversely associated with GFAP levels (β = -0.01; p < 0.001).

DISCUSSION

In a biracial community-based sample of adults, we observed that sex differences, CKD, and vascular risk factors, but not self-reported race, contributed to variation in plasma AD biomarkers. Although some prior studies have reported primary effects of race/ethnicity, our results reinforce the need to account for broad-based medical and social determinants of health (including sex, systemic comorbidities, and other factors) in effectively and equitably deploying plasma AD biomarkers in the general population.

Creating a Dementia Friendly Community in an African American Neighborhood: Perspectives of People Living with Dementia, Care Partners, Stakeholders, and Community Residents

A dementia friendly community allows people with dementia and their care partners to remain engaged in their community well into the disease. This study presents the results of primary research aimed at exploring perceptions regarding building a dementia friendly community in an African American neighborhood in northeast Florida. Twelve focus groups and five interviews were conducted with people living with dementia, informal and formal care partners, community stakeholders and neighborhood residents, and analyzed using a grounded theory approach. Three main themes emerged from the analyses, including (1) perceived needs, (2) facilitators and barriers to being dementia friendly, and (3) opportunities for the community to become more dementia friendly. Study findings highlight the unique needs of a single African American neighborhood and the importance of culturally tailoring the dementia friendly model to diverse communities.

Nutrition and Emotional Health Education: The Use of Emotional Intelligence and a Plant-Based Diet to Reduce Cardiometabolic Risk

Background

For individuals living with chronic conditions like diabetes mellitus and obesity, there is a need for sustainable behavioral strategies and physiologic tools. These tools support identifying and addressing barriers to healthy eating, reducing body mass index (BMI), and building increased physical resilience in real time.

Objective

To evaluate whether a 12-week learning management system designed to combine nutritional intervention with education and coaching on improving emotional intelligence (EI) could alter cardiometabolic outcomes.

Methods

This pre-post prospective study enrolled 37 adult volunteers with BMI greater than 25 to participate in a 12-week learning management system. Primary (BMI, systolic blood pressure, diastolic blood pressure, low-density lipoprotein [LDL], high-density lipoprotein, and fasting glucose levels) and secondary self-reported outcomes were assessed at baseline, 12 weeks, and 6 months after enrollment using Short Form-36, Emotional Quotient Inventory (EQi), and Whole Health Index (WHI). Linear mixed-effects regression models with random effect were used to estimate changes in primary and secondary outcomes. We adjusted for multiple testing using Holm step-down method.

Results

BMI and LDL were the only primary endpoints lower at program completion and 6-month follow-up compared to baseline levels (-1.63 and -17.77 mg/dL, respectively; P < .001). Secondary outcomes showing statistically significant improvement from baseline to 6-month follow-up included energy/fatigue (Short Form-36), self-regard (EQi), decision-making (EQi), impulse control (EQi), stress management (EQi), Whole Brain - Form A (WHI), Whole Food - Form C (WHI), and Whole Body - Form D (WHI).

Conclusion

This study provides preliminary evidence that lifestyle programs combining nutritional interventions and EI can have a significant impact on BMI and LDL. Our study highlights the potential importance of both nutrition and EI in programs targeting diet and lifestyle modification.

Testing an Alzheimer's Disease Educational Approach in Two African American Neighborhoods in Florida

African Americans experience a significantly greater burden of Alzheimer's disease (AD) compared to non-Hispanic White Americans. Raising awareness and increasing knowledge of AD within African American communities is an important step towards addressing these disparities. The purpose of this study was to assess the effectiveness of two approaches to sharing AD knowledge with community residents. Using a quasi-experimental design, African American participants were recruited through community partners and local resources in two comparable neighborhoods in Duval County, Florida, which formed the intervention and the comparison groups for this study. The identical 40-min educational lecture was provided to both groups. In the intervention community, the lecture was followed by focus group sessions modeled after the Dementia Friendly America toolkit. In the comparison community, the lecture was followed by a social event where participants could interact informally with the speaker and dementia outreach staff. A brief quantitative survey assessing AD knowledge was administered to participants in both groups before the education session, immediately after the lecture, and 2 months later. Results indicate that both groups improved their knowledge scores at immediate post-test. Scores for both groups declined at 2-month follow-up, but the comparison group's scores declined more precipitously than the intervention group's scores (p = 0.0.21). These results suggest that conducting focus groups and interviews following a lecture on AD may help better retain AD knowledge over time.

Cutaneous larva migrans in the city

Cutaneous larva migrans is typically reported in tropical and subtropical regions of the world. However, cutaneous larva migrans cases are spreading and should now be recognized even in urban, nontropical settings.

Patient-Centered Medical Home With Colocation: Observations and Insights From an Academic Family Medicine Clinic

There is a movement in the United States to transform family medicine practices from single physician–based patient care to team-based care. These teams are usually composed of multiple disciplines, including social workers, pharmacists, registered nurses, physician assistants, nurse practitioners, and physicians. The teams support patients and their families, provide holistic care to patients of all ages, and allow their members to work to the highest level of their training in an integrated fashion. Grouping care team members together within visual and auditory distance of each other is likely to enhance communication and teamwork, resulting in more efficient care for patients. This grouping is termed colocation. The authors describe how the use of colocation can lead to clearer, faster communication between care team members. This practice style has the potential to be expanded into various clinical settings in any given health system and to almost all clinical specialties and practices.

Health Behaviors and Preventive Healthcare Utilization Among African-American Attendees at a Faith-Based Public Health Conference: Healthy Churches 2020

Unhealthy eating habits and physical inactivity along with lack of access to quality healthcare contribute to the marked health disparities in chronic diseases among African-Americans. Faith-based public health conferences offer a potential opportunity to improve health literacy and change health behaviors through health promotion within this population, thereby reducing health disparities. This study examined the self-reported health behaviors and preventive healthcare utilization patterns of 77 participants at a predominantly African-American faith-based public health conference, Healthy Churches 2020. A self-administered questionnaire was distributed to a sample of attendees to assess their health behaviors (diet and physical activity), preventive healthcare utilization (annual healthcare provider visits), and health-promoting activities at their places of worship. The results indicate that attendees of a faith-based public health conference have adequate preventive healthcare utilization, but suboptimal healthy behaviors. Our findings support the need for ongoing health-promoting activities with an emphasis on diet and physical activity among this population.

African American Dementia Caregiver Problem Inventory: Descriptive analysis and initial psychometric evaluation

OBJECTIVES

The primary objectives of the present study were: (a) to develop the African American Dementia Caregiver Problem Inventory (DCPI-A) that assesses the types and frequency of problems reported by African American dementia caregivers seeking cognitive-behavioral intervention, (b) to evaluate the intercoder reliability of the DCPI-A, and (c) to measure the perceived severity of common problems reported by this caregiver population.

METHOD

The development of the DCPI-A was divided into 3 major steps: (a) creating an initial sample pool of caregiver problems derived from 2 parent randomized clinical trials, (b) formulating a preliminary version of the DCPI-A, and (c) finalizing the development of the DCPI-A that includes 20 problem categories with explicit coding rules, definitions, and illustrative examples.

RESULTS

The most commonly reported caregiver problems fell into 5 major categories: (a) communication problems with care recipients, family members, and/or significant others, (b) problems with socialization, recreation, and personal enhancement time; (c) problems with physical health and health maintenance, (d) problems in managing care recipients' activities of daily living; and (e) problems with care recipients' difficult behaviors. Intercoder reliability was moderately high for both percent agreement and Cronbach's kappa. A similar positive pattern of results was obtained for the analysis of coder drift.

CONCLUSIONS

The descriptive analysis of the types and frequency of problems of African American dementia caregivers coupled with the outcomes of the psychometric evaluation bode well for the adoption of the DCPI-A in clinical settings. (PsycINFO Database Record

Diagnostic validity of age and education corrections for the Mini-Mental State Examination in older African Americans

OBJECTIVES

To investigate whether demographic (age and education) adjustments for the Mini-Mental State Examination (MMSE) attenuate mean score discrepancies between African-American and Caucasian adults and whether demographically adjusted MMSE scores improve the diagnostic classification accuracy of dementia in African-American adults over unadjusted MMSE scores.

DESIGN

Cross-sectional study.

SETTING

Community-dwelling adults participating in the Mayo Clinic Alzheimer's Disease Patient Registry and Alzheimer's Disease Research Center.

PARTICIPANTS

Three thousand two hundred fifty-four adults (2,819 Caucasian, 435 African American) aged 60 and older.

MEASUREMENTS

MMSE score at study entry.

RESULTS

African-American adults had significantly lower unadjusted MMSE scores (23.0 ± 7.4) than Caucasian adults (25.3 ± 5.4). This discrepancy persisted despite adjustment of MMSE scores for age and years of education using established regression weights or newly derived weights. Controlling for dementia severity at baseline and adjusting MMSE scores for age and quality of education attenuated this discrepancy. In African-American adults, an age- and education-adjusted MMSE cut score of 23/24 provided optimal dementia classification accuracy, but this represented only a modest improvement over an unadjusted MMSE cut score of 22/23. The posterior probability of dementia in African-American adults is presented for various unadjusted MMSE cut scores and prevalence rates of dementia.

CONCLUSION

Age, dementia severity at study entry, and quality of educational experience are important explanatory factors in understanding the existing discrepancies in MMSE performance between Caucasian and African-American adults. These findings support the use of unadjusted MMSE scores when screening older African Americans for dementia, with an unadjusted MMSE cut score of 22/23 yielding optimal classification accuracy.

A preliminary study comparing attitudes toward hospice referral between African American and white American primary care physicians

End-of-life (EOL) decision making is an integral component of high-quality health care. Factors influencing individual primary care physicians (PCPs) can affect their perspectives and referral preferences for EOL care. Numerous barriers have been cited, including patient and family readiness, physicians' comfort with discussing death, and the pursuit of a cure. This study explores another barrier by examining physician ethnicity and comparing the attitudes toward hospice referral between African American and white American primary care providers (PCPs). Training PCPs to efficiently transition from a curative model of care to a palliative model of care has the potential to increase the level of appropriate EOL care, increase hospice referral, and enhance patient and provider satisfaction; it is also fiscally prudent. This preliminary study aims to compare attitudes toward hospice referral and physicians' personal experiences with hospice between African American and white American PCPs.

METHODS

The survey tool was developed by PCPs at the Mayo Clinic Florida after a full literature review and consultation with hospice physicians, oncology specialists, and primary care colleagues from the residency programs at Mayo Minnesota and Mayo Arizona, with input from the Mayo Survey Office, and distributed to all physicians and residents in the departments of Family Medicine at via Mayo's intranet; Mayo's Midwest Regional Practices (245 physicians) received the survey via standard mail. The survey consisted of 17 questions regarding attitudes toward hospice referral and the one question regarding physicians' personal experience with hospice. The final sample size consisted of 167 white American physicians and 46 African American physicians. Responses were compared using a Wilcoxon rank sum test. P values ≤ 0.05 were considered statistically significant. All statistical analyses were performed using the SAS software package (SAS Institute, Cary, North Carolina).

RESULTS

The distributions of physician age, specialty, board certification, and years practicing medicine were similar between African American and white American physicians, while male gender was more common in white American physicians than African American physicians. Statistically significant differences in attitudes toward hospice between African American and white American physicians were observed for five of the 17 survey questions. There was a dramatic difference in the distribution of patient race between African American and white American physicians, raising the possibility that any differences between white American and African American physicians could be attributed to patient race, rather than physician race. Due to survey limits, larger studies involving more African American physicians are needed to address this topic.

CONCLUSION

The results of our preliminary study suggest that certain attitudes toward hospice referral may differ between African American and white American PCPs. If validated, further insight into this issue could lead to educational programs for PCPs that correct misperceptions.

Internal Consistency and Test-Retest Stability of the Geriatric Depression Scale-Short Form in African American Older Adults

The Geriatric Depression Scale (GDS) is one of the most widely used self-rated mood questionnaires for older adults. It is highly correlated with clinical diagnoses of depression and has demonstrated validity across different patient populations. However, the reliability of the GDS among African American older adults remains to be firmly established. In a baseline sample of 401 African American adults age 51 and over, the GDS-15 item short form demonstrates good internal consistency (KR20=.71). Stability over a 15-month interval in a retest sample of 51 adults is deemed adequate (r=.68). These findings support the use of the GDS-15 item short form as a reliable mood questionnaire among African American older adults.

Disparities in participation in cancer clinical trials in the United States : a symptom of a healthcare system in crisis

Disparities in minorities' representation in cancer clinical trials have been shown only in adult populations, which suggest that the main causes of these disparities relate to health system-based barriers, including issues of poverty (lack of insurance), poor access to trials, and an inadequate number of clinical trials. Initiatives that increase the participation of community physicians in cancer clinical research trials and increase low socioeconomic status patients' access to cancer trials will likely ameliorate this problem.

Reliable change on the Dementia Rating Scale

A central role for neuropsychological evaluations is the measurement of change in cognitive functioning over time. However, change scores obtained from repeated neuropsychological assessments may be affected by normal variability because of measurement error and practice effects caused by repeated measurements. The current study uses reliable change estimates to establish normative rates of change on the Dementia Rating Scale from baseline to first follow-up testing among 1080 cognitively normal adults aged 65 and older. Results showed that a 6-point decline by European Americans or a 9-point decline by African American adults within a 9-15 month test-retest interval represents reliable change. Within a 16-24-month test-retest interval, a 7-point decline among European Americans or an 8-point decline among African American adults represents reliable change. In addition, preliminary cross-validation was performed in a clinical comparison sample of another 22 older adults. The findings are discussed in the context of potential clinical and research applications.

Mayo's Older African American Normative Studies: norms for the Mattis Dementia Rating Scale

Normative data are presented for older African Americans on the Mattis Dementia Rating Scale (DRS). These data were collected as part of Mayo's Older African Americans Normative Studies (MOAANS) in an effort to develop age-appropriate norms for African Americans elders on commonly used measures in neuropsychological assessment. In this study, the DRS was administered to 307 MOAANS participants ranging in age from 56 to 94 years. Age-corrected subtest and total scores were derived based on percentile ranks from actual frequency distributions across seven age ranges. Also presented is a regression-based computational formula that may be applied to the age-corrected DRS total score to further correct for years of education. These norms should help improve interpretation of DRS performance in African Americans and allow for greater diagnostic accuracy in patients with early cognitive decline.

Mayo's Older African American Normative Studies: Auditory Verbal Learning Test norms for African American elders

The Auditory Verbal Learning Test (AVLT) is frequently used in clinical practice to assess for memory dysfunction in the elderly. As part of the Mayo Older African Americans Normative Studies (MOAANS), we provide age and education adjusted normative data for the AVLT. The sample consists of 306 self-identified African Americans who are cognitively normal, community-dwelling and ranging in age from 56 through 94. Additional summary indices are included in the normative data, including learning efficiency, delayed recall, percent retention, and an index representing recognition memory corrected for false-positive identifications. Given the importance of using a normative reference sample that closely represents the population of interest, the current norms should provide clinically useful data for evaluating African American elders, especially those who were educated in the southern United States.

Mayo's Older African Americans Normative Studies: norms for Boston Naming Test, Controlled Oral Word Association, Category Fluency, Animal Naming, Token Test, WRAT-3 Reading, Trail Making Test, Stroop Test, and Judgment of Line Orientation

Normative data for older African Americans are presented for several clinical neuropsychological measures, including Boston Naming Test, Controlled Oral Word Association, Category Fluency, Token Test, WRAT-3 Reading, Trail Making Test, Stroop Color and Word Test, and Judgment of Line Orientation. Age-adjusted norms were derived from a sample of 309 cognitively normal, community-dwelling individuals, aged 56 through 94, participating in Mayo's Older African Americans Normative Studies (MOAANS). Years of education were modelled on age-scaled scores to derive regression Equations that may be applied for further demographic correction. These data should enhance interpretation of individual test performances and facilitate analysis of neuropsychological profile patterns in older African American patients who present for dementia evaluations.

Mayo's Older African Americans Normative Studies: normative data for commonly used clinical neuropsychological measures

This report describes the methodology and sample characteristics of Mayo's Older African Americans Normative Studies (MOAANS). These studies reflect a multidisciplinary, collaborative effort by investigators at Mayo Clinic to provide age-appropriate normative data for African American elders on commonly used neuropsychological tests. A sample of 309 community-dwelling individuals over age 55 contributed to the MOAANS sample. Norms were calculated for midpoint age groups, based on percentile scores derived from cumulative frequencies of raw test scores. Demographic, medical, and sociocultural data were also collected, and are summarized to assist clinicians in making determinations regarding the appropriateness of these norms for individual patients. In most cases, the use of MOAANS norms should improve diagnostic accuracy in dementia evaluations of African American elders.

A Brief Report on WAIS-R Normative Data Collection in Mayo's Older African Americans Normative Studies

Historically, neuropsychological measures such as the Wechsler Adult Intelligence Scale-Revised (WAIS-R) have yielded unacceptably high rates of misdiagnosis of impairment among cognitively normal African Americans, primarily due to poor test specificity and inadequate representation of ethnic minorities in the normative sample. In this report, we briefly review these issues and describe efforts by investigators in Mayo's Older African Americans Normative Studies (MOAANS) to develop more appropriate norms for African American elders on the WAIS-R. During MOAANS data collection, the third edition of the WAIS (WAIS-III) was introduced with updated representation of ethnic minorities in the normative database. More recently, specific demographic corrections for African Americans have been derived for WAIS-III subtest scores and indices. As such, WAIS-R normative estimates are not presented here. Interested readers who wish to obtain a full set of MOAANS WAIS-R norms, however, are invited to contact the authors for these data.

Mayo's Older African Americans Normative Studies: WMS-R Norms for African American Elders

Norms for African American elders on the Wechsler Memory Scale-Revised (WMS-R) were derived from a sample of 309 community-dwelling individuals participating in Mayo's Older African Americans Normative Studies (MOAANS). Normative estimates are provided for traditional WMS-R subtest scores and for supplemental procedures to evaluate forgetting rates and recognition memory. Tables are provided to convert raw WMS-R subtest and supplemental scores to age-corrected scaled scores. These may be further adjusted for years of education, if desired, by applying regression-based corrections. We anticipate that these data will enhance the diagnostic utility and clinical interpretation of WMS-R performance in older African Americans.

Mayo's older African American normative studies: confirmatory factor analysis of a core battery

Covariance structure analyses of a core neuropsychological test battery consisting of the Wechsler Adult Intelligence Scale-Revised, Wechsler Memory Scale-Revised, and Auditory Verbal Learning Test have previously identified a 5-factor model in a sample of cognitively normal White volunteers from Mayo's Older Americans Normative Studies (MOANS). The present study sought to replicate this factor structure in a sample of 289 cognitively normal, community-dwelling African American elders from Mayo's Older African Americans Normative Studies (MOAANS). The original 5-factor model was tested against 2 alternative 4-factor models and a 6-factor model generated on a substantive basis. Confirmatory factor analysis supported the construct validity of this core battery in older African Americans by replicating the original 5-factor model of Verbal Comprehension, Perceptual Organization, Attention/Concentration, Learning, and Retention as viable in the present sample.

Association between apolipoprotein E genotype and Alzheimer disease in African American subjects

BACKGROUND

The association between Alzheimer disease (AD) and genotypes at the apolipoprotein E (APOE) locus has been confirmed in numerous populations worldwide, but appears to be inconsistent in African American subjects.

OBJECTIVE

To investigate the association between APOE genotypes and AD in elderly African American subjects.

DESIGN

Clinic-based, multicenter case-control study and a family study.

PARTICIPANTS

A total of 338 African American probands meeting criteria for probable or definite AD, 301 cognitively healthy, elderly unrelated control subjects (spouses and community volunteers), and 108 siblings of 88 AD probands.

MAIN OUTCOME MEASURES

Odds of AD according to APOE genotype.

RESULTS

Compared with individuals with the APOEepsilon3/epsilon3, the odds of having AD were significantly increased among those with 1 or more copies of the epsilon4 allele; the odds ratio (OR) for the epsilon3/epsilon4 genotype was 2.6 (95% confidence interval [CI], 1.8-3.7), and the OR for the epsilon4/epsilon4 genotype was 10.5 (95% CI, 5.1-21.8). These risks decreased substantially after 68 years of age. The risk for AD was lower among individuals with the epsilon2/epsilon3 genotype (OR, 0.41; 95% CI, 0.22-0.79). The patterns of association were similar in men and women. These results obtained from comparisons of unrelated AD patients and controls were bolstered by results of analysis of family data that showed preferential transmission of the epsilon4 allele to demented siblings (P<<.001) and of the epsilon2 allele to nondemented siblings (P=.005).

CONCLUSIONS

The presence of 1 or 2 epsilon4 alleles is a determinant of AD risk in African American subjects. The age-related risk for decline associated with the epsilon4 allele and the apparent protective effect of the epsilon2 allele are similar to patterns observed in white subjects.

Hippocampal atrophy correlates with clinical features of Alzheimer disease in African Americans

CONTEXT

Imaging measurements may aid in the characterization and diagnosis of patients with Alzheimer disease (AD). Most research studies, however, have been performed on predominantly white study groups despite the fact that there may be biological differences in AD between African American and white patients.

OBJECTIVE

To measure hippocampal volume in African American patients with AD and to correlate these measurements with the presence of AD and neuropsychological test performance.

DESIGN

Survey study.

SETTING

Academic center.

PARTICIPANTS

Fifty-four healthy African American subjects and 32 African American patients with AD were studied. Hippocampal volumes were measured in all subjects from magnetic resonance images using established methods.

MAIN OUTCOME MEASURE

Correlations were assessed between hippocampal volume and demographic variables, clinical group membership, and neuropsychological performance.

RESULTS

The hippocampi of patients were atrophic with respect to those of healthy subjects (P<.01). Significant direct correlations were present between hippocampal volumes and performance on several different neuropsychological tests (r>0.5 and P<.01 for every test evaluated) when patients and healthy subjects were combined.

CONCLUSIONS

Hippocampal atrophy is a feature of AD in African Americans as it is in white subjects. The neuropsychological-hippocampal volume correlations indicate that hippocampal volume measurements do represent a measure of the structural substrate of functional impairment in AD.