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Background: White matter hyperintensities (WMHs) are strongly linked to cardiovascular risk factors and other health conditions such as Alzheimer's disease. However, there is a dearth of research on this topic in low-income countries and underserved populations, especially in the Democratic Republic of Congo (DRC) where the population is aging rapidly with increasing cardiovascular risk factors and dementia-related diseases. This study evaluates health factors associated with WMH in the elderly Sub-Saharan Africa (SSA), specifically Congolese adults. Methods: In a cross-sectional study of 77 people from the DRC, participants underwent neuroimaging to analyze WMH volume and completed clinical evaluation, laboratory-based blood exams, self-reported questionnaires, and interviews. A simple linear regression model was conducted to test the association between WMH and potential predictors (neurological status, age, sex, hypertension, diabetes, tobacco abuse, stroke, high cholesterol, cardiovascular medication, and alcohol abuse). Stepwise selection and backward elimination analyses were performed to obtain the final model. Finally, a multiple linear regression model was conducted to assess the association between WMH and variables retained in the final model (neurological status, sex, and age). Results: Of the 77 individuals, 47 (61%) had dementia, 40 (52.6%) were males, and the mean age was 73 years (± 8.0 years standard deviation). In simple linear regression models, WMH was significantly associated with dementia (expß1=1.75, 95% CI=1.14 - 2.71, p-value=0.01) though it had a weak association with age (expß1=1.03, 95% CI=1.00 - 1.05, p-value=0.05) and sex (male) (expß1=0.66, 95% CI=0.43 - 1.01, p-value=0.05). In multiple linear regression models, WMH was statistically significantly associated with dementia (expß1=1.97, 95% CI=1.31 - 2.95, p-value =0.001), male sex (expß2=0.54, 95% CI=0.36 - 0.80, p-value=0.003), and age (expß3=1.03, 95% CI=1.00 - 1.06, p-value=0.03). However, WMH was not significantly associated with common cardiovascular risk factors, such as high blood pressure, diabetes, tobacco use, obesity, and high cholesterol levels. Conclusion: WMH is significantly associated with neurological status, sex, and age in the Congolese population. Understanding these predictors may improve our ability to diagnose, assess, and develop preventative treatments for white matter disease in SSA/DRC populations, where neuroimaging is difficult to obtain.
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Background: The current study examined the sensitivity of two memory subtests and their corresponding learning slope metrics derived from the African Neuropsychology Battery (ANB) to detect amyloid pathology and APOEε4 status in adults from Kinshasa, the Democratic Republic of the Congo. Methods: 85 participants were classified for the presence of ß-amyloid pathology and based on allelic presence of APOEε4 using Simoa. All participants were screened using CSID and AQ, underwent verbal and visuospatial memory testing from ANB, and provided blood samples for plasma Aß42, Aß40, and APOE proteotype. Pearson correlation, linear and logistic regression were conducted to compare amyloid pathology and APOEε4 status with derived learning scores, including initial learning, raw learning score, learning over trials, and learning ratio. Results: Our sample included 35 amyloid positive and 44 amyloid negative individuals as well as 42 without and 39 with APOEε4. All ROC AUC ranges for the prediction of amyloid pathology based on learning scores were low, ranging between 0.56-0.70 (95% CI ranging from 0.44-0.82). The sensitivity of all the scores ranged between 54.3-88.6, with some learning metrics demonstrating good sensitivity. Regarding APOEε4 prediction, all AUC values ranged between 0.60-0.69, with all sensitivity measures ranging between 53.8-89.7. There were minimal differences in the AUC values across learning slope metrics, largely due to the lack of ceiling effects in this sample. Discussion: This study demonstrates that some ANB memory subtests and learning slope metrics can discriminate those that are normal from those with amyloid pathology and those with and without APOEε4, consistent with findings reported in Western populations.
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Background: Western countries have provided reference values (RV) for Alzheimer's disease (AD) plasma biomarkers, but there are not available in Sub-Saharan African populations. Objective: We provide preliminary RV for AD and other plasma biomarkers including amyloid- ß (Aß42/40), phosphorylated tau-181 and 217 (p-tau181, p-tau217), neurofilament light (Nfl), glial fibrillary acidic protein (GFAP), interleukin 1b and 10 (IL-1b and IL-10) and tumor necrosis factor α (TNFα) in Congolese adults with and without dementia. Methods: 85 adults (40 healthy and 45 dementia) over 50 years old were included. Blood samples were provided for plasma AD biomarkers Aß42/40 and p-tau181, p-tau217; Nfl and GFAP; IL-1b and IL-10 and TNFα analyzed using SIMOA. Linear and logistic regressions were conducted to evaluate differences in biomarkers by age and gender and neurological status, and for the prediction of dementia status by each individual biomarker. RV were those that optimized sensitivity and specificity based on Youden's index. Results: In this sample of 85 adults, 40 (47%) had dementia, 38 (45.0%) were male, overall mean age was 73.2 (SD 7.6) years with 8.3 (5.4) years of education. There were no significant differences in age, gender, and education based on neurological status. Biomarker concentrations did not significantly differ by age except for p-tau181 and GFAP and did not differ by sex. Preliminary cutoffs of various plasma in pg/ml were 0.061 for Aß42/40, 4.50 for p-tau 181, 0.008 for p-tau 217, 36.5 for Nfl, 176 for GFAP, 1.16 for TNFa, 0.011 for IL-1b, and 0.38 for IL-10. All AUCs ranged between 0.64-0.74. P-tau 217 [0.74 (0.61, 0.86)] followed by GFAP [0.72 (0.61, 0.83), and Nfl [0.71 (0.60, 0.82)] had the highest AUC compared to other plasma biomarkers. Conclusions: This study provides RV which could be of preliminary utility to facilitate the screening, clinical diagnostic adjudication, classification, and prognosis of AD in Congolese adults.
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Objective: The hippocampus is one of the first brain structures affected by Alzheimer's disease (AD), and its atrophy is a strong indicator of the disease. This study investigates the ability of plasma biomarkers of AD and AD-related dementias-amyloid-ß (Aß42/40), phosphorylated tau-181 (p-tau181), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP)-to predict hippocampal atrophy in adult individuals in Kinshasa, Democratic Republic of Congo (DRC). Methods: Eighty-five adult individuals (40 healthy and 45 suspected AD) over 65 years old were evaluated using the Community Screening Instrument for Dementia and Alzheimer's Questionnaire (AQ). Core AD biomarkers (Aß42/40 and p-tau181) and non-specific neurodegeneration biomarkers (NfL, GFAP) were measured in blood samples collected at the study visit. Hippocampal volumes were measured using magnetic resonance imaging (MRI). General linear regression was used to evaluate differences in biomarker concentrations by neurological status. Logistic regression models were used to create receiver operating characteristic curves and calculate areas under the curve (AUCs) with and without clinical covariates to determine the ability of biomarker concentrations to predict hippocampal atrophy. Plasma biomarkers were used either individually or in combination in the models. Results: Elevated p-tau181 was associated with left hippocampal (LH) atrophy p= 0.020). Only higher p-tau181 concentrations were significantly associated with 4.2-fold increased odds [OR=4.2 (1.5-18.4)] of hippocampal atrophy per standard deviation. The AUC of plasma biomarkers without clinical covariates to discriminate LH, RH, and total hippocampal (TH) or both hippocampi atrophy ranged between 90% to 94%, 76% to 82%, and 85% to 87%, respectively. The AUC of models including clinical covariates and AD biomarkers used in combination to discriminate LH, RH, and TH ranged between 94%-96%, 81%-84%, and 88%-90%, respectively. Conclusion: These results indicate that, consistent with studies in other settings, core AD plasma biomarkers can predict hippocampal atrophy in a population in Sub-Saharan Africa.
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Introduction: This study investigates whether plasma biomarkers (Aß42/40 and p-tau 181), APS, as well as apolipoprotein E (APOE) proteotype predict cognitive deficits in elderly adults from the Democratic Republic of Congo. Methods: Forty-four with possible AD (pAD) and 41 healthy control (HC) subjects were screened using CSID and AQ, underwent cognitive assessment with the African Neuropsychology Battery (ANB), and provided blood samples for plasma Aß42, Aß40, Aß42/40, and APOE proteotype. Linear and logistic regression were used to evaluate the associations of plasma biomarkers with ANB tests and the ability of biomarkers to predict cognitive status. Results: Patients with pAD had significantly lower plasma Aß42/40 levels, higher APS, and higher prevalence of APOE E4 allele compared to HC. Groups did not differ in levels of Aß40, Aß42, or P-tau 181. Results showed that Aß42/40 ratio and APS were significantly associated with African Naming Test (ANT), African List Memory Test (ALMT), and African Visuospatial Memory Test (AVMT) scores, while the presence of APOE E4 allele was associated with ANT, ALMT, AVMT, and APT scores. P-tau 181 did not show any significant associations while adjusting for age, education, and gender. APS showed the highest area under the curve (AUC) value (AUC = 0.78, 95% confidence interval [CI]: 0.68-0.88) followed by Aß42/40 (AUC = 0.75, 95% CI: 0.66-0.86) and APOE E4 (AUC = 0.69 (CI 0.57-0.81) in discriminating pAD from HC. Discussion: These results demonstrate associations between select plasma biomarker of AD pathology (Aß42/40), APS, and APOE E4 allele) and ANB test scores and the ability of these biomarkers to differentiate pAD from cognitively normal SSA individuals, consistent with findings reported in other settings.
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OBJECTIVE: In light of the increased longevity of people living with HIV infection (PLWH) undergoing antiretroviral therapy (ART), the present study aimed to determine the effects of mood disturbances alongside cognitive and motor symptoms on activities of daily living (ADLs) and quality of life (QOL) in older PLWH in comparison to an aging control sample without notable medical history (CTL) and individuals with Parkinson's disease (PD). METHOD: Forty-one PLWH, 41 individuals with PD, and 37 CTL, aged 45-79 years, underwent neuropsychological, psychological, and neurological assessment including depressive and anxiety symptoms, physical (ADL-p) and instrumental (ADL-i) daily activities, Unified Parkinson's Disease Rating Scale motor ADLs (ADL-UPDRS-II), QOL, and cognitive and motor functions. Hierarchical regression analyses assessed the relative contribution of predictors including demographics, disease-related factors, comorbid conditions, and mood-related factors for ADL and QOL scales. RESULTS: PLWH and PD participants reported more depressive symptoms and higher anxiety and worse QOL and ADL-i than CTL. The PD group had greater ADL-p and motor-related ADL-UPDRS-II difficulties than PLWH and CTL groups. In PLWH, medical comorbidities and alcohol use disorder (AUD)/substance use disorder (SUD) histories significantly contributed to poor physical and motor ADLs. Mood scores, particularly depressive symptoms, were independent predictors of poor QOL and most ADLs in both clinical groups, above the contribution of cognitive compromise. CONCLUSIONS: Mood symptoms contribute significantly to poor ADLs and QOL in people aging with chronic diseases such as long-term HIV infection and PD. Comprehensive assessment and treatment of mood symptoms are recommended for ensuring optimal functional independence and life quality. (PsycInfo Database Record (c) 2022 APA, all rights reserved).