The Associations of Plasma/Serum Carotenoids with Alzheimer’s Disease: A Systematic Review and Meta-Analysis

Background: Multiple lines of evidence indicate protective effects of carotenoids in Alzheimer’s disease (AD). However, previous epidemiological studies reported inconsistent results regarding the associations between carotenoids levels and the risk of AD. Objective: Our study aims to evaluate the associations of six major members of carotenoids with the occurrence of AD by conducting a systematic review and meta-analysis. Methods: Following PRISMA guidelines, a comprehensive literature search of PubMed, Web of Science, Ebsco, and PsycINFO databases was conducted, and the quality of each included studies was evaluated by a validated scoring systems. Standardized mean differences (SMD) with 95%confidence intervals (CI) were determined by using a random effects model. Heterogeneity was evaluated by I2 statistics. Publication bias was detected using funnel plots and Egger’s test. Results: Sixteen studies, with 10,633 participants were included. Pooled analysis showed significantly lower plasma/serum levels of lutein (SMD = –0.86, 95%CI: –1.67 to –0.05, p = 0.04) and zeaxanthin (SMD = –0.59; 95%CI: –1.12 to –0.06, p = 0.03) in patients with AD versus cognitively intact controls, while α-carotene (SMD = 0.21, 95%CI: –0.68 to 0.26, p = 0.39), β-carotene (SMD = 0.04, 95%CI: –0.57 to 0.65, p = 0.9), lycopene (SMD = –0.12, 95%CI: –0.96 to 0.72, p = 0.78), and β-cryptoxanthin (SMD = –0.09, 95%CI: –0.83 to 0.65, p = 0.81) did not achieve significant differences. Conclusion: Of six major members of carotenoids, only lutein and zeaxanthin concentrations in plasma/serum were inversely related to the risk of AD. More high-quality longitudinal studies are needed to verify these findings.

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Efficacy and Safety of Psychostimulants for Alzheimer’s Disease: A Systematic Review and Meta-Analysis

Pharmacopsychiatry ◽

10.1055/a-1076-8228 ◽

2020 ◽

Vol 53 (03) ◽

pp. 109-114

Author(s):

Taro Kishi ◽

Kenji Sakuma ◽

Nakao Iwata

Keyword(s):

Systematic Review ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mmse Score ◽

Meta Analysis ◽

Double Blind ◽

Treatment Groups ◽

Interview Score ◽

Mean Differences ◽

State Examination

Abstract Introduction Several reports of the effectiveness of the use of psychostimulants for the treatment of Alzheimer’s disease (AD) are available. Methods A systematic review and meta-analysis was conducted including double-blind, randomized, placebo-controlled trials. Outcomes were the improvement of apathy scales score (primary), mini-mental state examination (MMSE) score, activities of daily living scale score, Zarit burden interview score, all-cause discontinuation, discontinuation due to adverse events, and incidence of at least 1 adverse event. Results Three methylphenidate studies and 1 modaﬁnil study were identified (n=156). Results from combined psychostimulants were superior to placebo in the improvement of apathy scales score (standardized mean differences [SMD]=−0.63 (−1.22, −0.04), p=0.04, all studies) and the MMSE score (SMD=−0.58 (−1.14, −0.02), p=0.04, 3 methylphenidate studies). The modaﬁnil study was excluded from the meta-analysis for the improvement of apathy scales score; therefore, the effect size increased (SMD=−0.82 (−1.43, −0.20), p=0.009). However, no significant differences were observed in terms of other outcomes, including safety outcomes between the treatment groups. Discussion Methylphenidate would be effective in treating apathy and cognitive impairment in AD patients.

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Serum Ghrelin in Mild Cognitive Impairment and Alzheimer's Disease A Systematic Review and Meta-analysis

10.21203/rs.3.rs-490560/v1 ◽

2021 ◽

Author(s):

Xiaodong Chen ◽

Yunfeng Luo

Keyword(s):

Systematic Review ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Meta Analysis ◽

Serum Levels ◽

Cochrane Library ◽

Significant Heterogeneity ◽

Serum Ghrelin

Abstract Background Serum ghrelin levels have been reported to be altered in Alzheimer’s disease (AD) patients and individuals with Mild cognitive impairment (MCI). However, whether serum ghrelin can be used as a biomarker of AD is inconsistent and conflicting. Methods We carried out a systematic review and meta-analysis to examine the serum levels of ghrelin and acylated ghrelin (AG) in patients with AD or MCI, in comparison with normal controls (NC). We searched PubMed, The Cochrane Library, Web of Science and Chinese National Knowledge Infrastructure (CNKI) from 1999 to March 2021. Results 10 relevant studies were included for this study. 8 studies reported serum levels of ghrelin (417 AD or MCI patients and 382 controls) and 5 studies reported serum levels of AG (142 AD or MCI patients and 152 controls). We found that AD and MCI patients had a tendency toward a decrease in the serum levels of ghrelin (SMD=-1.04; 95%CI (-2.30, 0.23); P = 0.11; significant heterogeneity: I2 = 98%), but no statistical significance was found. AG levels in the serum level of AD and MCI patients were significantly higher than NC subjects (SMD = 0.99; 95%CI (0.21, 1.77); P = 0.01; significant heterogeneity: I2 = 87%). Conclusion This meta-analysis suggested that AG may be a potential MCI or early AD biomarker and confirmed previous findings that ghrelin became desensitized in AD patients. This meta-analysis was limited to small sample sizes and lacked of stratifying the level of heterogeneity in AD and MCI patients. More and large sample, multi-center case-control studies on the relationship between serum AG and AD or MCI patients are still needed in the future.

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Investigating Auditory Electrophysiological Measures of Participants with Mild Cognitive Impairment and Alzheimer’s Disease: A Systematic Review and Meta-Analysis of Event-Related Potential Studies

Journal of Alzheimer s Disease ◽

10.3233/jad-210556 ◽

2021 ◽

pp. 1-30

Author(s):

Hadeel Y. Tarawneh ◽

Wilhelmina H.A.M. Mulders ◽

Hamid R. Sohrabi ◽

Ralph N. Martins ◽

Dona M.P. Jayakody

Keyword(s):

Systematic Review ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Meta Analysis ◽

Pooled Analysis ◽

Event Related Potential ◽

P300 Amplitude ◽

Related Potentials

Background: Objectively measuring auditory functions has been proposed as an avenue in differentiating normal age-related cognitive dysfunction from Alzheimer’s disease (AD) and its prodromal states. Previous research has suggested auditory event-related potentials (AERPs) to be non-invasive, cost-effective, and efficient biomarkers for the diagnosis of AD. Objective: The objective of this paper is to review the published literature on AERPs measures in older adults diagnosed with AD and those at higher risk of developing AD, i.e., mild cognitive impairment (MCI) and subjective cognitive decline. Methods: The search was performed on six major electronic databases (Ovid MEDLINE, OVID EMBASE, PsycINFO, PubMed, Scopus, and CINAHL Plus). Articles identified prior to 7 May 2019 were considered for this review. A random effects meta-analysis and analysis of between study heterogeneity was conducted using the Comprehensive Meta-Analysis software. Results: The search identified 1,076 articles; 74 articles met the full inclusion criteria and were included in the systematic review, and 47 articles were included into the analyses. Pooled analysis suggests that AD participants can be differentiated from controls due to significant delays in ABR, N100, P200, N200, and P300 latencies. P300 amplitude was significantly smaller in AD participants compared to controls. P300 latencies differed significantly between MCI participants and controls based on the pooled analysis. Conclusion: The findings of this review indicate that some AERPs may be valuable biomarkers of AD. In conjunction with currently available clinical and neuropsychological assessments, AERPs can aid in screening and diagnosis of prodromal AD.

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Faculty Opinions recommendation of Late-life depression and risk of vascular dementia and Alzheimer's disease: systematic review and meta-analysis of community-based cohort studies.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718009150.793476303 ◽

2013 ◽

Author(s):

Craig Ritchie ◽

Abel Koshy

Keyword(s):

Systematic Review ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cohort Studies ◽

Vascular Dementia ◽

Meta Analysis ◽

Late Life ◽

Late Life Depression ◽

Community Based

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Effect of antihypertensive drugs on cognition and behavioral symptoms of patients with Alzheimer’s disease: A meta-analysis

Current Pharmaceutical Biotechnology ◽

10.2174/1386207323666201211101720 ◽

2020 ◽

Vol 21 ◽

Author(s):

Roja Rahimi ◽

Shekoufeh Nikfar ◽

Masoud Sadeghi ◽

Mohammad Abdollahi ◽

Reza Heidary Moghaddam ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Randomized Clinical Trials ◽

Antihypertensive Drugs ◽

Meta Analysis ◽

Behavioral Symptoms ◽

Cochrane Library ◽

Mean Differences ◽

Global Impression Of Change ◽

State Examination

Background: It has been found that there is a link between hypertension and elevated risk of Alzheimer’s disease (AD). Herein, a meta-analysis based on randomized clinical trials (RCTs) was used to assess the effect of antihypertensive drugs on cognition and behavioral symptoms of AD patients. Method: The three databases – PubMed/Medline, Scopus, and Cochrane Library- were searched up to March 2020. The quality of the studies included in the meta-analysis was evaluated by the Jadad score. Clinical Global Impression of Change (CGIC) included in two studies, Mini-Mental State Examination (MMSE) included in three studies, and Neuropsychiatric Inventory (NPI) in three studies were the main outcomes in this systematic review. Results: Out of 1506 studies retrieved in the databases, 5 RCTs included and analyzed in the meta-analysis. The pooled mean differences of CGIC, MMSE, and NPI in patients with AD receiving antihypertensive drugs compared to placebo was -1.76 with (95% CI = -2.66 to -0.86; P=0.0001), 0.74 (95% CI = 0.20 to 1.28; P= 0.007), and -9.49 (95% CI = -19.76 to 0.79; P = 0.07), respectively. Conclusion: The findings of the present meta-analysis show that antihypertensive drugs may improve cognition and behavioral symptoms of patients with AD. However, more well-designed RCTs with similar drugs are needed to achieve more conclusive results.

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