A meta-analysis of peripheral tocopherol levels in age-related cognitive decline and Alzheimer's disease. (3rd October 2021)

• Record Type: Journal Article
• Authors: Ashley, Stephanie; Bradburn, Steven; Murgatroyd, Chris
• Is Part Of: Nutritional neuroscience. Volume 24:Number 10(2021)
• Page Start: 795
• Page End: 809
• Publication Date: 2021-10-03
• Subjects: Vitamin E -- α-tocopherol -- γ-tocopherol -- Alzheimer's disease -- MCI -- diet -- meta-analysis; Neuropharmacology -- Periodicals; Diet -- Periodicals; Diet therapy -- Periodicals; Nutrition -- Periodicals; 615.78
• DOI: 10.1080/1028415X.2019.1681066
• Languages: English
• ISSNs: 1028-415X

Abstract

ABSTRACT: Objectives: Findings from observational studies and clinical trials on the associations between vitamin E and dementia remain controversial. Here we conducted a meta-analysis to determine the difference in blood tocopherols levels between patients with Alzheimer's disease (AD) or age-related poor cognitive function and healthy controls. Methods: Standardised mean difference (SMD) and 95% confidence intervals (CIs) were calculated and entered into a random effects model. Study quality, heterogeneity and publication bias were also investigated. Results: Thirty-one articles were included in the meta-analysis, which included analyses for α -, β -, γ - and δ -tocopherols. These results indicated that individuals with AD or age-related cognitive deficits and mild cognitive impairment (MCI) had lower circulatory concentrations of α -tocophenol compared with healthy controls (AD: SMD = −0.97, 95% confidence interval [CI] = −1.27 to −0.68, Z = 6.45, P < 0.00001; age-related cognitive deficits and MCI: SMD = −0.72, 95% CI = −1.12 to −0.32, Z = −3., P < 0.0005). Levels of β -, γ - and δ -tocophenols did not significantly differ between groups of AD and age-related cognitive deficits compared to controls. Discussion: These results suggest that lower α -tocopherol levels have a strong association with AD and MCI supporting evidence for the role of diet and vitamin E in AD risk and age-related cognitive decline.