Qu M, Shi H, Wang K, Wang X, Yu N, Guo B. The Associations of Plasma/Serum Carotenoids with Alzheimer's Disease: A Systematic Review and Meta-Analysis.
J Alzheimers Dis 2021;
82:1055-1066. [PMID:
34151808 DOI:
10.3233/jad-210384]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
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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