Relationship between folate, vitamin B12, homocysteine, transaminase and mild cognitive impairment in China: a case-control study.

To explore the association between the levels of serum folate, vitamin B12, and homocysteine (Hcy), transaminase and mild cognitive impairment (MCI) in Chinese elderly. A case-control study was implemented between April and October 2016. Elderly participants aged ≥60 with and without MCI (n = 118 separately) were recruited from Community Health Center of Binhai New Area in Tianjin. Spearman's correlation analysis indicated that Hcy was significantly positively correlated with alanine transaminase (ALT) and aspartate aminotransferase (AST), and negative correlations were found among Hcy, Mini-Mental Status Examination score, Wechsler Adult Intelligence Scale-Revised by China intelligence quotient, folate and vitamin B12. The associations among MCI and folate, vitamin B12, Hcy and transaminase were assessed using multivariate logistic regression analyses. Lower folate levels and higher Hcy and ALT and AST levels were associated with MCI risk adjusted for multiple covariates. Increased ALT, AST, Hcy levels and lower folate levels were independently associated with the risk of MCI.

Association of Leukocyte Telomere Length with Mild Cognitive Impairment and Alzheimer's Disease: Role of Folate and Homocysteine.

BACKGROUND: Leukocyte telomere length (LTL) is associated with the aging process and age-related degenerative diseases. The relation of peripheral blood LTL to mild cognitive impairment (MCI) and Alzheimer's disease (AD) and the role of folate and homocysteine (Hcy) in this relation remain unclear. OBJECTIVES: We aimed to investigate the association between LTL and the risks of MCI/AD, and to explore whether folate and Hcy may play a role in this association. METHODS: This case-control study included 129 MCI subjects, 131 AD patients and 134 healthy controls. LTL was assessed using real-time polymerase chain reaction assay. Serum folate levels were tested by chemiluminescence enzyme immunoassay, and serum Hcy levels were measured using the enzymatic cycling method. Data were analyzed using multivariate logistic regression and multivariable linear regression with adjustment for potential confounders. RESULTS: The mean LTL was 1.56 ± 0.25 in controls, 1.44 ± 0.23 in MCI, and 1.28 ± 0.28 in AD patients (p< 0.01). In multivariate logistic regression, subjects in the longest LTL tertile had lower OR for MCI (OR 0.246; 95% CI 0.101-0.597) and AD (OR 0.123; 95% CI 0.044-0.345) in comparison to subjects in the shortest tertile. Shorter LTL was dose-dependently related to the ORs of MCI and AD. Further, serum folate concentration was positively associated with LTL (p < 0.01), while serum Hcy level was negatively associated with LTL (p < 0.05). In stratified analyses, LTL-MCI/AD association varied by serum folate and Hcy level. CONCLUSIONS: Shorter LTL is associated with the risks of MCI/AD. Folate and Hcy might play an important role in this association.

Effects of Folic Acid and Vitamin B12, Alone and in Combination on Cognitive Function and Inflammatory Factors in the Elderly with Mild Cognitive Impairment: A Single-blind Experimental Design.

BACKGROUND: Folate and vitamin B12 are well-known as essential nutrients that play key roles in the normal functions of the brain. Inflammatory processes play at least some role in the pathology of AD. Effective nutritional intervention approaches for improving cognitive deficits that reduce the peripheral inflammatory cytokine levels have garnered special attention. OBJECTIVE: The present study aimed to determine whether supplementation with folic acid and vitamin B12, alone and in combination improves cognitive performance via reducing levels of peripheral inflammatory cytokines. METHODS: 240 participants with MCI were randomly assigned in equal proportion to four treatment groups: folic acid alone, vitamin B12 alone, folic acid plus vitamin B12 or control without treatment daily for 6 months. Cognition was measured with WAIS-RC. The levels of inflammatory cytokines were measured using ELISA. Changes in cognitive function or blood biomarkers were analyzed by repeatedmeasure analysis of variance or mixed-effects models. This trial has been registered with trial number ChiCTR-ROC-16008305. RESULTS: Compared with control group, the folic acid plus vitamin B12 group had significantly greater improvements in serum folate, homocysteine, vitamin B12 and IL-6, TNF-α, MCP-1. The folic acid plus vitamin B12 supplementation significantly changed the Full Scale IQ (effect size d = 0.169; P = 0.024), verbal IQ (effect size d = 0.146; P = 0.033), Information (d = 0.172; P = 0.019) and Digit Span (d = 0.187; P = 0.009) scores. Post hoc Turkey tests found that folic acid and vitamin B12 supplementation was significantly more effective than folic acid alone for all endpoints. CONCLUSIONS: The combination of oral folic acid plus vitamin B12 in MCI elderly for six months can significantly improve cognitive performance and reduce the levels of inflammatory cytokines in human peripheral blood. The combination of folic acid and vitamin B12 was significantly superior to either folic acid or vitamin B12 alone.

Association of Neutrophil-Lymphocyte Ratio with Mild Cognitive Impairment in Elderly Chinese Adults: A Case-control Study.

BACKGROUND: Inflammation plays a significant role in the pathophysiology of cognitive impairment in previous studies. Neutrophil-lymphocyte ratio (NLR) is a reliable measure of systemic inflammation. OBJECTIVES: The aim of this study was to investigate the association between NLR and mild cognitive impairment (MCI), and further to explore the diagnostic potential of the inflammatory markers NLR for the diagnosis of MCI in elderly Chinese individuals. METHODS: 186 MCI subjects and 153 subjects with normal cognitive function were evaluated consecutively in this study. Neutrophil (NEUT) count and Lymphocyte (LYM) count were measured in fasting blood samples. The NLR was calculated by dividing the absolute NEUT count by the absolute LYM count. Multivariable logistic regression was used to evaluate the potential association between NLR and MCI. NLR for predicting MCI was analyzed using Receiver Operating Characteristic (ROC) curve analysis. RESULTS: The NLR of MCI group was significantly higher than that of subjects with normal cognitive function (2.39 ± 0.55 vs. 1.94 ± 0.51, P < 0.001). Logistic regression analysis showed that higher NLR was an independent risk factor for MCI (OR: 4.549, 95% CI: 2.623-7.889, P < 0.001). ROC analysis suggested that the optimum NLR cut-off point for MCI was 2.07 with 73.66% sensitivity, 69.28% specificity, 74.48% Positive Predictive Values (PPV) and 68.36% negative predictive values (NPV). Subjects with NLR ≥ 2.07 showed higher risk relative to NLR < 2.07 (OR: 5.933, 95% CI: 3.467-10.155, P < 0.001). CONCLUSION: The elevated NLR is significantly associated with increased risk of MCI. In particular, NLR level higher than the threshold of 2.07 was significantly associated with the probability of MCI.