| Part I. Habitual coffee consumption and risk of cognitive decline/dementia:a meta-analysisObjective:With the development of population aging, the incidence of cognitive decline or dementia is increasing. And the diseases burden is getting heavier. Healthy eating and proper nutrition in cognitive impairment and dementia also plays an important role in primary prevention. Findings from epidemiologic studies of coffee consumption and risk for cognitive decline or dementia are inconclusive. The aim of this study was to conduct a meta-analysis of prospective studies to assess the association between coffee consumption and the risk for cognitive decline and dementia.Methods:Relevant studies were identified by searching PubMed and Embase databases between 1966 and December 2014. Prospective cohorts that reported relative risk (RRs) and 95% confidence intervals (CIs) for the association of coffee consumption with dementia incidence or cognitive changing were eligible. Study-specific RRs were combined by using a random-effects model.Results:Eleven prospective studies, including 29,155 participants, were included in the meta-analysis. The combined RR indicated that high coffee consumption was not associated with the different measures of cognitive decline or dementia (summary RR,0.97; 95% CI,0.84-1.11). Subgroup analyses suggested a significant inverse association between highest coffee consumption and the risk for Alzheimer disease (summary RR,0.73; 95% CI,0.55-0.97). The dose-response analysis, including eight studies, did not show an association between the increment of coffee intake and cognitive decline or dementia risk (an increment of 1 cup/d of coffee consumed; summary RR,1.00; 95% CI,0.98-1.02).Conclusions:The present study suggests that higher coffee consumption is associated with reduced risk for Alzheimer disease. Further randomized controlled trials or well-designed cohort studies are needed to determine the association between coffee consumption and cognitive decline or dementia.Part II. The influence of green tea intake and angiotensin converting enzyme genetic polymorphism on mild cognitive impairment in patient with cerebral small vessel diseaseObjective:Cerebral small vessel disease (CSVD) is an important cause of cognitive impairment among the elderly. CSVD firstly led to subsequent declines in executive function and then progress into subcortical type mild cognitive impairment (MCI), and finally develop to subcortical vascular dementia. Green tea intake is associated with the reducing of dementia risk. In addition, the angiotensin converting enzyme (ACE) may have an effect in vascular dementia and Alzheimer’s disease. Moreover, ACE signaling pathway may be the primary mediator in the tea-dementia. However, the pertinent mechanisms are only restricted to in vitro and animal in vivo studies and lack of evidence from molecular epidemiological study. We thus use the population case-control design to investigate the association of ACE polymorphisms (SNPs), dietary green tea intake, and their potential interactions with the MCI risk in CSVD patients. We believed that our findings will provide guidelines for MCI primary prevention in CSVD patients, as well as the clues to the biological mechanisms of MCI in patient with CSVD.Methods:Case-control study and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method were used to detect the polymorphisms of ACE gene in 142 mild cognitive impairment in patient with cerebral small vessel disease and 140 healthy controls. A set of neuropsychological assessment scale include:Mini-Mental State Examination (MMSE), The Montreal Cognitive Assessment (MoCA), Clock Drawing Task (CDT), Symbol digit modalities test, Digit span total numbers recalled, Reversed digit span total numbers recalled, Rey Auditory Verbal Learning Test (RAVLT), Trail Making Test A and B (TMT-A, TMT-B), Phonetic Verbal Fluency Test (VFT).Results:The scores of MMSE (22.37±3.00 vs.26.70±1.41), MoCA (21.30±3.27 vs. 25.57±1.30), CDT (3.15±0.99 vs.4.0±0.00), SDMT (30.53±12.71 vs.33.64±6.39), DST (3.41±1.01 vs.4.14±0.92), VFT (23.83±5.59 vs.27.71±5.76), AVLT (5min) (5.72±3.31 vs.6.64±1.45) and AVLT (20min) (5.89±4.06 vs.6.77±2.26) in MCI group were significantly lower than the health control group (P<0.05). The scores of TMT-A (81.43±30.10 vs.75.22±19.39) and TMT-B (176.21±50.99 vs.145.36±42.17) were significantly higher than the health control group (P<0.05). After adjusting the established and potential confounders, green tea consumption was associated with a reduced risk of MCI in patients with CSVD, with an adjusted odds ratio (OR) of 0.80 (95% confidence interval,0.50-1.29) compared with those who did notdrink green tea. Compared to non-tea drinkers, the adjusted ORs were 1.22 (0.47-3.20) in male patients consuming less than 125 g of dried green tea leaves per month,0.32 (0.13-0.81) for 125-249 g per month and 0.51 (0.22-1.20) for≥250 g per month, with a statistically significant test for trend (P=0.013). The distribution of ACEI/D genotype followed Hardy-Weinberg equilibrium among MCI patients and control subjects (P>0.05 for each comparison). Our data showed that the distribution of ACEI/D alleles and genotypes were not significantly different in patients compared with controls. Interactions between genetic and environmental revealed that green tea intake and ACEI/D did not effect on the mild cognitive impairment in patients with CSVD.Conclusions:The cognitive function of MCI in CSVD included impairment in memory, attention, Visual-spatial, executive function, and so many obstacles cognitive areas. Green tea consumption could protect against the development of MCI in patients with CSVD. No association was found between ACEI/D and MCI in patients with CSVD. Interactions between green tea intake and ACEI/D did not effect on the mild cognitive impairment in patients with CSVD. |
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