AD患者血清Hcy叶酸及维生素B_(12)与认知功能减退的关系研究

目的研究维生素B_(12)和叶酸水平以及同型半胱氨酸是否对阿尔茨海默症(AD)患者存在潜在影响。方法运用美国国立神经病学、语言障碍和卒中-阿尔茨海默病和相关疾病学会(NINCDS-ADRDA)标准严格筛选AD患者95例。从体检中心选取年龄、性别及受教育程度匹配的无脑血管病、无认知障碍的健康对照组76例。采用化学发光微粒子免疫分析法检测171例年龄≥50岁的老年痴呆患者血清维生素B_(12)和叶酸水平。采用肝素抗凝的血浆进行循环酶法Hcy测定。探讨血清低水平维生素B_(12)和叶酸以及高水平同型半胱氨酸是否是老年痴呆发生的危险因素。认知功能的评价采用目前通用的神经心理测试:中文版简易精神状态检查表(MMSE)。采用Logistic回归分析评估血清维生素B_(12)、叶酸以及同型半胱氨酸与老年痴呆患病风险的关系。结果 171例中153例叶酸正常,其中对照组79例(51.63%),实验组74例(43.27%);124例维生素B_(12)正常,其中对照组60例(48.39%),实验组64例(51.61%);101例同型半胱氨酸正常,其中对照组51例(50.50%),实验组50例(49.50%)。作各协变量调整后,AD患者血清维生素B_(12)及叶酸水平以及同型半胱氨酸与CMMES评分无相关性(P0.05)。但低血清维生素B_(12)水平以及低叶酸水平与AD患病风险相关。结论血清维生素B_(12)和叶酸水平以及同型半胱氨酸水平与AD患者认知功能之间无明显关联。低水平维生素B_(12)以及低水平叶酸可能通过某种机制增加AD患病风险,低水平同型半胱氨酸可能通过某种机制降低AD患病风险。     

Vitamin B(12) and folate in relation to the development of Alzheimer's disease

OBJECTIVE: To explore the associations of low serum levels of vitamin B(12) and folate with AD occurrence. METHODS: A population-based longitudinal study in Sweden, the Kungsholmen PROJECT: A random sample of 370 nondemented persons, aged 75 years and older and not treated with B(12) and folate, was followed for 3 years to detect incident AD cases. Two cut-off points were used to define low levels of vitamin B(12) (< or =150 and < or =250 pmol/L) and folate (< or =10 and < or =12 nmol/L), and all analyses were performed using both definitions. AD and other types of dementia were diagnosed by specialists according to DSM-III-R criteria. RESULTS: When using B(12) < or =150 pmol/L and folate < or =10 nmol/L to define low levels, compared with people with normal levels of both vitamins, subjects with low levels of B(12) or folate had twice higher risks of developing AD (relative risk [RR] = 2.1, 95% CI = 1.2 to 3.5). These associations were even stronger in subjects with good baseline cognition (RR = 3.1, 95% CI = 1.1 to 8.4). Similar relative risks of AD were found in subjects with low levels of B(12) or folate and among those with both vitamins at low levels. A comparable pattern was detected when low vitamin levels were defined as B(12) < or =250 pmol/L and folate < or =12 nmol/L. CONCLUSIONS: This study suggests that vitamin B(12) and folate may be involved in the development of AD. A clear association was detected only when both vitamins were taken into account, especially among the cognitively intact subjects. No interaction was found between the two vitamins. Monitoring serum B(12) and folate concentration in the elderly may be relevant for prevention of AD.     

Correlations between cognitive, behavioural and psychological findings and levels of vitamin B12 and folate in patients with dementia

BACKGROUND: Associations between low levels of folate and vitamin B12 and cognitive impairment in patients with dementia have been reported. Some studies revealed correlations between low levels of vitamin B12 and behavioural and psychological signs and symptoms of dementia (BPSD) in Alzheimer's disease (AD) patients. Given the lack of studies in frontotemporal dementia (FTD) and on folate and given the methodological shortcomings of former publications, we set up a prospective study. METHODS: At inclusion, AD (n=152) and FTD (n=28) patients underwent a neuropsychological examination. Behaviour was assessed using a battery of behavioural assessment scales. Determination of serum vitamin B12 and red cell folate levels were performed within a time frame of two weeks of inclusion. RESULTS: In both patient groups, significantly negative correlations between levels of serum vitamin B12 and red cell folate and the degree of cognitive deterioration were found. No correlations with BPSD were found in the AD patient group. In FTD patients, levels of vitamin B12 were negatively correlated with both hallucinations (p=0.022) and diurnal rhythm disturbances (p=0.036). CONCLUSIONS: The observed negative correlations between levels of vitamin B12 and folate and cognitive impairment in both AD and FTD patients, raise the possibility of a non-specific etiological role. Although levels of vitamin B12 and folate did not correlate with BPSD in AD patients, negative correlations between serum vitamin B12 levels and BPSD in FTD patients were revealed. Decreased serum vitamin B12 levels may predispose FTD patients to develop hallucinations and diurnal rhythm disturbances.     

Neuropsychology of vitamin B12 deficiency in elderly dementia patients and control subjects

Cobalamin deficiency may cause cognitive deficits and even dementia. In Alzheimer's disease, the most frequent cause of dementia in elderly persons, low serum levels of vitamin B12, may be misleading. The aim of this work was to characterize the cognitive pattern of B12 deficiency and to compare it with that of Alzheimer's disease. Nineteen patients with low levels of vitamin B12 were neuropsychologically evaluated before treatment and a year later. Results were compared with those of 10 healthy control subjects. Final results suggest that there is a different pattern in both diseases. Twelve elderly patients with dementia improved with treatment. Seven elderly demented patients did not improve; they deteriorated after 1 year although their levels of cobalamin were normal. Analysis of the initial evaluation showed that the 2 groups of patients had a different neuropsychological profile. The group that improved had initially more psychotic problems and more deficits in concentration, visuospatial performance, and executive functions. They did not show language problems and ideomotor apraxia, which were present in the second group. Their memory pattern was also different. These findings suggest that cobalamin deficiency may cause a reversible dementia in elderly patients. This dementia may be differentiated from that of Alzheimer's disease by a thorough neuropsychological evaluation.     

Homocysteine and cognitive decline in healthy elderly.

Serum homocysteine is increased, and correlates inversely with cognitive scores, in Alzheimer's disease (AD), vascular dementia and "age-associated memory impairment". Elevated levels might signal accelerated cognitive decline, although this remains to be established. We therefore repeated Mini-Mental State Examinations, together with additional ADAS-Cog assessments, in 32 healthy elderly individuals to determine whether prior homocysteine levels predicted cognitive changes over a 5-year period. Homocysteine predicted follow-up cognitive scores and rate of decline in cognitive performance independently of age, sex, education, renal function, vitamin B status, smoking and hypertension (p < 0.001). Homocysteine predicted word recall (p = 0.01), orientation (p = 0.02) and constructional praxis scores (p < 0.0001). One subject, with the second highest initial homocysteine, had developed probable AD at follow-up. Fasting total serum homocysteine appears to be an independent predictor of cognitive decline in healthy elderly and exerts a maximal effect on spatial copying skills.     

Cognitive and psychiatric effects of vitamin B12 replacement in dementia with low serum B12 levels: a nursing home study

BACKGROUND: The aim of this study is to determine whether B12 replacement would ameliorate cognitive and psychiatric symptoms in elderly subjects with dementia and low serum B12 levels. METHODS: A test group (n = 28) of nursing home residents with low serum B12 levels (<250 pg/mL) and a matched comparison group (n = 28) with normal serum B12 levels (>300 pg/mL) were evaluated by blinded raters while the test group received intramuscular (IM) B12 replacement therapy. All subjects were assessed at baseline, 8 weeks, and 16 weeks with the Dementia Rating Scale, Brief Psychiatric Rating Scale, and Geriatric Depression Scale. RESULTS: Although B12 replacement produced significant improvement in hematologic and metabolic parameters, it yielded no significant effect on cognitive or psychiatric variables. A few subjects evidenced notable individual treatment responses; however, these were not statistically more frequent than in the normal B12 group. CONCLUSIONS: These results suggest that B12 replacement is unlikely to benefit cognitive or psychiatric symptoms in the vast majority of elderly dementia patients with low serum B12 levels.     

Clinical correlates of functional performance in community-dwelling Chinese older persons with mild cognitive impairment

ABSTRACTBackground: Increasing evidence suggests that functional impairment can be detected in older persons with mild cognitive impairment (MCI). This study explores the functional profiles and the clinical correlates of a population-based sample of Chinese older persons with MCI in Hong Kong.Methods: A random sample of 765 Chinese elderly subjects without dementia was recruited, of which 389 were elderly normal controls (Clinical Dementia Rating = 0), and 376 had questionable dementia (CDR = 0.5). The latter were categorized into an MCI group (n = 291) and a very mild dementia (VMD) group (n = 85). Their functional performances were measured and compared with the normal controls (NC). Multiple regression analyses investigated the associations between functional scores (Disability Assessment in Dementia) and clinical correlates (cognitive test scores, neuropsychiatric symptoms and motor signs) in the NC subjects and cognitively impaired subjects.Results: Subjects with MCI had intermediate functional performance between the NC and those with VMD. Regression analyses revealed that lower scores of cognitive tests (delayed recall and categorical verbal fluency tests), apathy, aberrant motor symptoms and parkinsonism features were associated with lower functional scores in clinically non-demented subjects. Functional scores had no correlation with age, education and medical illness burden.Conclusion: Neuropsychiatric symptoms and parkinsonism features were associated with functional impairment in the clinically non-demented elderly in the community. Assessment of these should be incorporated in the evaluation of older persons for early cognitive impairment.     

Evidence for association of anaemia with vascular dementia.

The present investigation aimed to examine associations of anaemia with dementia. Analysis of community-dwelling, elderly subjects characterized for different dementias failed to confirm a previously reported association of anaemia with Alzheimer's disease (AD) but revealed instead a significant association with vascular dementia (VAD). Nearly 45% of VAD subjects were anaemic, compared with 17% of controls. Close to one-third of all subjects with haemoglobin levels > 0.5 g/dl below reference anaemia levels had VAD. Co-existing VAD may explain previous links between AD and anaemia. The association was independent of age, dementia severity and a range of other factors including vitamin B 12 and folate levels. Anaemia can exacerbate focal cerebral ischaemia and could precipitate or amplify VAD symptoms in elderly subjects with vasculopathy.     

Homocysteine,apolipoproteine E and methylenetetrahydrofolate reductase in Alzheimer's disease and mild cognitive impairment

BACKGROUND: Alzheimer's disease (AD) is the most common dementia disorder in elderly people. Currently, the only known genetic factor associated with the development of sporadic AD is the apolipoprotein E (ApoE) 4 allele. There is a need to identify other environmental and genetic risk factors that could modulate the risk of developing sporadic AD. OBJECTIVE: To analyse the correlation between the ApoE and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and plasma homocysteine levels and vitamins (B(12) and folic acid) concentrations in serum from patients with AD and mild cognitive impairment (MCI) as compared with control group. METHODS: The study was carried out in 99 AD patients, 98 subjects with MCI and 100 healthy subjects. Diagnosis of probable AD was made according to the NINCDS-ADRDA and DSM-IV criteria. The following factors were analysed: age, gender, duration of disease, concentration of plasma total homocysteine, folic acid and vitamin B(12) in the serum and the polymorphism of MTHRF and ApoE genes. The results obtained were analysed by multivariate analysis of regression. RESULTS: We found that plasma total homocysteine is increased in AD patients (p < 0.0001) and depended on the MTHFR T/T genotype in the presence of low folate levels (p < 0.05). The increased frequency of ApoE4 allele in the AD population was independent of homocysteine, folic acid and vitamin B(12) levels and MTHFR status. CONCLUSIONS: We conclude that the concentration of plasma total homocysteine is increased in AD patients. This may be associated with the T/T genotype in the MTHFR gene; however, the distribution of the MTHRF C677T polymorphism in the Polish population does not differ in AD and controls.     

Homocysteine and holo-transcobalamin and the risk of dementia and Alzheimers disease: a prospective study

Background:  Elevated total homocysteine (tHcy) levels may be caused by vitamin B12 deficiency and are linked to Alzheimers disease (AD) in some studies, although the evidence is mixed. Another marker of vitamin B12 deficiency, holo-transcobalamin (holo-TC), has not been studied in a prospective setting.
Objective:  To investigate the association between tHcy and holo-TC and the subsequent development of dementia and AD in a prospective study.
Methods:  A sub-sample of 228 non-demented subjects was taken from the Kungsholmen Project, a population-based longitudinal study amongst persons 75+ years. tHcy and holo-TC were analysed at baseline.
Results:  Increasing tHcy levels were related to an increased risk of dementia ( n  = 83) and AD ( n  = 61) after a mean follow-up time of 6.7 years. Persons with high tHcy (the fourth quartile) had more than twice as high a risk of developing AD than persons with low tHcy, even after adjusting for confounding or mediating factors. The third quartile of holo-TC was associated with a reduced risk of AD, after adjusting for Hcy and other confounders.
Conclusions:  These results suggest that Hcy is involved in the development of dementia and AD. The role of holo-TC was less clear and this marker needs to be studied further.     

Motivational symptoms of depression mask preclinical Alzheimer's disease in elderly subjects

BACKGROUND: Althoughthe relationship between depressive disorders and Alzheimer's disease (AD) is debated, there is evidence that depression may be an early symptom of dementia. OBJECTIVE: To evaluate depression features prospectively in elderly subjects with a view to identifying a subgroup affected by preclinical AD. METHODS: We performed a cohort study on cognitive performances with a 12-month follow-up in out-patients referred to the local Neuropsychology Clinic complaining of memory problems. Two hundred and twenty-two consecutive non-demented subjects were studied using a neuropsychological battery and the Beck Depression Inventory (BDI) and assessed again 1 year later for the possible onset of cognitive impairment. Multivariate analysis was performed to detect independent predictors of dementia development among age, education, neuropsychological test scores and BDI scores and subscores. BDI subscores were obtained by dividing items into three domains corresponding to mood-related, somatic and motivation-related symptoms. RESULTS: At the time of the first evaluation, 124 of the 222 subjects were depressed according to DSM-III-R criteria. At 1 year, 31 of the 124 depressed subjects and 2 non-depressed ones had AD according to NINCDS-ADRDA criteria. Stepwise logistic regression analysis indicated that the subjects who went on to develop dementia had significantly higher total BDI scores and motivational BDI subscores. Among depressed subjects, the probability of being diagnosed with dementia during follow-up was significantly associated with a motivational BDI subscore > or = 7 (odds ratio: 3,885, 95% Cl 154-97,902). COMMENT: Close neuropsychological follow-up of depressed elderly subjects complaining of memory failure and showing apathy is recommended to detect the early stage of AD.     

Subnormal serum vitamin B12 and behavioural and psychological symptoms in Alzheimer's disease

The objective of this study was to examine whether patients with Alzheimer's disease (AD) with subnormal vitamin B12 levels show more frequent behavioural and psychological symptoms of dementia (BPSD) than AD patients with normal vitamin B12 levels. The design was a prospective case-control study. The study took place at a memory-clinic of a department of geriatric medicine in a teaching hospital. There were seventy-three consecutive outpatients with probable AD, including 61 patients with normal and 12 patients with subnormal (<200 pg/ml) vitamin B12. BPSD were measured using the subscales disturbed behaviour and mood of the Nurses' Observation Scale for Geriatric Patients (NOSGER), the Cornell Scale for Depression and the four criteria for personality change in dementia from the International Classification of Diseases (ICD-10). Controlling for dementia duration and degree of severity of the cognitive deficits, there were significant inverse associations between vitamin B12 status and ICD-10 irritability (p=0.045) and NOSGER subscale disturbed behaviour (p=0.015). Low vitamin B12 serum levels are associated with BPSD in AD. Vitamin B12 could play a role in the pathogenesis of behavioural changes in AD.     

Behavioural and psychological symptoms of Alzheimer type dementia are not correlated with plasma homocysteine concentration

BACKGROUND/AIMS: Vitamin B12 and folate deficiencies have been associated with cognitive impairment and various psychiatric symptoms but not specifically with behavioural and psychological symptoms of dementia (BPSD). A limitation of previous studies in dementia was lack of concurrent homocysteine measurement especially as it may provide a better indicator of tissue activities of these vitamins. This study was designed to clarify whether a relationship exists between plasma homocysteine concentration and BPSD. METHODS: Plasma homocysteine, serum vitamin B12 and folate were measured in 23 Alzheimer's disease (AD) patients with BPSD and 27 AD patients without BPSD as determined through the use of the Neuropsychiatric Inventory (NPI). Blood levels of measured substances were also correlated with individual NPI scores and with cumulative NPI scores for different cluster of symptoms. RESULTS: There was no significant difference (p = 0.956) in the mean plasma homocysteine levels between AD patients with BPSD (17.48 micromol/l) and AD patients without BPSD (17.34 micromol/l). Similarly, there was no significant difference between the two groups in the mean serum B12 (382.61 and 391.60 pg/ml, respectively) and folate (7.95 and 10.02 ng/ml, respectively). Mean levels for both vitamins were well within the laboratory reference range. Neither individual nor cluster NPI scores correlated significantly with plasma homocysteine. CONCLUSION: This study shows for the first time that BPSD are not associated with hyperhomocysteinaemia in Alzheimer dementia. Although previous studies have identified homocysteine as an independent risk factor in AD, the results reported here do not lend weight to an aetiological role for homocysteine specifically in BPSD.     

Neuropsychiatric symptoms in 921 elderly subjects with dementia: a comparison between vascular and neurodegenerative types

Objective: i) to describe the neuropsychiatric profile of elderly subjects with dementia by comparing vascular (VaD) and degenerative dementias, i.e. dementia with Lewy bodies (DLB) and Alzheimer’s disease (AD); ii) to assess whether the severity and type of dementia are associated with clinically relevant neuropsychiatric symptoms (CR‐NPS). Method: One hundred and thirty‐one out‐patients with VaD, 100 with DLB and 690 with AD were studied. NPS were evaluated by the neuropsychiatric inventory (NPI). Results: Vascular dementia had lower total and domain‐specific NPI scores and a lower frequency of CR‐NPS than AD and DLB, for which frequency of CR‐NPS increased significantly with disease severity, particularly in AD. Logistic regression analysis showed that a higher CDR score and a diagnosis of degenerative dementia were independently associated with CR‐NPS. Conclusion: Vascular dementia is associated less with CR‐NPS than AD and DLB. Frequency of CR‐NPS increases with disease severity in AD and, to a lesser extent, in DLB.     

Low B12 levels related to high activity of platelet MAO in patients with dementia disorders. A retrospective study

In 35 patients with Alzheimer's presenile disease (AD), 56 patients with senile dementia of the Alzheimer type (SDAT), 54 patients with vascular dementia (VD) and 10 patients with confusional states, age, vitamin B12 in serum, P-folate, B-folate and B-Hb were investigated. Platelet monoamine oxidase (MAO) and cerebrospinal fluid (CSF) levels of homovanillic acid (HVA), 5-hydroxyin-doleacetic acid and 3-methoxy-4-hydroxyphenylglycol were measured. Group differences showed that vitamin B12 levels were reduced in the group of patients with confusional states and SDAT. Five out of ten and 13 out of 56 (respectively) had vitamin B12 concentrations below the lower limit of the reference value (130 pmol/l). A negative correlation was found between B12 levels and platelet MAO activity. The findings indicate that there is a subgroup of patients with late-onset dementia that has low vitamin B12 blood concentrations. HVA levels in CSF, usually found to be reduced in AD patients, were normal in this subgroup.     

Folate, vitamin B12 and cognitive impairment in patients with Alzheimer's disease.

This study examines the relationship between folate, vitamin B12 and severity of cognitive impairment in patients with Alzheimer's disease (AD) as compared with other disorders associated with cognitive impairment. The patients were 97 consecutive referrals to an AD clinic. Forty patients had either possible or probable AD, 31 had other dementias (OD) and 26 had mild cognitive impairment (cognitively impaired, not demented; CIND). Patients had blood drawn for serum, red cell folate and B12, as well as other biochemical indicators of nutrition, within 24 h of the Mini-Mental State Examination (MMSE). In the AD group, only B12 was significantly correlated with MMSE. Using regression analysis, B12 contributed significantly to variance in MMSE. There was no correlation between MMSE and serum, red cell folate or B12 in the OD or CIND group and no significant correlation between MMSE and other nutritional indices in any group. These findings suggest the possibility of a specific relationship between B12 levels and severity of cognitive impairment in patients with AD.     

Epidemiologic survey of dementia in a community-dwelling Brazilian population

The authors report the prevalence of dementia in a community-dwelling Brazilian elderly population and correlate prevalence data with educational and socioeconomic levels. The study was conducted in Catanduva, Brazil. A total of 1,656 randomly selected subjects aged 65 years or more were submitted to a health questionnaire, the Mini-Mental State Examination (MMSE), and the Pfeffer Functional Activities Questionnaire (PFAQ). According to the PFAQ and MMSE scores, selected subjects were submitted to clinical, neurologic, and cognitive evaluations. The subjects diagnosed with dementia underwent laboratory tests and brain computed tomography (CT). Dementia was diagnosed in 118 subjects, corresponding to a prevalence of 7.1%. The main clinical diagnoses were Alzheimer disease (AD; 55.1%), vascular dementia (9.3%), and AD with cerebrovascular disease (14.4%). The prevalence increased with age and was higher in women. There was an inverse association with education (3.5% among persons with 8 or more years of schooling to 12.2% among those who were illiterate). Multivariate analysis disclosed significant association between these three variables and dementia. The prevalence of dementia in this Brazilian population was 7.1%, and AD was the most frequent diagnosis. Age, female gender, and low educational level were significantly associated with a higher prevalence of dementia.     

Low plasma vitamin C in Alzheimer patients despite an adequate diet

Objective. To compare the vitamin C and E plasma levels in patients with Alzheimer's disease (AD) and to assess the vitamin C intake and nutritional status. Design. Case-control study. Four groups of sex- and age-matched subjects were compared: severe AD and moderate AD, in patients with moderate AD and controls. Setting. Community and hospitalized patients in the region of Toulouse, France. Participants. Patients with dementia who fulfilled criteria for Alzheimer's disease: severe Alzheimer group (N=20), Mini-Mental State Examination (MMSE) score range 0–9; moderate Alzheimer group (N=24), MMSE 10–23; hospitalized Alzheimer group (N=9), MMSE 10–23. Control group (N=19), MMSE 24–30. Measures. Plasma vitamin E and C were quantified by HPLC-fluorescence. Consumption of raw and cooked fruit and vegetables was evaluated in order to determine the mean vitamin C intakes. Mini Nutritional Assessment (MNA) and plasma albumin were used to measure nutritional status. Results. Institutionalized and community subjects were analysed separately. MNA scores were normal in home-living Alzheimer subjects with moderate dementia and significantly lower in those with severe disease, despite normal plasma albumin levels. In the home-living Alzheimer subjects, vitamin C plasma levels decreased in proportion to the severity of the cognitive impairment despite similar vitamin C intakes, whereas vitamin E remained stable. The hospitalized Alzheimer subjects had lower MNA scores and albumin levels but normal vitamin C intakes, but their plasma vitamin C was lower than that of community-living subjects. Institutionalized Alzheimer subjects had significantly lower MNA scores but normal vitamin C and albumin levels and vitamin C intakes compared with community-dwelling subjects of similar degree of cognitive impairment. Conclusion. Plasma vitamin C is lower in AD in proportion to the degree of cognitive impairment and is not explained by lower vitamin C intake. These results support the hypothesis that oxygen-free radicals may cause damage. Copyright © 1998 John Wiley & Sons, Ltd.     

Role of vitamin B12, folate, and thyroid stimulating hormone in dementia: A hospital-based study in north Indian population

Background:

Vitamin B₁₂ and folate represent modifiable risk factors for dementia. They may increase the risk of Alzheimer′s dementia (AD) and vascular dementia (VaD) as their deficiency can increase the homocysteine level due to slowed methylation reaction. Homocysteine has a neurotoxic effect that could lead to neurologic disturbances. Hence, it is important to explore the status of serum B₁₂ and folate in AD and VaD to evolve the treatment strategies for the same.

Objectives:

A retrospective study was conducted to assess the levels of vitamin B₁₂, folate, and thyroid stimulating hormone (TSH) in serum and the relationship of these factors, including age and sex to cognitive decline in VaD, AD, and dementia due to other causes (DOC).

Materials and Methods:

Serum vitamin B₁₂, folate, TSH, and total cholesterol were studied in 32 AD patients (mean age: 65 years), 12 VaD patients (mean age: 61 years), 83 DOC (mean age: 65 years), and 127 control subjects (mean age: 49 years). Results: In AD, VaD, and DOC, the levels of vitamin B₁₂ and folate were significantly lower (P < 0.002; 0.026; 0.002 for vitamin B₁₂ and P < 0.000 in all the 3 groups for folate) as compared with the controls. Similarly, TSH levels were significantly lower in AD and DOC (P < 0.008; 0.038) as compared with the controls.

Conclusion:

Vitamin B₁₂ and folate were significantly low in both AD and VaD patients. Hence, B vitamin supplementation should be considered as possible targets for the therapeutic intervention in dementia.