Association between vitamin B12 levels and cognitive impairment in older adults

INTRODUCTION

Whether vitamin B₁₂ deficiency is associated with cognitive impairment remains controversial.

OBJECTIVE

To determine the association between vitamin B₁₂ serum levels and cognitive performance.

METHODS

Two-hundred and forty-one adults aged ≥ 60 years who had serum vitamin B₁₂ serum levels measurement were included. Physical and cognitive evaluation was carried out, and three groups were formed: normal cognition (NC), mild cognitive impairment (MCI) and dementia. Vitamin B₁₂ levels were classified as sufficiency (> 400 pg/mL), subclinical deficiency (201-400 pg/mL), and absolute deficiency (≤ 200 pg/mL). Multivariate linear regression analysis was used to evaluate the association between cognitive function and vitamin B₁₂ levels after controlling for confounding variables.

RESULTS

Mean age was 81.4 ± 8.0 years; 68% were females; 17.8 % and 39.8% had absolute and subclinical vitamin B₁₂ deficiency, respectively; 80 individuals (33%) met the criteria for MCI, and 70 (29%), for dementia. Those with MCI and dementia had lower vitamin B₁₂ levels in comparison with those with NC after adjusting for age, gender and educational level (p = 0.019).

CONCLUSIONS

A statistically significant association was observed between global cognitive performance and levels of vitamin B₁₂.

Who judges medical practice?

Lawsuits due to patient perception of inappropriate medical actions are a growing reality in medical practice, which entails widespread concern in the medical community. Lawsuits often entail additional circumstances beyond the primary concern of preventing or sanctioning acts of medical negligence. CETREMI proposes various recommendations aimed at legal and medical professionals to improve this circumstance and avoid harming the doctor-patient relationship.

ASSOCIATION BETWEEN APOE-ε4 CARRIER STATUS AND QUALITATIVE NEUROIMAGING CHARACTERISTICS IN OLDER ADULTS WITH MILD COGNITIVE IMPAIRMENT

BACKGROUND

The pathogenesis of mild cognitive impairment (MCI) is multifactorial and includes the presence of genetic variants such as the ε₄ allele of the apolipoprotein E gene (APOE-ε₄). Association between the APOE-ε₄ carrier status and deleterious structural and functional changes on magnetic resonance imaging (MRI) has been previously described in individuals with Alzheimer's disease. However, the central nervous system changes may possibly develop in earlier stages of cognitive impairment, as reflected in MCI.

OBJECTIVE

The objective of the study was to determine the association between APOE-ε₄ carrier status and qualitative changes on MRI (medial temporal and parietal atrophy), as well as the detection of white matter hyperintensities (WMH) in older adults with MCI, in the memory clinic of a tertiary care hospital in Mexico City.

METHODS

A cross-sectional study of 72 adults aged 60 years or above who underwent an exhaustive clinical, neuroimaging, and neuropsychological evaluation. Multivariate logistic regression models were constructed to determine the association between APOE-ε₄ carrier status and qualitative/quantitative changes on MRI.

RESULTS

Mean age was 75.2 years (± 7.2) and 64% were female. Twenty-one participants were cognitively normal and 51 had MCI. Almost 56% were APOE-ε₄ carriers and were associated with medial-temporal atrophy according to the Scheltens scale (odds ratio [OR]: 20.0, 95% confidence intervals [CI]: 3.03-131.7), parietal atrophy according to the Koedam's score (OR: 6.3; 95% CI 1.03-39.53), and WMH according to the Fazekas scale (OR: 11.7, 95% CI: 1.26-108.2), even after adjusting for age, educational level, and cardiovascular risk factors.

CONCLUSION

The APOE-ε₄ carrier status was associated with medial temporal and parietal atrophy, as well as WMH. Our findings support the hypothesis suggesting the contribution of this genotype to neurodegeneration and cerebral vascular pathology.

Prevalence and incidence of possible vascular dementia among Mexican older adults: Analysis of the Mexican Health and Aging Study

Introduction

Vascular dementia is the second most common cause of dementia. Physical disability and cognitive impairment due to stroke are conditions that considerably affect quality of life. We estimated the prevalence and incidence of possible vascular dementia (PVD) in older adults using data from the Mexican Health and Aging Study (MHAS 2012 and 2015 waves).

Methods

The MHAS is a representative longitudinal cohort study of Mexican adults aged ≥50 years. Data from 14, 893 participants from the 2012 cohort and 14,154 from the 2015 cohort were analyzed to estimate the prevalence and incidence of PVD. Self-respondents with history of stroke were classified as PVD if scores in two or more cognitive domains in the Cross-Cultural Cognitive Examination were ≥ 1.5 standard deviations below the mean on reference norms and if limitations in ≥ 1 instrumental activities of daily living were present. For proxy respondents with history of stroke, we used a score ≥3.4 on the Informant Questionnaire on Cognitive Decline in the Elderly. Crude and standardized rates of prevalent and incident PVD were estimated.

Results

Prevalence of PVD was 0.6% (95% CI, 0.5–0.8) (0.5 with age and sex- standardization). Rates increased with age reaching 2.0% among those aged 80 and older and decreased with educational attainment. After 3.0 years of follow-up, 87 new cases of PVD represented an overall incident rate of 2.2 (95% CI, 1.7–2.6) per 1,000 person-years (2.0 with age and sex- standardization). Incidence also increased with advancing age reaching an overall rate of 9.4 (95% CI, 6.3–13.6) per 1,000 person-years for participants aged >80 years. Hypertension and depressive symptoms were strong predictors of incident PVD.

Conclusion

These data provide new estimates of PVD prevalence and incidence in the Mexican population. We found that PVD incidence increased with age. Males aged 80 years or older showed a greater incidence rate when compared to females, which is comparable to previous estimates from other studies.

Five-Word Test, Screening of Mixed Dementia in Older Adults. Validation Study

INTRODUCTION AND OBJECTIVES

The prevalence of mixed dementia (MixD), defined as the coexistence of Alzheimer's disease (AD) and vascular dementia (VaD), is likely to increase as the population ages. The five-word test (5WT) is a neuropsychological test that differentiates between major and mild neurocognitive disorder (NCD). The objective of the study is to validate 5WT for the detection of MixD.

METHODS

230 participants were evaluated: cognitively healthy (CH) (n=70), mild NCD (n=70), and major NCD (n=90): AD (n=30), VaD (n=30), and MixD (n=30). The Spearman's coefficient, d Sommer and ROC curves were used to determine the construct validity of the 5WT. The linear regression model was performed to determine the association between age and education with 5WT performance.

RESULTS

The mean age was 79 ±7.7 years (P≤.001), 58% were female (P=.252), and the mean education was 9 ±5.3 years (P≤.001). Construct validity when comparing 5WT and MMSE was: Spearman's correlation ρ=.830 (P<.001) and d Sommer=.41 (P<.001). The area under the curve in the total weighted score (TWS) for MixD was .985, with 98% sensitivity (95%CI, 0.96-1.00) and 99% specificity (95%CI, 0.94-1.00), PPV of 88% (95%CI, 0.82-0.89), NPV of 100% (95%CI, 0.96-1.00), and cut-off point ≤16/20 (P<.001).

CONCLUSIONS

5WT is a rapid test with neuropsychological validation for the exploration of cognitive characteristics in major NCD type MixD, regardless of age and education.

Comparison of the Impact of Zika and Dengue Virus Infection, and Other Acute Illnesses of Unidentified Origin on Cognitive Functions in a Prospective Cohort in Chiapas Mexico

Zika has been associated with a variety of severe neurologic manifestations including meningitis and encephalitis. We hypothesized that it may also cause mild to subclinical neurocognitive alterations during acute infection or over the long term. In this observational cohort study, we explored whether Zika cause subclinical or mild neurocognitive alterations, estimate its frequency and duration, and compare it to other acute illnesses in a cohort of people with suspected Zika infection, in the region of Tapachula in Chiapas, Mexico during 2016–2018. We enrolled patients who were at least 12 years old with suspected Zika virus infection and followed them up for 6 months. During each visit participants underwent a complete clinical exam, including a screening test for neurocognitive dysfunction (Montreal Cognitive Assessment score). We enrolled 406 patients [37 with Zika, 73 with dengue and 296 with other acute illnesses of unidentified origin (AIUO)]. We observed a mild and transient impact over cognitive functions in patients with Zika, dengue and with other AIUO. The probability of having an abnormal MoCA score (<26 points) was significantly higher in patients with Zika and AIUO than in those with dengue. Patients with Zika and AIUO had lower memory scores than patients with dengue (Zika vs. Dengue: −0.378, 95% CI−0.678 to −0.078; p = 0.014: Zika vs. AIUO 0.264, 95% CI 0.059, 0.469; p = 0.012). The low memory performance in patients with Zika and AIUO accounts for most of the differences in the overall MoCA score when compared with patients with dengue. Our results show a decrease in cognitive function during acute illness and provides no evidence to support the hypothesis that Zika might cause neurocognitive alterations longer than the period of acute infection or different to other infectious diseases. While effects on memory or perhaps other cognitive functions over the long term are possible, larger studies using more refined tools for neurocognitive functioning assessment are needed to identify these.

Trial Registration: NCT02831699.

Effect of poor glycemic control in cognitive performance in the elderly with type 2 diabetes mellitus: The Mexican Health and Aging Study

Background

Cognitive impairment is twice more frequent in elderly with type 2 diabetes mellitus (DM). This study was conducted to determine the association between glycemic control and cognitive performance among community-dwelling elderly persons in Mexico.

Methods

Cross-sectional study conducted in individuals aged 60 years or elderly participating in the 2012 Mexican Health and Aging Study. Type 2 DM participants were classified in 3 groups according to their glycated hemoglobin levels (Hb_A1c): < 7% (intensive control), 7–7.9% (standard control) or ≥ 8% (poor control), and cognitive performance: low (CCCE ≤44 points), intermediate (44.1–59.52 points), or high (≥59.53 points). Multinomial logistic regression models were constructed to determine this association.

Results

Two hundred sixteen community-dwelling adults aged 60 and older with type 2 diabetes were selected. Subjects in the low cognitive performance group were older (69.7 ± 6.6 vs 65.86 ± 5.18 years, p < .001) and had a lower educational level (2.5 ± 2.6 vs 7.44 ± 4.15 years, p < .000) when compared to the high cognitive performance participants. Hb_A1c ≥ 8% was associated with having low (Odds Ratio (OR) 3.17, 95% CI 1.17–8.60, p = .024), and intermediate (OR 3.23, 95% CI 1.27–8.20, p = .014) cognitive performance; this trend was not found for Hb_A1c 7.0–7.9% group.

The multinomial regression analysis showed that the presence of Hb_A1c ≥ 8% (poor glycemic control) was associated with low (OR 3.17, 95% CI = 1.17–8.60, p = .024), and intermediate (OR 3.23, 95% CI = 1.27–8.20, p = .014) cognitive performance. After adjusting for confounding variables.

Conclusions

Glycemic control with a Hb_A1c ≥ 8% was associated with worse cognitive performance.

ASSOCIATION OF VITAMIN D WITH MILD COGNITIVE IMPAIRMENT AND ALZHEIMER'S DEMENTIA IN OLDER MEXICAN ADULTS

Background

It has been proposed that Vitamin D helps reduce the accumulation of cerebral β-amyloid-42 by innate immune stimulation and phagocytosis activation. An association between low Vitamin D levels and Alzheimer's dementia (AD) has been established. We determined the association between Vitamin D, mild cognitive impairment (MCI), and AD in older Mexican adults (> 65 years).

Methods

Cross-sectional study conducted at the memory clinic in a tertiary-level hospital in Mexico City. We evaluated subjects with MCI, AD, and normal cognition (NC) with available serum Vitamin D [25(OH)D] levels (past 6 months). Three categories were assigned according to 25(OH)D levels: sufficiency (> 30 ng/mL), insufficiency (21-29 ng/mL), and deficiency (≤ 20 ng/mL). Descriptive statistics, means and standard deviations were used. Logistic regression analyses adjusted by age, sex, and educational level were performed.

Results

We evaluated 208 patients. Mean age was 79 ± 1 year, 65% (n = 136) were female; and mean educational level was 6.7 ± 2.3 years. Thirty-one subjects (14%) had NC; 42% (n = 88) had MCI; and 43% (n = 89) had AD. Prevalence of Vitamin D deficiency was 54%, more frequent in the AD group (64%) followed by the MCI (59%) and NC (13%) (p < 0.001) groups. In the multivariate logistic regression analysis, Vitamin D deficiency was associated with MCI (HR 25.02 [confidence interval 95% 4.48-139]; p < 0.001) and AD (HR 41.7 [5.76-301]; p < 0.001) after adjusting for confounders.

Conclusions

Serum Vitamin D deficiency was associated with MCI and dementia; low levels produced a greater effect over executive functions.

Motoric Cognitive Risk Syndrome: Prevalence and Risk of Cognitive Impairment in a Population Studied in the Mexican Health and Aging Study 2012-2015

OBJECTIVES

The aim of this study was to determine the prevalence of Motoric Cognitive Risk (MCR) syndrome, describe associated risk factors and to determine the risk of progression to cognitive impairment after three years of follow-up, in a sample of Mexican older adults.

DESIGN

A prospective panel study of health and aging in Mexico.

SETTING AND PARTICIPANTS

Baseline and follow-up information was obtained from the Mexican Health and Aging Study's 2012 and 2015 waves. A total of 726 subjects aged 60 years or older with normal cognition at baseline were classified into 4 groups: 1) with MCR, 2) with memory complaint only, 3) with slow gait speed only and, 4) without MCR. Cox regression analysis controlling for confounder factors was performed to determine the risk of progression to cognitive impairment in the MCR group.

MEASURES

Data such as gait speed, functional status and cognitive performance (standardized by age and sex in Mexican population) was collected.

RESULTS

MCR prevalence was 14.3%. When compared with non-MCR subjects, the presence of MCR was associated with older age (p<0.01), lower educational status (p=0.05), having two or more comorbidities (p<0.05) and diabetes mellitus diagnosis (p<0.05). At follow-up and after adjusting for confounders, MCR was associated with a 2.4-fold increased risk (95% CI: 1.28-4.26, p=.000) of cognitive impairment.

CONCLUSIONS

MCR syndrome increases the risk of cognitive impairment in Mexican older adults. Simple measurements such as gait evaluation in subjects with memory complaints could allow early identification of those at risk of developing cognitive impairment.

Validation of the Clock Drawing Test Scoring Method in older adults with neurocognitive disorder

Introduction. The Clock Drawing Test (CDT) is a widely used instrument for identifying neurocognitive disorders (NCDs) in older adults. However, there is insufficient evidence to determine the best scoring method, since current quantitative methods involve the assignment of numerical values, while qualitative ones do not allow for objectivity in the diagnosis. Parsey and Schmitter-Edgecombe (2011) proposed a scoring scheme which, in addition to providing a score of the patient’s performance, permits error analysis, thereby making it possible to identify potential underlying cognitive difficulties. Objective. The purpose of this study was to validate the CDT scoring scheme proposed by Parsey and Schmitter-Edgecombe (2011) for screening for NCDs in Mexican older adults. Method. There were 167 participants: 58 cognitively healthy subjects (CH), 52 with mild neurocognitive disorder (mild-NCD), and 57 with major neurocognitive disorder (major-NCD).The CDT scoring method was compared with the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment in Spanish (MoCA-S). Inter- and intra-observer reliability and construct validity were determined and the sensitivity and specificity of this method were calculated. Results. The  age was 75 years (SD ± 8 years) and the  educational attainment was 10.7 years (SD ± 5.2 years). Internal reliability was .750, with an intraclass correlation coefficient of .774. The cut-off point for the CDT in mild-NCD was 14 points (sensitivity: 40%, specificity: 70%) and 12 points for major-NCD (sensitivity: 90%, specificity: 95%).The most frequent errors in the CDT were: graphic, conceptual, spatial, and/or planning difficulties. Discussion and conclusion. This method makes it possibly to quickly and easily explore the cognitive status of the patient. It contains ideal psychometric properties for the detection of patients with major-NCD, in addition to offering the possibility of analyzing performance errors and underlying cognitive difficulties.

Clinical and Demographic Predictors of Conversion to Dementia in Mexican Elderly with Mild Cognitive Impairment

BACKGROUND

Mild cognitive impairment (MCI) is considered a clinical stage between normal cognitive aging and dementia. The clinical course of MCI is heterogeneous, with a significant number of cases progressing to dementia or reverting back to normal.

OBJECTIVE

To determine the predictors of conversion from mild cognitive impairment to dementia among Mexican older adults.

MATERIALS AND METHODS

A sample of 175 persons underwent clinical and neuropsychological evaluation to establish mild cognitive impairment diagnosis. These patients were followed-up for a mean 3.5 years.

RESULTS

Mean age was 81.7 (± 6.9) years, 57% were women, and mean education level was 9.5 (± 6.1) years. Sixty-one percent of mild cognitive impairment participants progressed to dementia. Multivariate Cox regression analysis showed that progression to dementia was associated with age (HR: 4.95; 95% CI: 1.96-12.46; p = 0.001), low education level (HR: 5.81; 95% CI: 1.90-7.78; p < 0.002), history of stroke (HR: 3.92; 95% CI: 1.37-11.16; p < 0.012) and cognitive decline (HR: 1.31; 95% CI: 1.18-1.45; p = 0.000).

CONCLUSIONS

Age, poor education, cognitive decline, and a history of stroke were predictors of conversion to dementia. The identification and control of modifiable risk factors could influence conversion to dementia.

Validity and Reliability of the Spanish Version of the Montreal Cognitive Assessment (MoCA) for the Detection of Cognitive Impairment in Mexico

OBJECTIVE

To establish the validity and reliability of the Montreal Cognitive Assessment in Spanish (MoCA-S) to identify mild cognitive impairment (MCI) and dementia in the Mexican elderly population.

MATERIAL AND METHODS

168 participants from a memory clinic in Mexico City were enrolled and divided into 3 groups: 59 cognitively healthy (CHG), 52 with mild cognitive impairment (MCI) (DSM-5 criteria) and 57 with dementia (NINCDS-ADRDA criteria). The MoCA-S and Mini-Mental State Evaluation (MMSE) were applied at baseline and during the last months to establish intra-observer reliability. ROC curves and a multinomial regression model were constructed to evaluate the effect of age and education on MoCA-S performance.

RESULTS

The mean age of the participants was 76±8.1 years and the education rate was 10.7±5.2. The MoCA-S scores by group were: CHG, 27.3±1.9; MCI, 22.9±2.9; and dementia, 13.7±4.9 (p<0.001). The reliability of the MoCA-S was 0.89 and the intraclass correlation coefficient was 0.955. Sensitivity was 80% and specificity was 75%, with a cut-off point of 26 points for MCI (area under the curve, 0.886; p<0.001). For the dementia group, the sensitivity was 98% and specificity was 93%, with a cut-off point of 24points (area under the curve, 0.998; p<0.001). The multinomial regression showed no association with education and age for both the MCI and dementia groups.

CONCLUSIONS

The MoCA-S is a valid and reliable instrument for MCI and dementia screening in the Mexican population, even after adjusting for age and education.

[Neurological manifestations in critically ill patients]

AIMS

To describe the pathophysiology, diagnosis and clinical manifestations of the neurological complications that critically ill patients often develop in intensive care units, and to discuss their treatment and prognosis, in the light of the most significant contemporary literature.

DEVELOPMENT

The most frequent complication suffered by critically ill patients is sepsis, with encephalopathy as the main manifestation, and this has a direct effect on their prognosis. Polyneuropathy of the critically ill patient is linked to sepsis, as the main precipitating factor, as well as to the presence of high levels of glucose, which plays an important role in deciding whether mechanical ventilation can be withdrawn or not. Myopathy of the critically ill patient is related to the use of fluorinated steroids and neuromuscular blockers, which are frequently administered to these patients. All these entities represent a significant diagnostic challenge for the physician and are accompanied by important sequelae that continue after the patient's discharge from hospital, as well as myopathies and neuropathies associated to the use of drugs that are commonly administered to critically ill patients. It is therefore necessary to be familiar with the pathophysiology of the damage and with the associated factors, if a suitable diagnostic approach is to be employed.

CONCLUSIONS

The incidence of these pathologies and their complications makes them important conditions that require a swift, accurate diagnosis so that treatment can be established early on and a prognosis can also be determined.

[Painful neuropathies: their pathophysiology and treatment]

OBJECTIVES

The purpose of this study is to review the different studies published in the literature concerning the different physiological mechanisms involved in the genesis of painful neuropathy, as well as the diagnostic options and the different pharmacological treatments currently available.

DEVELOPMENT

Distinct pathologies usually condition painful neuropathy, one of the main ones being diabetes mellitus. The triggering phenomenon is often some kind of damage to the tissues that contain nervous pain receptors, which later gives rise to a release of proinflammatory molecules, and triggers a cascade of phenomena that result in disorders in the central and peripheral nervous system (peripheral and central sensitisation). These disorders usually produce clinical manifestations, such as allodynia, paresthesias, among others, and these are sometimes the sole manifestation of painful neuropathy. Diagnosis of this syndrome is at times complicated due to the involvement of thin fibres, which cannot be identified by the conventional methods used in neurophysiological studies. There is also a broad range of pharmaceuticals used in the treatment of painful neuropathy that range from tricyclic antidepressants, non-steroidal anti-inflammatory drugs, opioid analgesics, antiarrhythmics and even agents for topical use.

CONCLUSIONS

Diagnosis of thin fibre neuropathy is usually performed by carrying out a Quantitative Sudomotor Axon Reflex Test, quantitative sensory tests and a skin biopsy. As regards the pharmacological treatment, the new generation of anticonvulsive drugs like gabapentin seems to have advantages over the traditional pharmaceuticals, although their widespread use is still largely restricted by their cost.

[Systemic lupus erythematosus with affection to brainstem: report of three cases]

INTRODUCTION

The frequency with which the central nervous system (CNS) is affected by systemic lupus erythematosus (SLE) varies, according to different series, between 13 and 59%, whereas the brain stem is affected in 5%.

CASE REPORTS

Case 1: a 33 year old male who was submitted to a Nissen funduplicature as a treatment of (hypo)incoercible hiccups. The singultus persisted and some time after a paraplegia appeared. Magnetic resonance (MRI) showed images in the medulla oblongata, and in the cervical and thoracic spine. A biopsy was also performed to examine the cervical lesions and vasculitis was diagnosed. The patient began treatment with prednisone (1 mg/kg) and two months after symptoms had begun to improve he presented an episode of bilateral optic neuritis. Until this last event, the immunological studies had been positive. Case 2: female aged 19 who had had SLE for eight months. The illness began suddenly with bilateral paralysis of the sixth cranial nerve, vertical and horizontal nystagmus, dysdiadochokinesia, truncal ataxia, 4/5 muscular strength in the upper limbs and 3/5 in the lower limbs, and left flexor plantar response, but indifferent on the right hand side. MR showed T2 hyperintensities in the pons, medulla oblongata and the junction of medulla and upper spinal cord. Case 3: female aged 31 with sudden onset of the illness, characterised by diplopy and presence of internuclear ophthalmoplegia. Brain MR showed images of T1 hypointense and T2 hyperintense in the pontobulbar region.

CONCLUSION

A brain stem disorder in patients suffering from SLE is one of the rarest manifestations of this pathological condition of the CNS and is probably caused by vasculitis