Serum 25-hydroxyvitamin D concentration and cognitive impairment

Magnetic resonance spectroscopy in the hippocampus of adult APP/PS1 mice following chronic vitamin D deficiency

Vitamin D (VitD) deficiency can exacerbate AD progression and may cause changes in brain metabolite levels that can be detected by magnetic resonance spectroscopy (MRS). The purpose of this study was to determine whether chronic VitD deficiency in an AD mouse model caused persistent metabolite levels changes in the hippocampus associated with memory performance. Six-month-old APPSwe/PS1ΔE9 (APP/PS1) mice (N = 14 mice/group) were fed either a VitD deficient (VitD-) diet or a control diet. Metabolite level changes in the hippocampus were evaluated by 1H MRS using a 9.4 T MRI. Ventricle volume was assessed by imaging and spatial memory was evaluated using the Barnes maze. All measurements were made at 6, 9, 12, and 15 months of age. At 15 months of age, amyloid plaque load and astrocyte number were evaluated histologically (N = 4 mice/group). Levels of N-acetyl aspartate and creatine were lower in VitD- mice compared to control diet mice at 12 months of age. VitD deficiency did not change ventricle volume. Lactate levels increased over time in VitD- mice and increases from 12 to 15 months were negatively correlated with changes in primary latency to the target hole in the Barns Maze. VitD- mice showed improved spatial memory performance compared to control diet mice. VitD- mice also had more astrocytes in the cortex and hippocampus at 15 months than control diet mice. This study suggests that severe VitD deficiency in APP/PS1 mice may lead to compensatory changes in metabolite and astrocyte levels that contribute to improved performance on spatial memory tasks.

Chronic Kidney Disease Induces Cognitive Impairment in the Early Stage

OBJECTIVE

Previous research indicates a link between cognitive impairment and chronic kidney disease (CKD), but the underlying factors are not fully understood. This study aimed to investigate the progression of CKD-induced cognitive impairment and the involvement of cognition-related proteins by developing early- and late-stage CKD models in Sprague-Dawley rats.

METHODS

The Morris water maze test and the step-down passive avoidance task were performed to evaluate the cognitive abilities of the rats at 24 weeks after surgery. Histopathologic examinations were conducted to examine renal and hippocampal damage. Real-time PCR, Western blotting analysis, and immunohistochemical staining were carried out to determine the hippocampal expression of brain-derived neurotrophic factor (BDNF), choline acetyltransferase (ChAT), and synaptophysin (SYP).

RESULTS

Compared with the control rats, the rats with early-stage CKD exhibited mild renal damage, while those with late-stage CKD showed significantly increased serum creatinine levels as well as apparent renal and brain damage. The rats with early-stage CKD also demonstrated significantly impaired learning abilities and memory compared with the control rats, with further deterioration observed in the rats with late-stage CKD. Additionally, we observed a significant downregulation of cognition-related proteins in the hippocampus of rats with early-stage CKD, which was further exacerbated with declining renal function as well as worsening brain and renal damage in rats with late-stage CKD.

CONCLUSION

These results suggest the importance of early screening to identify CKD-induced cognitive dysfunction promptly. In addition, the downregulation of cognition-related proteins may play a role in the progression of cognitive dysfunction.

Vitamin D status and cognitive performance in community-dwelling adults: A dose-response meta-analysis of observational studies

Low vitamin D status is linked with poorer cognition in adults while findings in relation to high levels are mixed.We performed a systematic review and meta-analyses to examine dose-response associations between 25-hydroxyvitamin D (25OHD) levelsand cognitive performance in community-dwelling adults. Thirty-eight observational studies were included in dose-response meta-analyses. Positive, nonlinear associations were identified between baseline25OHD levels and global cognition incross-sectional and longitudinal analyses, and for performance in memory and executive function in longitudinal analyses. When restricted to studies involving older adults, thepattern emerged forspecific domains in cross-sectional analyses. Poorer performance was associated with low 25OHD levels, while a sharp improvement was associated withlevels up to 60-70 nM/L. Further improvement was observed only for longitudinal global cognition. Our findings support the association between low vitamin D and poorer cognition and suggest levels of at least 60 nM/L are associated with better cognition during ageing.

Low vitamin D status is associated with inflammatory response in older patients with cerebral small vessel disease

OBJECTIVES

This study aimed to determine the association of the NF-κB inflammatory signaling pathway with vitamin D status in older cerebral small vessel disease (SVD) patients.

METHODS

We measured serum 25(OH)D, pro-and anti-inflammatory cytokines, and mRNA levels of the vitamin D-activating enzyme, CYP27B1, as well as NF-kB, COX-2, the chemokine-CCL2, IL-1β, IL-6, TNF-α, TGF-β, and IL-10, in cerebral SVD patients aged ≥60 years presenting with vascular dementia and age and gender-matched healthy controls.

RESULTS

Low vitamin D status (insufficiency: serum 25(OH)D 12-20 ng/ml; deficiency: ≤12 ng/ml) was more prevalent among patients compared to controls. The mRNA levels of NF-kB, COX-2, CCL2, IL-1β, and IL-6, and serum levels of pro-inflammatory cytokines (IL-1α, IL-1β, IL-6, and TNF-α) were significantly higher in cases compared to controls. There was a significant correlation between CYP27B1 and NF-kB, COX-2, CCL2, and IL-1β gene expression. Serum IL-1α, IL-1β, and IL-6 concentrations and the expression of CCL-2, NF-kB2, and NF-kB3 genes were higher in vitamin D-deficient subjects compared to vitamin D-sufficient subjects. There was a significant negative correlation between serum 25(OH)D and IL-1α, IL-6, and TNF-α, and a positive correlation between 25(OH)D and IL-10.

CONCLUSION

Low vitamin D is associated with an inflammatory response via NF-kB signaling, which could play a role in the etio-pathogenesis of SVD. Further large-scale studies are required to validate our findings.

Neuroprotective effects of combined therapy with memantine, donepezil, and vitamin D in ovariectomized female mice subjected to dementia model

Women older than 60 have a higher risk of dementia, aging-related cognitive decline, and Alzheimer's Disease (AD) than the rest of the population. The main reason is hormonal senescence after menopause, a period characterized by a decline in estrogen levels. Since the effectiveness of drugs currently approved for the treatment of AD is limited, it is necessary to seek the development of new therapeutic strategies. Vitamin D deficiency is prevalent in AD patients and individuals with dementia in general. The supplementation of this vitamin in dementia patients might be an interesting approach for increasing the effectiveness of pre-existing medications for dementia treatment. Thus, the present study aims to investigate the effect of vitamin D treatment associated with memantine and donepezil in female mice submitted to ovariectomy (OVX) for five months and subjected to a dementia animal model induced by intracerebroventricular injection of aggregated amyloid βeta (Aβ_1-42). For this purpose, Balb/c mice were divided into five experimental groups, which received 17 days of combined therapy with vitamin D, donepezil, and memantine. Then, animals were subjected to behavioral tests. OVX groups exhibited reduced levels of estradiol (E2) in serum, which was not altered by the combined therapy. Higher levels of vitamin D3 were found in the OVX animals submitted to the triple-association treatment. Mice exposed to both OVX and the dementia animal model presented impairment in short and long-term spatial and habituation memories. Also, female mice exposed to Aβ and OVX exhibited a reduction in brain-derived neurotrophic factor (BDNF) and interleukin-4 (IL-4) levels, and an increase in tumor necrose factor-α (TNFα) levels in the hippocampus. Besides, increased levels of IL-1β in the hippocampus and cerebral cortex were observed, as well as a significant increase in immunoreactivity for glial fibrillary acidic protein (GFAP), an astrocytes marker, in the hippocampus. Notably, triple-association treatment reversed the effects of the exposition of mice to Aβ and OVX in the long-term spatial and habituation memories impairment, as well as reversed changes in TNFα, IL-1β, IL-4, and GFAP immunoreactivity levels in the hippocampus of treated animals. Our results indicate that the therapeutic association of vitamin D, memantine, and donepezil has beneficial effects on memory performance and attenuated the neuroinflammatory response in female mice subjected to OVX associated with a dementia animal model.

Vitamin D3 improves spatial memory and modulates cytokine levels in aged rats

Vitamin D3 deficiency is associated with an increased risk of dementia. An association between vitamin D3 deficiency and subjective cognitive complaints in geriatric patients has been previously reported. This study aimed to evaluate the effects of two doses of vitamin D3 on spatial memory (using the Radial Maze) and cytokine levels [tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10)] on 2-, 6-, 13-, 22-, and 31-month-old male Wistar rats. Animals were supplemented with vitamin D3 at doses of 42 IU/kg and 420 IU/kg for 21 days. A radial maze test was performed to evaluate spatial memory. After the behavioral test, the frontal cortex and hippocampus were dissected for enzyme immunoassay analyses to measure the cytokine levels (TNFα, IL-1β, IL-6, and IL-10). Our results showed that vitamin D3 supplementation reversed spatial memory impairment at the supplemented doses (42 and 420 IU/kg) in 6-, 13-, and 22-month-old animals and at a dose of 420 IU/kg in 31-month-old animals. The lower dose (42 IU/kg) regulates both pro- and anti-inflammatory cytokines mainly in the frontal cortex. Our results suggest that vitamin D3 has a modulatory action on pro- and anti-inflammatory cytokines, since older animals showed increased cytokine levels compared to 2-month-old animals, and that vitamin D3 may exert an immunomodulatory effect on aging.

Role of Vitamin D Deficiency in the Pathogenesis of Cardiovascular and Cerebrovascular Diseases

Deficiency in vitamin D (VitD), a lipid-soluble vitamin and steroid hormone, affects approximately 24% to 40% of the population of the Western world. In addition to its well-documented effects on the musculoskeletal system, VitD also contributes importantly to the promotion and preservation of cardiovascular health via modulating the immune and inflammatory functions and regulating cell proliferation and migration, endothelial function, renin expression, and extracellular matrix homeostasis. This brief overview focuses on the cardiovascular and cerebrovascular effects of VitD and the cellular, molecular, and functional changes that occur in the circulatory system in VitD deficiency (VDD). It explores the links among VDD and adverse vascular remodeling, endothelial dysfunction, vascular inflammation, and increased risk for cardiovascular and cerebrovascular diseases. Improved understanding of the complex role of VDD in the pathogenesis of atherosclerotic cardiovascular diseases, stroke, and vascular cognitive impairment is crucial for all cardiologists, dietitians, and geriatricians, as VDD presents an easy target for intervention.

Vitamin D, a Secosteroid Hormone and Its Multifunctional Receptor, Vitamin D Receptor, in Alzheimer's Type Neurodegeneration

Vitamin D is a secosteroid hormone exerting neurosteroid-like properties. Its well-known nuclear hormone receptor, and recently proposed as a mitochondrial transcription factor, vitamin D receptor, acts for its primary functions. The second receptor is an endoplasmic reticulum protein, protein disulfide isomerase A3 (PDIA3), suggested to act as a rapid response. Vitamin D has effects on various systems, particularly through calcium metabolism. Among them, the nervous system has an important place in the context of our subject. Recent studies have shown that vitamin D and its receptors have numerous effects on the nervous system. Neurodegeneration is a long-term process. Throughout a human life span, so is vitamin D deficiency. Our previous studies and others have suggested that the out-come of long-term vitamin D deficiency (hypovitaminosis D or inefficient utilization of vitamin D), may lead neurons to be vulnerable to aging and neurodegeneration. We suggest that keeping vitamin D levels at adequate levels at all stages of life, considering new approaches such as agonists that can activate vitamin D receptors, and utilizing other derivatives produced in the synthesis process with UVB are crucial when considering vitamin D-based intervention studies. Given most aspects of vitamin D, this review outlines how vitamin D and its receptors work and are involved in neurodegeneration, emphasizing Alzheimer's disease.

Association between lower serum vitamin D (25-hydroxy-cholecalciferol) concentrations and cognitive impairment in older adults: data from a populational-based cohort study in a middle-income country

OBJECTIVE

To investigate the association between serum vitamin D (25-hydroxy-cholecalciferol) (25(OH)D) concentrations and cognitive impairment in older adults living in Southern Brazil.

DESIGN

Cross-sectional analysis using data from the second follow-up wave of the populational-based EpiFloripa Aging Cohort Study was collected in 2013-2014.

SETTING

Cognitive impairment was evaluated using the Mini-Mental State Examination (MMSE). Blood samples were collected to measure serum vitamin D concentrations using a chemiluminescent microparticle immunoassay. Vitamin D concentrations were distributed in quartiles (Q1: 4·0-20·7 ng/ml; Q2: 20·8-26·6 ng/ml; Q3: 26·7-32·0 ng/ml and Q4: 32·1-60·1 ng/ml), and its association with cognitive impairment was tested by crude and adjusted logistic regression (sociodemographic, behavioural and health aspects) using Q4 as a reference group.

PARTICIPANTS

200 men and 371 women aged 60 years or older participated in this study.

RESULTS

The prevalence of probable cognitive impairment was 21·7 %. Those without cognitive impairment had a higher mean of vitamin D serum concentrations (26·8 v. 24·6, P = 0·014). In the crude analysis, only individuals in Q2 of vitamin D presented an increased risk for probable cognitive impairment compared with Q4 (highest quartile) (OR 2·65, 95 % CI 1·46, 4·81), remaining significant in the adjusted analysis (OR 6·04, 95 % CI 2·78, 13·13). While Q1 (lowest quartile) was not associated in the crude analysis, but when adjusted, an increased risk of cognitive impairment was observed.

CONCLUSION

The lowest quartile of vitamin D was directly associated with probable cognitive impairment in older adults in Southern Brazil. More studies are needed to investigate whether maintaining adequate serum levels may represent a significant factor in preventing age-related neurological disorders as well as to verify the need for new cutoff points for this age group.

Nuclear hormone receptors in demyelinating diseases

Demyelination results from the pathological loss of myelin and is a hallmark of many neurodegenerative diseases. Despite the prevalence of demyelinating diseases, there are no disease modifying therapies that prevent the loss of myelin or promote remyelination. This review aims to summarize studies in the field that highlight the importance of nuclear hormone receptors in the promotion and maintenance of myelination and the relevance of nuclear hormone receptors as potential therapeutic targets for demyelinating diseases. These nuclear hormone receptors include the estrogen receptor, progesterone receptor, androgen receptor, vitamin D receptor, thyroid hormone receptor, peroxisome proliferator-activated receptor, liver X receptor, and retinoid X receptor. Pre-clinical studies in well-established animal models of demyelination have shown a prominent role of these nuclear hormone receptors in myelination through their promotion of oligodendrocyte maturation and development. The activation of the nuclear hormone receptors by their ligands also promotes the synthesis of myelin proteins and lipids in mouse models of demyelination. There are limited clinical studies that focus on how the activation of these nuclear hormone receptors could alleviate demyelination in patients with diseases such as multiple sclerosis (MS). However, the completed clinical trials have reported improved clinical outcome in MS patients treated with the ligands of some of these nuclear hormone receptors. Together, the positive results from both clinical and pre-clinical studies point to nuclear hormone receptors as promising therapeutic targets to counter demyelination.

Role of Neural Stem Cells and Vitamin D Receptor (VDR)-Mediated Cellular Signaling in the Mitigation of Neurological Diseases

Specific stem cell-based therapies for treating Alzheimer's disease, Parkinson's disease, and schizophrenia are gaining importance in recent years. Accumulating data is providing further support by demonstrating the efficacy of neural stem cells in enhancing the neurogenesis in the aging brain. In addition to stem cells, recent studies have shown the efficacy of supplementing vitamin D in promoting neurogenesis and neuronal survival. Studies have also demonstrated the presence of mutational variants and single-nucleotide polymorphisms of the vitamin D receptor (VDR) in neurological disorders; however, implications of these mutations in the pathophysiology and response to drug treatment are yet to be explored. Hence, in this article, we have reviewed recent reports pertaining to the role of neural stem cells and VDR-mediated cellular signaling cascades that are involved in enhancing the neurogenesis through Wnt/β-catenin and Sonic Hedgehog pathways. This review benefits neurobiologists and pharmaceutical industry experts to develop stem cell-based and vitamin D-based therapies to better treat the patients suffering from neurological diseases.

Investigating Potential Dose-Response Relationships between Vitamin D Status and Cognitive Performance: A Cross-Sectional Analysis in Middle- to Older-Aged Adults in the Busselton Healthy Ageing Study

Low vitamin D status has been linked to adverse cognitive outcomes in older adults. However, relationships at higher levels remain uncertain. We aimed to clarify patterns of association between vitamin D status and cognitive performance, using flexible regression methods, in 4872 middle- to older-aged adults (2678 females) from the Busselton Healthy Ageing Study. Cross-sectional associations of serum levels of 25-hydroxyvitamin D (25OHD) and performance in cognitive domains were modelled using linear regression and restricted cubic splines, controlling for demographic, lifestyle, and health factors. Mean ± SD serum 25OHD levels were 78 ± 24 nM/L for women and 85 ± 25 nM/L for men. Increasing levels in women were associated with better global cognition (linear trend, p = 0.023) and attention accuracy (continuity of attention), with improvement in the latter plateauing around levels of 80 nM/L (nonlinear trend, p = 0.035). In men, increasing levels of serum 25OHD were associated with better attention accuracy (linear trend, p = 0.022), but poorer semantic verbal fluency (linear trend, p = 0.025) and global cognition (nonlinear trend, p = 0.015). We identified patterns of association between serum 25OHD levels and cognitive performance that may reflect early dose–response relationships, particularly in women. Longitudinal analyses extending through to older ages may help to clarify the nature, strength, and temporality of these relationships.

High-dose Vitamin D Supplementation and Improvement in Cognitive Abilities, Insomnia, and Daytime Sleepiness in Adolescent Girls

Introduction:

Vitamin D may affect the modulation of signaling pathways in the central nervous system. We aimed to evaluate the effect of high-dose vitamin D supplementation on neuropsychological functions in female adolescents.

Methods:

We studied the effects of 9 weeks of vitamin D supplementation (50000 IU vitamin D3 [cholecalciferol]/week) on cognitive abilities and sleep disorders in 940 adolescent girls.

Results:

Oral vitamin D supplementation improved cognitive abilities, including memory, inhibitory control, selective attention, decision making, planning, sustained attention, and cognitive flexibility in healthy adolescent girls (P<0.001). The prevalence of subjects with insomnia after intervention fell from 15.0% to 11.3%. Similar results were also found for the prevalence of sleepiness (15.6% reduced to 14.7%), or cases with both insomnia and sleepiness (8.0% reduced to 6.1%; P<0.05).

Conclusion:

High dose of vitamin D can improve cognitive abilities and alleviate insomnia and daytime sleepiness in adolescent girls. Further investigations are required on different population groups (age and gender) to determine the sustainability of these effects. The value of vitamin D therapy in other neurological disorders would also be of research interest.

Exploring the Effects of Vitamin D Supplementation on Cognitive Functions and Mental Health Status in Subjects Under Methadone Maintenance Treatment

OBJECTIVES

Vitamin D deficiency may be linked to several mental complications including cognitive deficits, depression, and anxiety in patients under methadone maintenance treatment (MMT). This study was designed to explore the effect of vitamin D supplementation on cognitive functions and mental health parameters in subjects under MMT.

METHODS

This randomized, double-blinded, placebo-controlled clinical trial was carried out among 64 patients under MMT. Participants were randomly allocated to receive either 50,000 IU vitamin D supplements (n = 32) or placebo (n = 32) every 2 weeks for 24 weeks. Cognitive functions and mental health parameters were taken at baseline and posttreatment to evaluate relevant variables.

RESULTS

After the 24-week intervention, compared with the placebo, serum 25(OH) vitamin D levels significantly increased in participants who received vitamin D supplements (β 14.50; 95% confidence interval [CI], 13.17-15.83; P < 0.001). In addition, compared with the placebo, subjects who received vitamin D had a significant reduction in Iowa Gambling Task (β -6.25; 95% CI, -8.60 to -3.90; P < 0.001), and significant increases in Verbal Fluency Test (β 2.82; 95% CI, 0.78-4.86; P = 0.007), Immediate Logic Memory (β 1. 32; 95% CI, 0.27-2.37; P = 0.01), Reverse Digit Span (β 2.06; 95% CI, 1.18-2.94; P < 0.001) and visual working memory (β 0.75; 95% CI, 0.33-1.16; P = 0.001). Also, vitamin D supplementation significantly improved BDI (β -2.76; 95% CI, -3.97 to -1.55; P < 0.001) compared with the placebo. When we applied Bonferroni correction, LM-Immediate (P = 0.07) became nonsignificant, and other mental health parameters did not alter.

CONCLUSIONS

Overall, taking 50,000 IU vitamin D supplements every 2 weeks for 24 weeks by patients under MMT had beneficial effects on cognitive functions and some mental health parameters. Further studies are needed to confirm our findings.

Serum Vitamin D and Depressive Symptomatology among Boston-Area Puerto Ricans

BACKGROUND

Low vitamin D status, assessed using serum 25-hydroxyvitamin D [25(OH)D] concentration, has been associated with depression, but research among minority populations, such as Puerto Ricans is limited. We examined the association between serum 25(OH)D and self-reported depressive symptomatology across 3 waves of follow-up in a cohort of Puerto Rican adults residing in Massachusetts.

OBJECTIVES

We evaluated the cross-sectional and longitudinal associations between serum 25(OH)D and self-reported depressive symptoms in the Boston Puerto Rican Health Study (BPRHS) cohort.

METHODS

Participants of the BPRHS were evaluated for depressive symptoms using the Center for Epidemiologic Studies Depression Scale (CES-D). Serum 25(OH)D was measured at baseline (n = 1434), year 2 (n = 1218), and year 5 (n = 914). We categorized serum 25(OH)D concentration as sufficient (≥20 ng/mL), insufficient (12 to <20 ng/mL), and deficient (<12 ng/mL). Multivariable linear regression was used for cross-sectional analyses at baseline, and repeated measures mixed effects modeling was used over 3 waves of follow-up for longitudinal analyses. We conducted sensitivity analyses in vitamin D supplement nonusers and participants with complete data on baseline serum 25(OH)D and CES-D at all 3 visits.

RESULTS

Serum 25(OH)D concentration was not associated with CES-D score in cross-sectional analysis [β = -0.85; 95% CI: -2.80, 1.10 for deficient compared with sufficient 25(OH)D; P-trend = 0.59] or in longitudinal analyses over 5 y [β = -0.41; 95% CI: -1.95, 1.13 for deficient compared with sufficient 25(OH)D; P-trend = 0.93]. Results were similar in sensitivity analyses restricted to vitamin D supplement nonusers (n = 1371) and in analyses conducted in participants with complete measures of baseline serum 25(OH)D and CES-D score at all 3 visits (n = 887) [β = -0.12; 95% CI: -1.98, 1.74 for deficient compared with sufficient 25(OH)D; P-trend = 0.93].

CONCLUSIONS

We did not observe a significant association between serum 25(OH)D and depressive symptomatology in the BPRHS cohort.

Proposed Neuroimmune Roles of Dimethyl Fumarate, Bupropion, S-Adenosylmethionine, and Vitamin D3 in Affording a Chronically Ill Patient Sustained Relief from Inflammation and Major Depression

We had discussed earlier that, after most of the primary author's multiple sclerosis (MS) symptoms were lessened by prior neuroimmune therapies, use of dimethyl fumarate (DMF) gradually subdued his asthma and urticaria symptoms, as well as his MS-related intercostal cramping; and bupropion supplemented with S-adenosylmethionine (SAMe) and vitamin D3 (vit-D3) helped remit major depression (MD). Furthermore, the same cocktail (bupropion plus supplements), along with previously discussed routines (yoga, meditation, physical exercises, and timely use of medications for other illnesses), continued to subdue MD during new difficulties with craniopharyngioma, which caused bitemporal vision loss; sphenoid sinus infections, which caused cranial nerve-VI (CN6) palsy and diplopia; and through their treatments. Impressed by the benefit the four compounds provided, in this manuscript, we focus on explaining current neuroimmune literature proposals on how: (1) DMF impedes inflammation, oxidative stress, and cell death in CNS and peripheral tissues; (2) Bupropion curbs anxiety, MD, and enhances alertness, libido, and moods; (3) SAMe silences oxidative stress and depression by multiple mechanisms; and (4) Vit-D3 helps brain development and functioning and subdues inflammation. we realize that herein we have reviewed proposed mechanisms of remedies we discovered by literature searches and physician assisted auto-experimentation; and our methods might not work with other patients. We present our experiences so readers are heartened to reflect upon their own observations in peer-reviewed forums and make available a wide body of information for the chronically ill and their physicians to benefit from.

Association between chronic kidney disease and Alzheimer's disease: an update

It has been accepted that kidney function is connected with brain activity. In clinical studies, chronic kidney disease (CKD) patients have been found to be prone to suffering cognitive decline and Alzheimer's disease (AD). The cognitive function of CKD patients may improve after kidney transplantation. All these indicators show a possible link between kidney function and dementia. However, little is known about the mechanism behind the relation of CKD and AD. This review discusses the associations between CKD and AD from the perspective of the pathophysiology of the kidney and complications and/or concomitants of CKD that may lead to cognitive decline in the progression of CKD and AD. Potential preventive and therapeutic strategies for AD are also presented. Further studies are warranted in order to confirm whether the setting of CKD is a possible new determinant for cognitive impairment in AD.

Serum vitamin D level is associated with speed of processing in multiple sclerosis patients

Multiple Sclerosis (MS) is often associated with low serum 25(OH)D levels, as well as cognitive dysfunctions. The relationship between 25(OH)D and the most commonly affected cognitive domain in MS; processing speed, is poorly explored. The purpose of this study is to: (1) assess the effect of serum 25(OH)D change on processing speed in MS, and (2) explore the relationship between serum 25(OH)D and brain volume changes in MS. A retrospective chart review was conducted, data from 299 patients were extracted (baseline), of whom 163 had follow-up measurements (after at least a 9-month interval). The Symbol Digits Modalities Test (SDMT) was used as a measure of processing speed. MRI data was available from 78 individuals at baseline, and 70 at follow-up. SDMT scores and brain volumes (Cerebellum (total, grey, and white), intracranial, Grey Matter (GM), and White Matter (WM)) were compared based on 25(OH)D levels and their changes towards follow-up. Results indicated that patients with deficient 25(OH)D levels had lower SDMT scores when compared to those with sufficient levels, and SDMT scores improved as a function of 25(OH)D. For MRI measures, only patients with sufficient 25(OH)D levels during both assessment periods had significant changes in intracranial and total cerebellum volumes. We conclude that 25(OH)D levels seem to have an effect on processing speed in MS, thus the importance of clinical monitoring and supplementation in this regard is reinforced.

A Review of the Relationship Between Vitamin D and Parkinson Disease Symptoms

Vitamin D is a fat-soluble secosteroid that exerts its effects by binding to the vitamin D receptor (VDR), through which it directly and indirectly modulates the expression of hundreds to thousands of genes. While originally known for its role in regulating calcium homeostasis and metabolism, vitamin D is now associated with many other health conditions, including Parkinson's disease (PD). A high prevalence of vitamin D deficiency has been noted in PD for at least the past two decades. These findings, along with the discovery that the VDR and 1α-hydroxylase, the enzyme that converts vitamin D to its active form, are highly expressed in the substantia nigra, led to the hypothesis that inadequate levels of circulating vitamin D may lead to dysfunction or cell death within the substantia nigra. Studies investigating the relationship between vitamin D status and PD, however, have been inconsistent. Two prospective studies examined the association between mid-life vitamin D levels and risk of PD and produced conflicting results-one demonstrated an increased risk for PD with lower mid-life vitamin D levels, and the other showed no association between vitamin D and PD risk. One of the most consistent findings in the literature is the inverse association between serum vitamin D level and motor symptom severity in cross-sectional studies. While these data suggest that vitamin D may modify the disease, another likely explanation is confounding due to limited mobility. Fall risk has been associated with vitamin D in PD, but more study is needed to determine if supplementation decreases falls, which has been demonstrated in the general population. The association between vitamin D and non-motor symptoms is less clear. There is some evidence that vitamin D is associated with verbal fluency and verbal memory in PD. Studies in PD have also shown associations between vitamin D status and mood, orthostatic hypotension and olfactory impairment in PD. While more research is needed, given the numerous potential benefits and limited risks, vitamin D level assessment in PD patients and supplementation for those with deficiency and insufficiency seems justified.

The effect of vitamin D on cognitive functions in young female patients: a prospective controlled study using the Montreal Cognitive Assessment

AIM

Our aim was to determine whether there is a relationship between vitamin D [25(OH)D] and cognitive functioning in women with low 25(OH)D levels.

METHODS

Ninety female patients, 25-45 years of age, who attended our outpatient clinic and had 25(OH)D levels < 30 ng/mL, were included. The Montreal Cognitive Assessment (MoCA) scale was used to determine cognitive functioning; the scale is divided into seven subgroups. Patients were divided into three subgroups according to their 25(OH)D levels. After a three-month period of 25(OH) D replacement, the patients underwent a re-evaluation using the MoCA scale.

RESULTS

The total MoCA score before treatment was significantly different from the score after treatment (p < 0.05). Language and delayed recall functions were significantly different before and after treatment (p < 0.05).

CONCLUSION

Vitamin D levels were related to cognitive functioning in our study group.

Association of vitamin D nutrition with neuro-developmental outcome of infants of slums in Bangladesh

The association of vitamin D with neuro-behavioral outcomes of young children is unclear, particularly of those who reside in tropical countries and are otherwise exposed to adequate sun light. To investigate this association, we analysed the existing data of poor infants, who participated in an observational, prospective-cohort (MalED) study, conducted in a slum of Dhaka-city. We assessed 265 infants aged 6–8 months for cognitive, motor, language and behavior development using Bayley-III. Information about infants’ temperament and communicative skills were provided by the mothers through a culturally modified “temperament-scale” and a “communicative-developmental inventory”. Serum concentration of vitamin D [25(OH)D] was measured in 205 infants. Around 28.3% of infants in this community had low level vitamin D, with the cut-off at <50 nmol/L. After controlling for all possible covariates, a multivariable-adjusted linear regression showed that children with vitamin D levels <50 nmol/L had significantly lower scores in two dimensions of temperament: activity (B±SE 1.64±0.78; 95%CI 0.10, 3.18; p = 0.037; effect size 0.37 SDs) and soothabilty (2.02±0.70; 0.64, 3.41; p = 0.004; 0.53 SDs), compared to children with vitamin D levels of ≥50nmol/L. These infants also scored low in word comprehensions (1.28±0.62; 0.05, 2.51; p = 0.042; 0.23 SDs) and were less active during test-procedures (0.33±0.16; 0.02, 0.64; p = 0.035; 0.27 SDs). Both the groups tested similarly in cognitive and motor scores. This study found, despite adequate sunlight-exposure, one in four infants of this slum-community are suffering from a subclinical vitamin D deficiency. Higher levels of vitamin D in these infants showed a positive association with temperament, language and behavior but not with cognitive and motor development. Our findings highlight the early-detected extra-skeletal neuro-behavioral role of vitamin D. Future studies in this area will give more insight.

A systematic review of existing peripheral biomarkers of cognitive aging: Is there enough evidence for biomarker proxies in behavioral modification interventions?: An initiative in association with the nutrition, exercise and lifestyle team of the Canadian Consortium on Neurodegeneration in Aging

Peripheral biomarkers have shown significant value in predicting brain health and may serve as a useful proxy measurement in the assessment of evidence-based lifestyle behavior modification programs, including physical activity and nutrition programs, that aim to maintain cognitive function in late life. The aim of this systematic review was to elucidate which peripheral biomarkers are robustly associated with cognitive function among relatively healthy non-demented older adults. Following the standards for systematic reviews (PICO, PRIMSA), and employing MEDLINE and Scopus search engines, 222 articles were included in the review. Based on the review of biomarker proxies of cognitive health, it is recommended that a comprehensive biomarker panel, or biomarker signature, be developed as a clinical end point for behavior modification trials aimed at enhancing cognitive function in late life. The biomarker signature should take a multisystemic approach, including lipid, immune/inflammatory, and metabolic biomarkers in the biological signature index of cognitive health.

Molecular basis of vitamin D action in neurodegeneration: the story of a team perspective

Vitamin D, a secosteroid hormone, has, over the years, mainly been known for its classic role in the maintenance of calcium homeostasis of the human body. However, there is increasing understanding that vitamin D contributes to the regulation of Ca²⁺ homeostasis, especially via voltage-gated calcium channels, in another major organ that uses calcium, the brain. Almost 30 years ago, the role of dysregulation in the aging brain and in Alzheimer's disease (AD) gave rise to the Ca²⁺ hypothesis of brain aging and dementia. We thus made calcium homeostasis the starting point of our studies, proposing the notion that the consequences of long-term deficiency and/or inefficient utilization of vitamin D may cause the disruption of calcium homeostasis in neurons, this creating a vulnerability of neurons to aging and neurodegeneration. In this mini-review, we aim to describe the potential of vitamin D (cholecalciferol) as a neurosteroid based on our findings and conclusions.

Vitamin D basis of Alzheimer's disease: from genetics to biomarkers

Alzheimer's disease (AD) is a progressive neurodegenerative disorder seen mostly in the elderly population. While to date AD research has focused on either neurochemical disruptions, genetic studies, or the pathological hallmarks, little has been done to establish a novel approach that would encompass all three aspects, one that would overcome the current barriers in AD research and determine the cause of AD and, eventually, discover a treatment. Meanwhile, there have been strong indications in recent years that vitamin D, a secosteroid hormone, and its receptors are fundamentally involved in neurodegenerative mechanisms. Observational studies have pointed to vitamin D deficiency as a genetic risk factor for AD, Parkinson's disease (PD), vascular dementia, and multiple sclerosis (MS), as well as other neurological disorders, brought about by alterations in genes involved in metabolism, transportation, and actions of vitamin D. Molecular studies have demonstrated that vitamin D treatments prevent amyloid production while also increasing its clearance from the brain in AD. Finally, recent vitamin D intervention studies have reported significant improvement in cognitive performance in subjects with senile dementia, mild cognitive impairment, and AD. This review aims to describe how a vitamin D research strategy, fully integrating all aspects of present-day AD research, would elucidate the genetic, molecular, and biochemical background of the disease.

Pre-operative biomarkers and imaging tests as predictors of post-operative delirium in non-cardiac surgical patients: a systematic review

Background

Post-operative delirium (POD) is a common post-operative complication in elderly individuals and imposes a significant health and financial burden. Identifying predictive biomarkers may help understand the pathophysiology of POD. Our objective is to summarize the evidence of pre-operative biomarkers and imaging tests to predict POD in patients undergoing non-cardiac surgery.

Methods

A systematic search of English language articles in MEDLINE, EMBASE, Cochrane Database, PsychINFO, PubMed and ClinicalTrials. Gov up to January 2018 was performed. Studies that used biomarkers or imaging tests to predict POD and a validated POD assessment tool were included. Animal studies, paediatric, cardiac and intracranial surgery were excluded. Risk of bias was assessed using the Quality In Prognosis Study tool.

Results

Thirty-four prospective cohort studies involving 4424 patients were included. Nineteen studies described serum tests [Interleukin-6, Insulin-like Growth Factor 1, C-Reactive Protein (CRP), cholinesterases, apolipoprotein-E genotype, leptin, hypovitaminosis, hypoalbuminaemia, gamma-amino butyric acid], 10 described cerebral-spinal fluid tests (monoamine precursor, melatonin, acute phase proteins, S100B and neurofibrillary tangles), and 5 described imaging tests. Two studies had high risk of bias due to unclear outcome measurement and study participation. CRP was significantly associated with POD in 5 studies. Other biomarkers were either examined by only a single study or two or more studies with conflicting results.

Conclusion

CRP is the most promising biomarker associated with POD. However, we are still in the early stages in identifying biomarkers and imaging tests that may further understanding of the pathophysiology of POD.

Electronic supplementary material

The online version of this article (10.1186/s12871-019-0693-y) contains supplementary material, which is available to authorized users.

Vitamin D Status and Intakes and Their Association With Cognitive Trajectory in a Longitudinal Study of Urban Adults

CONTEXT

Serum 25-hydroxyvitamin D [25(OH)D], and dietary and supplemental vitamin D may influence cognitive outcomes.

OBJECTIVES

Sex-, age-, and race-specific associations of vitamin D status and intake with longitudinal change in various cognitive domains were examined in a large sample of ethnically and socioeconomically diverse US urban adults.

DESIGN

Two prospective waves of data from the Healthy Aging in Neighborhoods of Diversity across the Life Span study were used.

PARTICIPANTS

Adults in Baltimore, Maryland, aged 30 to 64 years at baseline (n = 1231 to 1803), were followed for a mean (± standard deviation) of 4.64 ± 0.93 years. Visit 1 occurred between 2004 and 2009; visit 2, between 2009 and 2013; there were 1.5 to 2.0 visits per participant.

MAIN OUTCOME AND EXPOSURE MEASURES

Cognitive performance was assessed using 11 test scores covering domains of global cognition, attention, learning/memory, executive function, visuospatial/visuoconstruction ability, psychomotor speed, and language/verbal. Serum 25(OH)D, vitamin D intake, and use of supplements containing vitamin D were the key exposures.

RESULTS

A consistent relationship was found between vitamin D status (overall) and supplemental intake (older women and black adults), with a slower rate of decline in the domain of verbal fluency. Higher dietary intake of vitamin D was linked to slower rate of decline in verbal memory among younger women, and a slower rate of decline in visual memory/visuoconstructive abilities among white adults. All other associations were inconsistent.

CONCLUSIONS

Vitamin D status and intakes were inversely related to domain-specific cognitive decline in US urban adults.

Vitamin D, Cognition and Alzheimer's Disease: The Therapeutic Benefit is in the D-Tails

Since its discovery during the epidemic of rickets in the early 1920s, the physiological effects of vitamin D on calcium/phosphorus homeostasis have been thoroughly studied. Along with the understanding of its actions on skeletal diseases and advances in cellular and molecular biology, this misnamed vitamin has gained attention as a potential player in a growing number of physiological processes and a variety of diseases. During the last 25 years, vitamin D has emerged as a serious candidate in nervous system development and function and a therapeutic tool in a number of neurological pathologies. More recently, experimental and pre-clinical data suggest a link between vitamin D status and cognitive function. Human studies strongly support a correlation between low levels of circulating 25-hydroxyvitamin D (25(OH)D) and cognitive impairment or dementia in aging populations. In parallel, animal studies show that supplementation with vitamin D is protective against biological processes associated with Alzheimer’s disease (AD) and enhances learning and memory performance in various animal models of aging and AD. These experimental observations support multiple mechanisms by which vitamin D can act against neurodegenerative processes. However, clinical interventional studies are disappointing and fail to associate increased 25(OH)D levels with improved cognitive outcomes. This review collects the current available data from both animal and human studies and discusses the considerations that future studies examining the effects of vitamin D status on neurocognitive function might consider.

Vitamin D and Neurological Diseases: An Endocrine View

Vitamin D system comprises hormone precursors, active metabolites, carriers, enzymes, and receptors involved in genomic and non-genomic effects. In addition to classical bone-related effects, this system has also been shown to activate multiple molecular mediators and elicit many physiological functions. In vitro and in vivo studies have, in fact, increasingly focused on the "non-calcemic" actions of vitamin D, which are associated with the maintenance of glucose homeostasis, cardiovascular morbidity, autoimmunity, inflammation, and cancer. In parallel, growing evidence has recognized that a multimodal association links vitamin D system to brain development, functions and diseases. With vitamin D deficiency reaching epidemic proportions worldwide, there is now concern that optimal levels of vitamin D in the bloodstream are also necessary to preserve the neurological development and protect the adult brain. The aim of this review is to highlight the relationship between vitamin D and neurological diseases.

Vitamin D Receptor Regulates Amyloid Beta 1-42 Production with Protein Disulfide Isomerase A3

The challenge of understanding the biology of neuronal amyloid processing could provide a basis for understanding the amyloid pathology in Alzheimer's disease (AD). Based on our previous studies, we have suggested that AD might be the consequence of a hormonal imbalance in which the critical hormone is vitamin D. The present study primarily focused on the creation of a condition that prevents the genomic or nongenomic action of vitamin D by disrupting vitamin D receptors (VDR or PDIA3/1,25MARRS); the effects of these disruptions on the series of proteins involved in secretases that play a crucial role in amyloid pathology and on amyloid beta (Aβ) production in primary cortical neurons were observed. VDR and PDIA3/1,25MARRS genes were silenced separately or simultaneously in E16 primary rat cortical neurons. The expression of target genes involved in APP processing, including Presenilin1, Presenilin2, Nicastrin, BACE1, ADAM10, and APP, was investigated with qRT-PCR and Western blot in this model. 1,25-Dihydroxyvitamin D₃ treatments were used to verify any transcriptional regulation data gathered from siRNA treatments by determining the mRNA expression of the target genes. Immunofluorescence labeling was used for the verification of silencing experiments and intracellular Aβ1-42 production. Extracellular Aβ1-42 level was assessed with ELISA. mRNA and protein expression results showed that 1,25-dihydroxyvitamin D₃ might affect the transcriptional regulation of the genes involved in APP processing. The intracellular and extracellular Aβ1-42 measurements in our study support this suggestion. Consequently, we suggest that 1,25-dihydroxyvitamin D₃ and its receptors are important parts of the amyloid processing pathway in neurons.

Role of Vitamin D in Amyloid clearance via LRP-1 upregulation in Alzheimer's disease: A potential therapeutic target?

Amyloid beta (Aβ) deposition is considered to be one of the primary reason to trigger Alzheimer's disease (AD). Literature clearly suggests decline in Aβ clearance to be accountable for progression of late onset AD as compared to augmented Aβ production. There may be several pathways for Aβ clearance out of which one of the major pathway is the vascular-mediated removal of Aβ from the brain across the blood-brain barrier (BBB) via efflux pumps or receptors. Among Aβ scavenger receptors, low density lipoprotein receptor related protein (LRP-1) has been most extensively studied. LRP-1, is highly expressed in neurons and located on abluminal side of the brain capillaries whose expression decreases in AD patients which give rise to increased cerebral Aβ deposition. Recent evidences reveal that post 1,25-(OH)₂D₃ treatment, LRP1 expression increases significantly for both in-vivo and in-vitro studies, since Vitamin D receptors (VDR) are broadly expressed in brain. Biological actions of Vitamin D are mediated via its nuclear hormone receptor vitamin D receptor (VDR) and is found to regulate many genes. Several lines of evidence suggest that VDR deficiency/inhibition can be a potential risk factor for AD and sufficient Vitamin D supplementation is beneficial to prevent AD onset/pathology or slow down the progression of disease. The present review establishes a strong correlation between Vitamin D and LRP-1 and their possible involvement in Aβ clearance and thereby emerging as new therapeutic target.

Association between physical activity and vitamin D: A narrative literature review

Summary This narrative review of the medical literature assessed whether outdoor and indoor physical activity would increase the plasma levels of vitamin D. Synthesis of this liposoluble vitamin is mainly mediated by sunlight on the skin, where it is activated to perform its main action, which is to control the serum levels of calcium as soon as the element is absorbed in the intestines, assisting in the regulation of bone metabolism. Physical activity is any body movement that results in energy expenditure, while outdoor physical activity refers to physical activity carried out at public parks or other open spaces, as is the case of the popular practice of taking walks. Exercising outdoors would have both the benefits of physical activity and of sun exposure, namely the synthesis of vitamin D. However, according to the studies analyzed, increased plasma concentration of vitamin D occurs with physical activity both indoors and outdoors.

Role of Pro-Inflammatory Cytokines and Vitamin D in Probable Alzheimer's Disease with Depression

Symptoms of depression are present in a significant proportion of Alzheimer's disease (AD) patients. While epidemiological studies have shown a strong association between depression and AD, it has not been established whether depression is a risk factor or merely a co-morbidity of AD. It is also uncertain if depression affects the pathogenesis of AD. In this paper, we address these questions by measuring the serum levels of two common metabolic risk factors of AD and depression, inflammatory cytokines (IL 6 and TNF alpha) and serum 25-hydroxyvitamin D, in a case-control study. We measured the serum levels of IL 6, TNF α and 25-hydroxyvitamin D in age-matched healthy controls (n= 60) and in AD patients without depression (n=26) or AD patients with depression (n=34), and statistically analyzed the changes in these parameters among different groups under this study. Our results show that in AD there is a significant increase in IL 6 and TNF α and a marked decrease in 25-hydroxyvitamin D in the peripheral circulation compared to age-matched healthy controls. Furthermore, AD patients with depression have even significantly higher levels of IL 6 or TNF α and a lower level of 25-hydroxyvitamin D in circulation than in AD patients without depression. We also found a strong statistical correlation between the disease severity and the serum levels of IL 6, TNF α and 25-hydroxyvitamin D in AD patients with depression. These results suggest that altered circulating levels of common metabolic risk factors lead to the co-existence of depression with AD in many patients, and when they co-exist, the depression presumably affects the severity of AD presentations through more aggravated changes in these risk factors.

Effect of Vitamin D Replacement on Cognition in Multiple Sclerosis Patients

Multiple Sclerosis is associated with deficient serum 25 hydroxyvitamin D (25 (OH)D) level and cognitive impairment. The aim of this study is to evaluate cognitive performance in MS patients with deficient 25 (OH)D (<25 ng/ml) compared to patients with sufficient levels (>35 ng/ml), then to evaluate the change in cognitive performance after 3 months of vitamin D3 oral replacement. Eighty-eight MS patients with relapsing remitting and clinically isolated type of MS, older than 18 years treated with interferon beta were enrolled. Cognitive testing was performed at baseline and at 3 months using the Montreal Cognitive Assessment (MoCA), Stroop, Symbol Digit Modalities (SDMT) and Brief Visuospatial Memory Test (BVMT-R). Serum 25 (OH)D was measured at baseline and at the end of the study. Vitamin D3 replacement improved the MS patients' cognitive performance after 3 months on the MoCA and BVMT-Delayed Recall (DR). Sufficient serum 25 (OH)D level predicted better cognitive performance on the BVMT-DR at baseline (β: 1.74, p: <0.008) and 3 months (β: 1.93, p: <0.01) after adjusting for all measured confounding variables. Vitamin D₃ replacement could improve cognitive performance in MS patients and make a significant difference in the patient's quality of life.

Association of circulating 25-hydroxyvitamin D with mental well-being in a population-based, nationally representative sample of German adolescents

OBJECTIVE

Numerous studies have linked vitamin D to health-related quality of life (hrQoL) in chronically ill adults or elderly subjects. The aim of this study was to evaluate the association between 25-hydroxyvitamin D (25(OH)D) and hrQoL in a population-based sample of German adolescents.

METHODS

A total of n = 5066 study participants from the nationwide, representative German Health Interview and Examination Survey for Children and Adolescents (Kinder- und Jugendgesundheitssurvey) aged 11-17 years were included in this post hoc analysis. HrQoL was measured using the well-validated self- and parent-rated Children's Quality of Life questionnaires (KINDL-R), while the level of distress was assessed using the self- and proxy version of the Strengths and Difficulties Questionnaire (SDQ). Serum 25(OH)D concentrations were determined using a commercially available chemiluminescence immunoassay.

RESULTS

Bivariate analyses demonstrated a significant positive association between 25(OH)D and hrQoL for both self- [estimate (E) = 0.82, 95 % confidence interval (95 % CI) 0.35-1.30, p = 0.001] and parent ratings (E = 1.33, 95 % CI 0.83-1.83, p < 0.001). In addition, we found negative correlations between 25(OH)D and self- (E = -0.34, 95 % CI -0.58 to -0.11, p = 0.005) and parent-reported total SDQ scores (E = -0.70, 95 % CI -1.03 to -0.37, p < 0.001). Generalized linear models adjusted for age, sex, body mass index, systolic blood pressure, migration background, socio-economic status, and sedentary screen time confirmed that 25(OH)D independently and significantly predicted better hrQoL (p ≤ 0.004).

CONCLUSIONS

These findings linking 25(OH)D to better well-being in a nationally representative sample of German children and adolescents suggest beneficial effects of vitamin D on mental health. However, recommendations for vitamin supplementation in healthy children and adolescents are not warranted from our data.

Nutrient Intake and Depression Symptoms in Spanish Children: The ANIVA Study

The aim of this study was to examine the relationship between nutritional intake and depressive symptoms in Valencian schoolchildren. The ANIVA (Antropometria y Nutricion Infantil de Valencia) study is a descriptive cross-sectional study. During academic year 2013–2014, 710 schoolchildren aged 6–9 years were selected from eleven primary schools in Valencia (Spain). Children’s dietary intake was measured on three-day food records, completed by parents/guardians; children completed the 20-item Center for Epidemiologic Studies Depression Scale for Children (CES-DC) Questionnaire to measure depressive symptoms. Weight, height, and body mass index (BMI), and z-scores were evaluated in all subjects. Nutrient adequacy was assessed using Spanish dietary recommended intakes (DRIs); 20.70% of the sample presented depressive symptoms. We identified a positive association between children with depressive symptoms and non-depressive symptoms for thiamin, vitamin K, and bromine (p < 0.05), and a negative association for protein, carbohydrates, pantothenic acid, biotin, vitamin B₁₂ and E, zinc, manganese, cobalt, and aluminum (p < 0.05). Statistically significant differences were found between both groups according to the DRIs for intakes of total energy (p = 0.026), fiber (p < 0.001), vitamin C (p < 0.001), vitamin E (p = 0.004), magnesium (p = 0.018), and iron (p = 0.013). Our results demonstrated that carbohydrates were the most closely associated factor with depressive symptoms, and highlight the potential significant public health implications of inadequate nutritional intake on schoolchildren’s mental health.

Sex-specific attentional deficits in adult vitamin D deficient BALB/c mice

Epidemiological studies have shown an association between vitamin D deficiency and cognitive impairment. However, there is a paucity of preclinical data showing that vitamin D deficiency is a causal factor for impaired cognitive processing. The aim of this study was to assess two cognitive tasks, the 5 choice-serial reaction task and the 5 choice-continuous performance task in adult vitamin D (AVD) deficient BALB/c mice. Ten-week old male and female BALB/c mice were fed a control or vitamin D deficient diet for 10 weeks prior to, and during behavioural testing. We found sex-dependent impairments in attentional processing and showed that male AVD-deficient mice were less accurate, took longer to respond when making a correct choice and were more likely to make an omission, without a change in the motivation to collect reward. By contrast, female AVD-deficient mice had a reduced latency to collect reward, but no changes on any other measures compared to controls. Therefore, we have shown that in otherwise healthy adult mice, vitamin D deficiency led to mild cognitive impairment in male but not female mice and therefore this model will be useful for future investigations into unravelling the mechanism by which vitamin D affects the adult brain and cognitive function.

Vitamin D and Memory Decline: Two Population-Based Prospective Studies

BACKGROUND

Vitamin D deficiency has been linked with dementia risk, cognitive decline, and executive dysfunction. However, the association with memory remains largely unknown.

OBJECTIVE

To investigate whether low serum 25-hydroxyvitamin D (25(OH)D) concentrations are associated with memory decline.

METHODS

We used data on 1,291 participants from the US Cardiovascular Health Study (CHS) and 915 participants from the Dutch Longitudinal Aging Study Amsterdam (LASA) who were dementia-free at baseline, had valid vitamin D measurements, and follow-up memory assessments. The Benton Visual Retention Test (in the CHS) and Rey's Auditory Verbal Learning Test (in the LASA) were used to assess visual and verbal memory, respectively.

RESULTS

In the CHS, those moderately and severely deficient in serum 25(OH)D changed -0.03 SD (95% CI: -0.06 to 0.01) and -0.10 SD (95% CI: -0.19 to -0.02) per year respectively in visual memory compared to those sufficient (p = 0.02). In the LASA, moderate and severe deficiency in serum 25(OH)D was associated with a mean change of 0.01 SD (95% CI: -0.01 to 0.02) and -0.01 SD (95% CI: -0.04 to 0.02) per year respectively in verbal memory compared to sufficiency (p = 0.34).

CONCLUSIONS

Our findings suggest an association between severe vitamin D deficiency and visual memory decline but no association with verbal memory decline. They warrant further investigation in prospective studies assessing different memory subtypes.

Vitamin D and Alzheimer's Disease: Neurocognition to Therapeutics

Alzheimer's disease (AD), the major cause of dementia worldwide, is characterized by progressive loss of memory and cognition. The sporadic form of AD accounts for nearly 90% of the patients developing this disease. The last century has witnessed significant research to identify various mechanisms and risk factors contributing to the complex etiopathogenesis of AD by analyzing postmortem AD brains and experimenting with animal and cell culture based models. However, the treatment strategies, as of now, are only symptomatic. Accumulating evidences suggested a significant association between vitamin D deficiency, dementia, and AD. This review encompasses the beneficial role of vitamin D in neurocognition and optimal brain health along with epidemiological evidence of the high prevalence of hypovitaminosis D among aged and AD population. Moreover, disrupted signaling, altered utilization of vitamin D, and polymorphisms of several related genes including vitamin D receptor (VDR) also predispose to AD or AD-like neurodegeneration. This review explores the relationship between this gene-environmental influence and long term vitamin D deficiency as a risk factor for development of sporadic AD along with the role and rationale of therapeutic trials with vitamin D. It is, therefore, urgently warranted to further establish the role of this potentially neuroprotective vitamin in preventing and halting progressive neurodegeneration in AD patients.

The association of vitamin D deficiency with psychiatric distress and violence behaviors in Iranian adolescents: the CASPIAN-III study

Background

Subtle effects of vitamin D deficiency on behavior have been suggested. We investigated the association of vitamin D status with mental health and violence behaviors in a sample of Iranian adolescents.

Methods

This nationwide study was conducted in 2009–2010 in 1095 Iranian school students with mean age 14.7 ± 2.6 years. Items were adapted from the Global School-based Student Health Survey (GSHS). Psychiatric distress was considered as the self-reported anger, anxiety, poor quality sleep, confusion, sadness/depression, worry, and violence-related behaviors (physical fight, having bully, or getting bullied).

Results

Forty percent had serum 25(OH)D values below 10 ng/mL (vitamin D deficient), and 39 % had levels 10-30 ng/mL (vitamin D insufficient). The prevalence of self-reported anger, anxiety, poor quality sleep, sadness/depression, and worry was significantly lower (P < 0.05) in vitamin D sufficient participants compared with their other counterparts. The odds of reporting anger, anxiety, poor quality sleep, and worry, increased approximately 1.5 to 1.8 times in vitamin D insufficient compared with normal children and adolescents (P < 0.05). Risk estimates indicated that vitamin D insufficient and deficient subjects had higher odds of reporting worry compared to normal vitamin D group [OR = 2.417 (95 % CI: 1.483-3.940) for vitamin D insufficient students, and OR = 2.209 (95 % CI: 1.351-3.611) for vitamin D deficient students] (P-trend = 0.001). Violence behaviors did not show any association with vitamin D status (P > 0.05).

Conclusion

Some psychiatric distress such as anger, anxiety, poor quality sleep, depression, and worry are associated with hypovitaminosis D in adolescents. The clinical significance of the current findings should be determined in future longitudinal studies.

Effect of a monthly dose of calcidiol in improving vitamin D deficiency and secondary hyperparathyroidism in HIV-infected patients

There are no data about the optimal supplementation therapy in HIV-infected patients with vitamin D (25OHD) deficiency. The aim of this study was to assess the effect of an oral monthly dose of 16,000 IU calcidiol. We performed a longitudinal cohort study of 365 HIV-infected patients (24 % females) was with sequential determinations of 25OHD, serum parathyroid hormone (PTH), calcium, and alkaline phosphatase. The efficacy and safety of supplementation in 123 patients were compared against dietary and sun exposure advice. Overall, mean baseline 25OHD levels were 19.1 ng/ml (IQR 12-23.6), 63 % of patients had 25OHD deficiency and 27 % secondary hyperparathyroidism. After a median time of 9.3 months (95.61 patients-year on-treatment), 25OHD levels increased in comparison with non-supplemented patients (+16.4 vs. +3.2 ng/ml; p < 0.01), decreasing the rate of 25OHD deficiency (from 84 to 24 %), and decreasing serum PTH (-4.9 pg/ml) and the rate of secondary hyperparathyroidism (from 43 to 31 %; p < 0.001). This improvement was observed irrespective of HIV/HCV coinfection or the use of efavirenz. In a regression analysis, adjusting by seasonality, a lower baseline 25OHD was associated with persistence of deficiency (relative risk, RR 1.07; 95 % CI 1.03-1.1; p < 0.001), whereas calcidiol supplementation was the only factor associated with significant improvement (RR 0.38; 95 % CI 0.12-0.46; p < 0.001). This monthly dose showed no clinical toxicity, and no patient had 25OHD levels above 100 ng/ml, nor hypercalcemia. The use of monthly calcidiol is safe, easy to take, and largely effective to improve vitamin D deficiency and secondary hyperparathyroidism in HIV-infected patients.

Serum 25-hydroxyvitamin D and cognitive decline: a longitudinal study among non-demented older adults

BACKGROUND/AIMS

Very few studies have investigated the longitudinal association between serum levels of 25-hydroxyvitamin D [25(OH)D] and cognitive impairment not due to dementia. This longitudinal study analysed 25(OH)D and the risk of cognitive decline among non-demented older adults.

METHODS

A subsample of the ESTHER cohort study, aged ≥70 years, was assessed with the Cognitive Telephone Screening Instrument (COGTEL) and underwent 25(OH)D measurements standardized with a reference method (n = 1,302). After an average follow-up of 4.6 years, 527 participants had repeated COGTEL testing and were eligible for analysis. Linear regression models were used to assess longitudinal associations between 25(OH)D levels and cognitive function. Possible practice effects of repeated cognitive testing were addressed with the reliable change index.

RESULTS

A trend of a more pronounced cognitive decline with lower vitamin D levels was observed among both women and men, with a statistically significant difference in COGTEL scores in the lowest vitamin D quintile of the total sample.

CONCLUSIONS

This study indicates that low levels of vitamin D might be associated with cognitive decline among non-demented elderly individuals and highlights the need for further large-scale prospective studies to clarify the potential role of vitamin D in cognitive function at an old age.

Coastal climate is associated with elevated solar irradiance and higher 25(OH)D level

INTRODUCTION

There is evidence that populations living close to the coast have improved health and wellbeing. Coastal environments are linked to promotion of physical activity through provision of safe, opportune, aesthetic and accessible spaces for recreation. Exposure to coastal environments may also reduce stress and induce positive mood. We hypothesised that coastal climate may influence the vitamin D status of residents and thus partly explain benefits to health.

MATERIALS AND METHODS

Ecological and cross-sectional analyses were designed to elucidate the connection between coastal residence and vitamin D status. We divided residential data, from developed land use areas and the Lower Super Output Areas or Data Zones (Scotland) of the 1958 Birth Cohort participants, into the following coastal bands: <1 km, 1-5 km, 5-20 km, 20-50 km and over 50 km. In the ecological analysis we used a multiple regression model to describe the relationship between UV vitd and coastal proximity adjusted for latitude. Subsequently, using the residential information of the participants of the 1958 Birth Cohort we developed a multiple regression model to understand the relationship between serum 25(OH)D (a marker of vitamin D status) and coastal proximity adjusted for several factors related to vitamin D status (e.g. diet, outdoor activity).

RESULTS

We found that coastal proximity was associated with solar irradiance; on average a 99.6 (96.1-103.3)J/m(2)/day regression coefficient was recorded for settlements <1 km from the coast compared with those at >50 km. This relationship was modified by latitude with settlements at a lower latitude exhibiting a greater effect. Individuals living closer to the coast in England had higher vitamin D levels than those inland, particularly in autumn.

CONCLUSION

Geographic location may influence biochemistry and health outcomes due to environmental factors. This can provide benefits in terms of vitamin D status but may also pose a risk due to higher skin cancer risk. We provide further evidence in support of the claim that coastal environments can provide opportunities for health and wellbeing.

Vitamin D as a neurosteroid affecting the developing and adult brain

Vitamin D deficiency is prevalent throughout the world, and growing evidence supports a requirement for optimal vitamin D levels for the healthy developing and adult brain. Vitamin D has important roles in proliferation and differentiation, calcium signaling within the brain, and neurotrophic and neuroprotective actions; it may also alter neurotransmission and synaptic plasticity. Recent experimental studies highlight the impact that vitamin D deficiency has on brain function in health and disease. In addition, results from recent animal studies suggest that vitamin D deficiency during adulthood may exacerbate underlying brain disorders and/or worsen recovery from brain stressors. An increasing number of epidemiological studies indicate that vitamin D deficiency is associated with a wide range of neuropsychiatric disorders and neurodegenerative diseases. Vitamin D supplementation is readily available and affordable, and this review highlights the need for further research.