Vitamin D concentration and focal brain atrophy in older adults: a voxel-based morphometric study

Brain function mediates the association between low vitamin D and neurocognitive status in female patients with major depressive disorder

BACKGROUND

Vitamin D is engaged in various neural processes, with low vitamin D linked to depression and cognitive dysfunction. There are gender differences in depression and vitamin D level. However, the relationship between depression, gender, vitamin D, cognition, and brain function has yet to be determined.

METHODS

One hundred and twenty-two patients with major depressive disorder (MDD) and 119 healthy controls underwent resting-state functional MRI and fractional amplitude of low-frequency fluctuations (fALFF) was calculated to assess brain function. Serum concentration of vitamin D (SCVD) and cognition (i.e. prospective memory and sustained attention) were also measured.

RESULTS

We found a significant group-by-gender interaction effect on SCVD whereby MDD patients showed a reduction in SCVD relative to controls in females but not males. Concurrently, there was a female-specific association of SCVD with cognition and MDD-related fALFF alterations in widespread brain regions. Remarkably, MDD- and SCVD-related fALFF changes mediated the relation between SCVD and cognition in females.

CONCLUSION

Apart from providing insights into the neural mechanisms by which low vitamin D contributes to cognitive impairment in MDD in a gender-dependent manner, these findings might have clinical implications for assignment of female patients with MDD and cognitive dysfunction to adjuvant vitamin D supplementation therapy, which may ultimately advance a precision approach to personalized antidepressant choice.

Vitamin D deficit is associated with accelerated brain aging in the general population

Vitamin D deficiency has been associated with reduced neurocognitive functioning and the neurodegenerative processes. However, existing evidence on brain structural correlates of vitamin D deficiency is controversial. We sought to investigate associations of vitamin D levels with imaging patterns of brain aging. In addition, we investigated whether low vitamin D levels were associated with gray matter volumes, whole brain volumes and hippocampus volumes. Structural MRI data and vitamin D levels were obtained in 1,865 subjects from the general population. Linear regressions were applied to investigate the association of vitamin D levels and vitamin D deficiency with imaging derived brain age, total brain, gray matter and hippocampal volumes. Different sets of covariates were included. Vitamin D deficiency was significantly associated with increased brain age. Also, linear vitamin D levels were significantly associated with total brain and gray matter volumes, while no significant association with hippocampal volume was found. Further interaction analyses showed that this association was only significant for male subjects. Our results support previous findings suggesting that vitamin D-deficient individuals have an accelerated brain aging. In addition, associations between vitamin D levels and total brain/ gray matter volumes suggest neuroprotective effects of vitamin D on the brain.

Vitamin D Concentration and Motoric Cognitive Risk in Older Adults: Results from the Gait and Alzheimer Interactions Tracking (GAIT) Cohort

BACKGROUND

Motoric Cognitive Risk (MCR) syndrome, which combines subjective memory complaint (SMC) and slower gait speed, is a newly-described predementia stage. Based on the involvement of vitamin D in the biology of both gait and cognition, we hypothesized that nondemented individuals with MCR would exhibit hypovitaminosis D more often compared to Cognitively Healthy Individuals (CHI). The objective of this cross-sectional analysis was to determine whether hypovitaminosis D was associated with MCR.

METHODS

Participants without dementia from the GAIT (Gait and Alzheimer Interactions Tracking) cohort study were classified into MCR or Cognitively Healthy Individuals (CHI) groups. Hypovitaminosis D was defined as the lowest quartile of serum 25-hydroxyvitamin D (25OHD) concentration compared to the other three combined. Age, sex, body mass index (BMI), the Frontal Assessment Battery (FAB) score, the Mini-Mental Short Examination (MMSE) score, education level, use of psychoactive drugs, and the number of chronic diseases were used as covariates.

RESULTS

Among 244 nondemented and nonMCInonMCR participants from the GAIT cohort (mean age 71.4 ± 3.7 years, 40.6% women), 66 participants were classified as MCR (36.9%) and 178 as CHI (63.1%). The lowest quartile of 25OHD concentration was directly associated with MCR (unadjusted OR = 2.85, p = 0.003) even after adjustment for studied potential confounders (fully adjusted OR = 2.61, p = 0.025). The BMI (adjusted OR = 6.65, p < 0.001), MMSE score (adjusted OR = 0.74, p = 0.009), FAB score (adjusted OR = 0.51, p < 0.001), number of chronic diseases (adjusted OR = 1.29, p = 0.043) and use of psychoactive drugs (adjusted OR = 2.55, p = 0.044) were also associated with MCR.

CONCLUSIONS

Hypovitaminosis D was associated with MCR in older community-dwellers without dementia.

The reduction of vitamin D in females with major depressive disorder is associated with worse cognition mediated by abnormal brain functional connectivity

Low vitamin D is linked to major depressive disorder (MDD) through affecting the brain. Gender difference is apparent in MDD and vitamin D level. We aimed to examine the association between gender, vitamin D, clinical presentations, and brain functional connectivity in a large cohort of MDD patients and comparison subjects. Resting-state functional MRI data from 122 patients and 119 controls were collected to perform a combined analysis of functional connectivity density (FCD) and seed-based functional connectivity (FC). Peripheral venous blood samples were obtained to measure serum concentration of vitamin D (SCVD). Clinical presentations (symptoms profiles and cognition) were also assessed. We found an interaction of group and gender on SCVD in which MDD patients demonstrated lower SCVD than controls in females rather than males. Concurrently, lower SCVD was associated with worse cognitive performance (prospective memory and sustained attention). Compared with controls, female MDD patients showed reduced FCD and FC of the left middle frontal gyrus, which were related to lower SCVD. Importantly, these FCD and FC changes mediated the relationship between lower SCVD and cognitive dysfunction. Our findings suggest that functional connectivity abnormalities may serve as neural substrates underlying the associations between low vitamin D and cognitive impairments in female MDD patients, providing unique insight into treatment and prevention of MDD and its related cognitive dysfunction from the perspective of regulating circulating vitamin D.

The Relationship Between Vitamin D, Clinical Manifestations, and Functional Network Connectivity in Female Patients With Major Depressive Disorder

Evidence suggests the pivotal role of vitamin D in the pathophysiology of major depressive disorder (MDD) via its effects on the brain. Gender differences exist in both depression and vitamin D level. Our objective was to investigate the association between gender, vitamin D, clinical manifestations, and functional network connectivity in a large sample of MDD patients and healthy controls. Resting-state functional MRI data were collected from 122 patients and 119 controls, with independent component analysis adopted to examine large-scale inter- and intranetwork functional connectivity. Serum concentration of vitamin D (SCVD) and clinical manifestations were also assessed. MDD patients exhibited lower SCVD than controls in females but not males. Moreover, we identified a female-specific association between lower SCVD and poorer cognitive performance. Concurrently, MDD-related functional network connectivity changes were correlated with SCVD in females as well as depression and anxiety symptoms in female patients. Remarkably, MDD- and SCVD-related functional network connectivity alterations mediated the associations between SCVD and cognition in females. Aside from providing evidence for a female-specific neurobiological mechanism whereby low vitamin D might contribute to MDD and its associated clinical characteristics, our findings inform a novel conceptualization that adjuvant vitamin D supplementation therapy may yield clinical benefits in improving treatment outcomes in female patients with MDD.

A Novel Method for the Determination of Vitamin D Metabolites Assessed at the Blood-Cerebrospinal Fluid Barrier

The brain’s supply with vitamin D is poorly understood. Therefore, the present study aimed to determine 25-hydroxy vitamin D3 (25(OH)D) and 24,25-dihydroxy vitamin D (24,25(OH)₂D₃) in serum and cerebrospinal fluid (CSF) from individuals with intact and disturbed brain-CSF-barrier (BCB) function. In 292 pairs of serum and CSF samples the vitamin D metabolites were measured with liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). CSF/serum ratios (Q_ALB, Q_25(OH)D, Q_24,25(OH)2D3) were calculated. Median (IQR) serum concentrations of 25(OH)D and 24,25(OH)₂D₃ were 63.8 (43.4–83.9) nmol/L and 4.2 (2.2–6.2) nmol/L. The CSF concentrations of both metabolites accounted for 3.7 and 3.3% of the respective serum concentrations. Serum 25(OH)D correlated inversely with Q_25(OH)D and Q_24,25(OH)2D3 implying a more efficient transport of both metabolites across the BCB when the serum concentration of 25(OH)D is low. In patients with BCB dysfunction, the CSF concentrations and the CSF/serum ratios of both vitamin D metabolites were higher than in individuals with intact BCB. The CSF concentrations of 25(OH)D and 24,25(OH)₂D₃ depend on BCB function and the respective serum concentrations of both metabolites. Higher vitamin D metabolite concentrations in CSF of patients with impaired BCB function may be due to passive diffusion across the BCB.

Associations between gait speed and brain structure in amnestic mild cognitive impairment: a quantitative neuroimaging study

BACKGROUND

Patients with amnestic mild cognitive impairment (aMCI) present gait disturbances including slower speed and higher variability when compared to cognitively healthy individuals (CHI). Brain neuroimaging could explore higher levels of motor control. Our purpose was to look for an association between morphometrics and gait parameters in each group. We hypothesized that the relation between morphological cerebral alteration and gait speed are different following the group.

METHODS

Fifty-three participants (30 with aMCI and 23 CHI) were recruited in this French cross-sectional study (mean 72 ± 5 years, 38% female). Gait speed and gait variability (coefficients of variation of stride time (STV) and stride length (SLV)) were measured using GAITrite® system. CAT12 software was used to analyse volume and surface morphometry like gray matter volume (GMV) and cortical thickness (CT). Age, gender and education level were used as potential cofounders.

RESULTS

aMCI had slower gait speed and higher STV when compared to CHI. In aMCI the full adjusted linear regression model showed that lower gait speed was associated with decreased GMV and lower CT in bilateral superior temporal gyri (p < 0.36). In CHI, no association was found between gait speed and brain structure. Higher SLV was correlated with reduced GMV in spread regions (p < 0.05) and thinner cortex in the middle right frontal gyrus (p = 0.001) in aMCI. In CHI, higher SLV was associated with reduced GMV in 1 cluster: the left lingual (p = 0.041).

CONCLUSIONS

These findings indicate that lower gait speed is associated with specific brain structural changes as reduced GMV and CT during aMCI.

Association of 25-hydroxyvitamin D status with brain volume changes

Vitamin D is critical to brain function and its deficiency accelerates cognitive impairment. There is limited understanding of the brain-specific areas that undergo volume change in relation to blood vitamin D levels. The objective of this study was to evaluate the association between blood 25-hydroxyvitamin D (25(OH)D) concentration and structural changes in the brain. We analyzed structural three-dimensional T1 MRI images of 201 elderly individuals (mean age = 74.91 ± 9.21 years; 68.1% female; mean 25(OH)D = 18.05 nmol/L), with 10 community-based normal healthy subjects, 33 with subjective cognitive decline, 97 with mild cognitive impairment, and 61 with Alzheimer's disease (AD). To analyze the structural changes in the brain respective to blood 25(OH)D, multiple regression analyses were performed using voxel-based morphometry with age and total intracranial volume as covariates. Lower 25(OH)D level were associated with reduced brain volume in right olfactory, rectus GM regions (FWE-corr, p < .05) for entire subjects. For AD subjects, left parahippocampal, fusiform, and hippocampal areas were positively associated with 25(OH)D (FWE-corr, p < .05). Low blood 25(OH)D was associated with reduced volumes in olfactory and hippocampal regions in elderly patients with cognitive decline. Our results may provide insight into the neurological pathophysiology of vitamin D.

Association of vitamin D metabolites with cognitive function and brain atrophy in elderly individuals - the Austrian stroke prevention study

BACKGROUND

Vitamin D is a well-established regulator of calcium and phosphate metabolism that has neurotrophic and neuroprotective properties. Deficiency of vitamin D has been proposed to promote cognitive dysfunction and brain atrophy. However, existing studies provide inconsistent results. Here we aimed to investigate the association between vitamin D metabolites, cognitive function and brain atrophy in a cohort of well-characterized community-dwelling elderly individuals with normal neurological status and without history of stroke and dementia.

METHODS

25(OH)D3, 25(OH)D2 and 24,25(OH)2D3 were measured by liquid-chromatography tandem mass-spectrometry in serum samples from 390 community-dwelling elderly individuals. All participants underwent thorough neuropsychiatric tests capturing memory, executive function and visuopractical skills. In 139 of these individuals, MRI of the brain was performed in order to capture neurodegenerative and vascular changes.

RESULTS

Total 25(OH)D (ß=0.003, 0.037), 24,25(OH)2D3 (ß=0.0456, p=0.010) and vitamin D metabolite ratio (VMR) (ß=0.0467, p=0.012) were significantly related to memory function. Adjustment for multiple testing weakened these relationships, but trends (p≤0.10) remained. 24,25(OH)2D3 and VMR showed similar trends also for visuopractical skills and global cognitive function. No significant relationships existed between vitamin D metabolites and MRI derived indices of neurodegeneration and vascular changes. Sub-group analyses of individuals with low concentrations of 25(OH)D and 24,25(OH)2D3 showed significantly worse memory function compared to individuals with normal or high concentrations.

CONCLUSIONS

Vitamin D deficient individuals appear to have a modest reduction of memory function without structural brain atrophy. Future studies should explore if vitamin D supplementation can improve cognitive function.

Neuroimaging changes associated with vitamin D Deficiency - a narrative review

ABSTRACTEmerging evidence suggests the role of vitamin D in brain health and its implication in the pathogenesis of cognitive impairment. The Aim of this review is to summarize current evidence on neuroimaging changes seen in vitamin D deficient individuals. Cross-sectional and longitudinal studies have consistently found an association between low serum 25 hydroxyvitamin D and cognitive impairment. Furthermore, investigating the association between serum 25 hydroxyvitamin D and neuroimaging abnormalities could provide an insight into the potential mechanisms underlying the association with cognitive impairment. Animal studies have demonstrated structural changes in the cerebral cortex and hippocampus of vitamin D deficient mice. Neuroimaging studies of the brain have shown increased white matter hyperintensities in periventricular, cortical, and juxtacortical areas and grey matter atrophy of the hippocampus, anterior cingulate cortex, and left calcarine sulcus in elderly with vitamin D deficiency.