Higher Vitamin D Levels Are Associated with Better Attentional Functions: Data from the NorCog Register

Serum Vitamin-D Levels And Severity Of Clinical Depression In Patients Of A Psychiatric Clinic in Pakistan

Vitamin D deficiency is often correlated with nervous system disorders like major depression, Parkinson’s disease and dementia. While much of the clinical literature suggests its association with clinical depression, very few studies have looked into the relationship between vitamin D levels and clinical depression severity. Objectives: To find out the association between vitamin D levels in patients suffering from different severities of clinical depression with the confounding socio-cultural factors of a third-world country i.e., Pakistan. Methods: The cross-sectional study was conducted in Lady Reading Hospital, Peshawar for five months with convenience sampling. Results: Overall, the study had 132 (36.57%) males and 229 (63.43%) females, and 236 diagnosed cases of Clinical Depression. In terms of Vitamin D levels, 242 (67.04%) had deficient, while 77 (21.33%) and 42 (11.63%) had insufficient and normal vitamin D levels, respectively. There was a statistically significant difference in the serum Vitamin D levels between at least two groups (F (3,232) = [38.64], p < 0.05). Conclusions: Vitamin D levels showed a dose-dependent, inverse relation with the severity of clinical depression in the Pakistani population

Vitamin D in Alzheimer's Disease: Low Levels in Cerebrospinal Fluid Despite Normal Amounts in Serum

BACKGROUND

Vitamin D insufficiency has been suggested as a dementia risk factor.

OBJECTIVE

In this cross-sectional, explorative study we investigated whether levels of vitamin D in cerebrospinal fluid (CSF) are lower in patients with positive biomarkers of Alzheimer's disease (AD) compared to cognitively healthy controls and whether polymorphisms of the vitamin D receptor (VDR) gene, FokI, BsmI, ApaI, and TaqI, are associated with levels of vitamin D in CSF and cognition.

METHODS

We included 100 patients≥65 years assessed for cognitive impairment and 76 cognitively healthy controls. Levels of 25-hydroxyvitamin D (25(OH)D) in both serum and CSF, and VDR polymorphisms were analyzed.

RESULTS

The mean level of 25(OH)D in serum was 78.6 (SD 28.9) nmol/l. While serum levels of 25(OH)D were not significantly different between the groups, CSF levels of 25(OH)D were significantly lower in patients with positive AD core biomarkers (p = 0.001) compared to patients without such biomarkers. Individuals with the BsmI major homozygote genotype had significantly lower results on a 10-word delayed recall test (p = 0.044) and verbal fluency test (p = 0.013), and individuals with the TaqI major homozygote genotype had significantly lower results on a verbal fluency test (p = 0.030) compared to individuals with the corresponding minor homozygote genotype.

CONCLUSION

Patients with positive AD core biomarkers have low CSF levels of 25(OH)D, despite sufficient serum levels. CSF levels of 25(OH)D do not seem to be affected by any of the four VDR gene polymorphisms. TaqI and BsmI major homozygote genotypes might be at increased risk for development of cognitive decline.

Gut Microbiota and Fecal Metabolites Associated With Neurocognitive Impairment in HIV-Infected Population

Gut microbiota dysbiosis has been associated with many neurological diseases. However, how microbiota composition and metabolism relate to neurocognitive impairment (NCI) in HIV-infected individuals is largely unknown. In this study, a total of 102 HIV infected participants were classified into two groups—those with NCI and those without—using the global deficit score (GDS). Fecal samples were collected from the participants for 16S rRNA gene sequencing and untargeted metabolomics. The plasma level of 25 hydroxy-vitamin D (25(OH)D) was also evaluated. Although α-diversity and β-diversity were comparable, the HIV patients with NCI were significantly different from those without NCI in terms of abundance of several gut microbiota. The decreased abundance of butyrate-producing bacteria (BPB) and increased abundance of Klebsiella were related with NCI and carotid intima-media thickness (CIMT). Significant differences in fecal metabolites were also found between individuals with versus without NCI, including increased bile acids and bioactive lipids, decreased vitamin D, terpenoids, and resolvin D1 in the NCI group. Furthermore, the perturbed metabolic profile was closely related to BPB and Klebsiella. In addition, a low level of vitamin D was associated with NCI and CIMT. Both fecal and plasma vitamin D were positively correlated with BPB. Our results show that BPB and Klebsiella and the associated metabolites are associated with NCI in people with HIV. In addition, vitamin D, both in feces and blood, was associated with NCI and BPB, suggesting a protective effect of vitamin D on NCI.

Vitamin D Levels, APOE Allele, and MRI Volumetry Assessed by NeuroQuant in Norwegian Adults with Cognitive Symptoms

BACKGROUND

Allele ɛ4 of the apolipoprotein (APOE∈4) gene is the strongest known genetic risk factor for late-onset sporadic Alzheimer's disease. A possible relationship between vitamin D and APOE is not yet clear.

OBJECTIVE

In this exploratory, cross-sectional study, we examined the association between serum levels of 25-hydroxyvitamin D [25(OH)D] and brain volumes and the associations of both serum levels of 25(OH)D and APOE polymorphism to brain volumes in 127 persons (mean age 66 years) with cognitive symptoms.

METHODS

All subjects were examined with fully automated software for MRI volumetry, NeuroQuant.

RESULTS

After adjustment for relevant covariates, higher serum 25(OH)D levels were associated with greater volumes of cortical gray matter on both left (p = 0.02) and right (p = 0.04) sides. When both 25(OH)D levels and APOE genotype were used as the main covariates, no significant associations were found between vitamin D level and brain volume in any of the 11 brain regions. In adjusted models, only homozygous but not heterozygous APOE∈4 allele carriers had significantly larger inferior lateral ventricles (p = 0.003) and smaller hippocampal volume (p = 0.035) than those without ɛ4. Homozygous APOE∈4 carriers also had significantly higher vitamin D levels (p = 0.009) compared to persons without the APOE∈4 allele.

CONCLUSION

Higher vitamin D levels might have a preserving effect on cortical grey matter volume.