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Vitamin D deficiency as a risk factor for dementia and Alzheimer's disease: an updated meta-analysis.
Chai, B, Gao, F, Wu, R, Dong, T, Gu, C, Lin, Q, Zhang, Y
BMC neurology. 2019;(1):284
Abstract
BACKGROUND We aimed to comprehensively explore the associations between serum 25(OH)D deficiency and risk of dementia and Alzheimer's disease(AD). METHODS We systematically searched Pubmed, the Cochrane Library, Embase and the reference lists of pertinent review articles for relevant articles published from database inception up until January 2019. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with random effects models using the Stata 12.0 statistical software package. RESULTS Twelve prospective cohort studies and four cross-sectional studies were included in this meta-analysis. The pooled HRs of dementia and AD, respectively, were 1.32 (95%CI: 1.16, 1.52) and 1.34 (95%CI: 1.13, 1.60) for vitamin D deficiency (< 20 ng/ml). In the subgroup analyses, the pooled HRs of dementia and AD, respectively, were 1.48 (95%CI: 1.19, 1.85) and 1.51 (95%CI: 1.04, 2.18) for moderate vitamin D deficiency (10-20 ng/ml) and 1.20 (95%CI: 0.99, 1.44) and 1.36 (95%CI: 1.01, 1.84) for severe vitamin D deficiency (< 10 ng/ml). CONCLUSION There are significant associations between vitamin D deficiency and both dementia and AD. There are stronger associations between severe vitamin D deficiency (< 10 ng/ml) and both dementia and AD compared to moderate vitamin D deficiency (10-20 ng/ml).
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Vitamin D status and mortality risk among patients on dialysis: a systematic review and meta-analysis of observational studies.
Zhang, Y, Darssan, D, Pascoe, EM, Johnson, DW, Pi, H, Dong, J
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2018;(10):1742-1751
Abstract
BACKGROUND Vitamin D deficiency is highly prevalent in patients on dialysis. Although vitamin D deficiency is closely associated with cardiovascular disease (CVD) and high mortality in the general population, the relationship between serum 25-hydroxyvitamin D [25(OH)D] and all-cause and cardiovascular mortality in dialysis patients is uncertain. We aim to explore the relationship between serum 25(OH)D levels and all-cause and cardiovascular mortality in dialysis patients. METHODS This is a systematic review and meta-analysis of clinical studies among patients receiving maintenance dialysis. We did a systematic literature search in PubMed and Embase to identify studies reporting the relationship between serum 25(OH)D levels and all-cause and cardiovascular mortality in patients on dialysis. The search was last updated on 10 February 2017. RESULTS The study included 18 moderate to high-quality cohort studies with an overall sample of 14 154 patients on dialysis. The relative risk of all-cause mortality per 10 ng/mL increase in serum 25(OH)D level was 0.78 [95% confidence interval (CI) 0.71-0.86], although there was marked heterogeneity (I2=96%, P < 0.01) that was partly explained by differences in CVD prevalence, baseline parathyroid hormone level and dialysis duration among included studies. The relative risk of cardiovascular mortality per 10 ng/mL increase in serum 25(OH)D level was 0.71 (95% CI 0.63-0.79), with substantial heterogeneity (I2=74%, P=0.004) that was largely explained by differences in study type and serum 25(OH)D measurement method. CONCLUSIONS In the present study, increased serum 25(OH)D level was significantly associated with lower all-cause mortality and lower cardiovascular mortality in dialysis patients.
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Serum vitamin D level and vitamin D receptor genotypes may be associated with tuberculosis clinical characteristics: A case-control study.
Zhang, Y, Zhu, H, Yang, X, Guo, S, Liang, Q, Lu, Y, Chen, X
Medicine. 2018;(30):e11732
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Abstract
Vitamin D is associated with the susceptibility of tuberculosis and might have an adjunctive effect on anti-tuberculosis treatment. This study aims to investigate the association of vitamin D deficiency and vitamin D receptor (VDR) gene polymorphisms with susceptibility and severity to multidrug-resistant tuberculosis (MDR-TB) in comparison with drug-sensitive tuberculosis (DS-TB) and health controls in China.A total of 180 patients with pulmonary TB (128 DS-TB, 52 MDR-TB) and 59 healthy controls were enrolled into 3 groups. Vitamin D levels and VDR genotypes at FokI, BsmI, ApaI, and TaqI sites of all the participants and clinical characteristics of patients with TB were measured and collected.Statistical analysis revealed that vitamin D levels were lower in both TB groups. Patients with TB with bilateral lesions and patients with MDR-TB with extrapulmonary TB had lower vitamin D levels. The frequencies of ff genotype and f allele were higher in both TB groups. Patients with Ff genotype and ff genotype had lower proportion of extrapulmonary TB. Patients with ff genotype had higher proportion of retreatment. Male patients with ff genotype had higher proportion of cavity formation. Patients with DS-TB with AA genotype had higher proportion of cavity formation.Our findings demonstrate that vitamin D deficiency and ff genotype may be the risk factors of TB in Chinese population. In addition, patients with TB with lower level of vitamin D may have a greater risk of bilateral lesions and extrapulmonary TB. VDR genotypes may be associated with TB clinical characteristics.
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Preoperative vitamin D deficiency increases the risk of postoperative cognitive dysfunction: a predefined exploratory sub-analysis.
Zhang, Y, Shan, GJ, Zhang, YX, Cao, SJ, Zhu, SN, Li, HJ, Ma, D, Wang, DX, ,
Acta anaesthesiologica Scandinavica. 2018;(7):924-935
Abstract
BACKGROUND Vitamin D is important for maintaining physiological functions including cognition and its deficiency is associated with the occurrence of cognitive impairment. This study was to explore the association between preoperative vitamin D status and the occurrence of postoperative cognitive dysfunction (POCD) in elderly patients undergoing major surgery. METHODS This was a predefined exploratory sub-analysis of one-centre data from a randomized controlled trial. In all, 123 elderly (≥ 65 years) patients who were scheduled to undergo major cancer surgery were recruited. Serum 25-hydroxyvitamin D concentration was measured before surgery. In total, 59 nonsurgical control subjects with comparable age and education level were also enrolled. A battery of neuropsychological tests was administered the day before and the 7th day after surgery in patients or at the same time interval in control subjects. POCD was diagnosed according to the ISPOCD1 definition. RESULTS 71.5% (88/123) of elderly patients had vitamin D deficiency (serum 25-hydroxyvitamin D concentration < 12 ng/ml) before surgery; 24.4% (30/123) of them developed cognitive dysfunction at 1 week after surgery. After adjusting for confounding factors, high preoperative serum 25-hydroxyvitamine D concentration was related to a decreased risk of POCD (odds ratio [OR]: 0.829, 95% confidence interval [CI]: 0.708-0.971; P = 0.020), whereas preoperative vitamin D deficiency was associated with an increased risk of POCD (OR: 8.427, 95% CI: 1.595-44.511; P = 0.012). CONCLUSIONS Vitamin D deficiency is prevalent in elderly patients undergoing major cancer surgery and increases the risk of early POCD development. Whether prophylactic vitamin D supplementation can reduce POCD in the elderly deserves further study.
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Decreased serum vitamin D levels in children with asthma are associated with increased corticosteroid use.
Searing, DA, Zhang, Y, Murphy, JR, Hauk, PJ, Goleva, E, Leung, DY
The Journal of allergy and clinical immunology. 2010;(5):995-1000
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BACKGROUND There is little knowledge about clinical variables associated with vitamin D (VitD) insufficiency in asthmatic children. OBJECTIVE We sought to investigate disease variables associated with VitD insufficiency in patients with childhood asthma and interaction of VitD with corticosteroid-mediated anti-inflammatory responses. METHODS We analyzed 25-hydroxyvitamin D serum levels in 100 asthmatic children to investigate relationships between 25-hydroxyvitamin D levels and patients' characteristics. We determined VitD's effects on dexamethasone (DEX) induction of mitogen-activated protein kinase phosphatase 1 and IL-10 in PBMCs. RESULTS The median 25-hydroxyvitamin D serum level was 31 ng/mL. Forty-seven percent of subjects had VitD levels in the insufficient range (<30 ng/mL), whereas 17% were VitD deficient (<20 ng/mL). Log(10) IgE (P = .01, rho = -0.25) and the number of positive aeroallergen skin prick test responses (P = .02, rho = -0.23) showed a significant inverse correlation with VitD levels, whereas FEV(1) percent predicted (P = .004, rho = 0.34) and FEV(1)/forced vital capacity ratio (P = .01, rho = 0.30) showed a significant positive correlation with VitD levels. The use of inhaled steroids (P = .0475), use of oral steroids (P = .02), and total steroid dose (P = .001) all showed significant inverse correlations with VitD levels. The amount of mitogen-activated protein kinase phosphatase 1 and IL10 mRNA induced by VitD plus DEX was significantly greater than that induced by DEX alone (P < .01). In an experimental model of steroid resistance in which DEX alone did not inhibit T-cell proliferation, addition of VitD to DEX resulted in significant dose-dependent suppression of cell proliferation. CONCLUSIONS Corticosteroid use and worsening airflow limitation are associated with lower VitD serum levels in asthmatic patients. VitD enhances glucocorticoid action in PBMCs from asthmatic patients and enhances the immunosuppressive function of DEX in vitro.