Quality assessment of systematic reviews of vitamin D, cognition and dementia

Aghajafari, Fariba; Pond, Dimity; Catzikiris, Nigel; Cameron, Ian D.

doi:10.1192/bjo.2018.32

Cited by 13 publications

(14 citation statements)

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“…Previous meta-analyses have shown that the measures used to assess the relationship between vitamin D and dementia are relatively simple. This may create a bias in the literature as the measures used in the published literature cover less than 30% of the available neuropsychological tests [38]. When all neuropsychological tests were included, despite the increased heterogeneity, we found a significant association between vitamin D deficiency and dementia.…”

Section: Discussionmentioning

confidence: 83%

Vitamin D deficiency as a risk factor for dementia and Alzheimer’s disease: an updated meta-analysis

et al. 2019

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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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Section: Discussionmentioning

confidence: 83%

Vitamin D deficiency as a risk factor for dementia and Alzheimer’s disease: an updated meta-analysis

et al. 2019

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“…(10) Such conflicting results are probably explained by the quality of available evidence, which in general is not optimal. (37) Vitamin D deficiency or insufficiency are associated with a number of chronic conditions that can precipitate the progression of cognitive decline. (13) Therefore it is plausible that the potential cognitive benefits of vitamin D identified in observational studies may be mediated by improvements in accompanying chronic diseases.…”

Section: Discussionmentioning

confidence: 99%

Cognitive function and vitamin B12 and D in elders from Ecuador

Veloz

Carpio-Arias

Vargas³

et al. 2021

Preprint

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IntroductionCurrent evidence still does not support the role of vitamin B12 or vitamin D in age-associated cognitive impairment.ObjectiveEvaluate the association between vitamin B12 and D and cognitive function in elders.MethodologySample included 1733 individuals 60 years old and older, who participated in the SABE study that was carried out in Ecuador. Cognitive function was measured using abbreviated version of minimental state examination (MMSE). Vitamin B12 and D were measured in blood. Data were analyzed through linear regression models with restricted cubic splines (RCSs). Models were adjusted by sex, years of education, region (urban highland, urban coast, rural highlands, rural coast), socioeconomic status, and ethnicity.ResultsIndependently from sex, age, years of education, ethnicity, socioeconomic status and geographical zone of residence, we found that vitamin B12 but not vitamin D levels were associated with cognitive function in a representative group of Ecuadorian elders. Elders with lower levels of vitamin B12 showed lower MMSE scores in comparison to elders with higher levels of vitamin B12. Moreover, a statically significant non linear interaction was found between vitamin B12 and age with respect to cognitive function. In this way, we observed that in elders 75 years old and older whose levels of vitamin B12 were 271 pg/ml or less, the drop of cognitive function was particularly steep in comparison to elders whose levels of vitamin B12 were 647 pg/ml or more.ConclusionsLow levels of vitamin B12 but not of vitamin D are associated with low cognitive functioning.

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“…An adequate vitamin D level is necessary to preserve neurological function development and protect the adult brain [15]. Multiple studies have shown a correlation between vitamin D level and cognitive function decline in elderly persons, with an effect on brain health and memory [14,[36][37][38][39][40], but few studies have evaluated this effect in children. Nassar et al [41] stated that the vitamin D level was significantly lower in children with delayed school achievement, with a positive correlation between vitamin D level and Wechsler Intelligence Scale values for Children.…”

Section: Discussionmentioning

confidence: 99%

Effect of circulating 25-hydroxyvitamin D and antioxidant capacity level on cognitive function parameters of children with idiopathic short stature

Ahmed

Sakhr

Ali

et al. 2020

Egypt Pediatric Association Gaz

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Background: An optimal level of vitamin D is necessary for normal bone growth. Recently, vitamin D has been linked to many neurological disorders, changes in antioxidant capacity levels, and cognitive function decline in old age; thus, the aim was to evaluate the effect of vitamin D and antioxidant levels on the cognitive function parameters of children with idiopathic short stature (ISS). Results: A prospective case-control study was conducted with 60 primary school-aged children with ISS who were compared to 60 unrelated healthy age-and sex-matched children as a control group. A complete clinical evaluation; anthropometric measurements; neurocognitive function parameters using the Stanford-Binet test, fifth edition; vitamin D level; total antioxidant capacity (TAC); total oxidative stress (TOS); and oxidative stress index (OSI) were measured. A total of 83.3% of children with ISS had a vitamin D level < 30 ng/ml with significantly lower vitamin D levels than the control group. The TAC level was significantly lower in children with ISS than in healthy children. Children with ISS had an average level for all of the cognitive function parameters but a lower non-verbal IQ, full-scale IQ, fluid reasoning, knowledge, quantitative reasoning, and working memory than healthy controls. A positive correlation was found between vitamin D level and all anthropometric measurements, all IQ parameters, and TAC levels in the studied children. A positive correlation was found between TAC and all IQ parameters. Conclusion: Vitamin D level and antioxidant capacity level have a major impact on cognitive function parameters in children with ISS.

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Quality assessment of systematic reviews of vitamin D, cognition and dementia

Cited by 13 publications

References 50 publications

Vitamin D deficiency as a risk factor for dementia and Alzheimer’s disease: an updated meta-analysis

Vitamin D deficiency as a risk factor for dementia and Alzheimer’s disease: an updated meta-analysis

Cognitive function and vitamin B12 and D in elders from Ecuador

Effect of circulating 25-hydroxyvitamin D and antioxidant capacity level on cognitive function parameters of children with idiopathic short stature

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