Dataset Information

Vitamin D, cognition, and dementia: a systematic review and meta-analysis.

ABSTRACT:

Objective

To examine the association between cognitive function and dementia with vitamin D concentration in adults.

Methods

Five databases were searched for English-language studies up to August 2010, and included all study designs with a comparative group. Cognitive function or impairment was defined by tests of global or domain-specific cognitive performance and dementia was diagnosed according to recognized criteria. A vitamin D measurement was required. Two authors independently extracted data and assessed study quality using predefined criteria. The Q statistic and I² methods were used to test for heterogeneity. We conducted meta-analyses using random effects models for the weighted mean difference (WMD) and Hedge's g.

Results

Thirty-seven studies were included; 8 contained data allowing mean Mini-Mental State Examination (MMSE) scores to be compared between participants with vitamin D <50 nmol/L to those with values ?50 nmol/L. There was significant heterogeneity among the studies that compared the WMD for MMSE but an overall positive effect for the higher vitamin D group (1.2, 95% confidence interval [CI] 0.5 to 1.9; I² = 0.65; p = 0.002). The small positive effect persisted despite several sensitivity analyses. Six studies presented data comparing Alzheimer disease (AD) to controls but 2 utilized a method withdrawn from commercial use. For the remaining 4 studies the AD group had a lower vitamin D concentration compared to the control group (WMD = -6.2 nmol/L, 95% CI -10.6 to -1.8) with no heterogeneity (I² < 0.01; p = 0.53).

Conclusion

These results suggest that lower vitamin D concentrations are associated with poorer cognitive function and a higher risk of AD. Further studies are required to determine the significance and potential public health benefit of this association.

SUBMITTER: Balion C

PROVIDER: S-EPMC3448747 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature

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Publications

Vitamin D, cognition, and dementia: a systematic review and meta-analysis.

Balion Cynthia C Griffith Lauren E LE Strifler Lisa L Henderson Matthew M Patterson Christopher C Heckman George G Llewellyn David J DJ Raina Parminder P

Neurology 20120901 13

<h4>Objective</h4>To examine the association between cognitive function and dementia with vitamin D concentration in adults.<h4>Methods</h4>Five databases were searched for English-language studies up to August 2010, and included all study designs with a comparative group. Cognitive function or impairment was defined by tests of global or domain-specific cognitive performance and dementia was diagnosed according to recognized criteria. A vitamin D measurement was required. Two authors independen ...[more]

PMID: 23008220

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Project description:In 2012, the United States Food and Drug Administration (FDA) issued a warning regarding potential adverse effects of HMG-CoA reductase inhibitors (statins) on cognition, based on the Adverse Events Reporting System and a review of the medical literature. We aimed to synthesize randomized clinical trial (RCTs) evidence on the association between statin therapy and cognitive outcomes.We searched MEDLINE, EMBASE, and Cochrane CENTRAL through December 2012, and reviewed published systematic reviews of statin treatment. We sought RCTs that compared statin treatment versus placebo or standard care, and reported at least one cognitive outcome (frequency of adverse cognitive events or measurements using standard neuropsychological cognitive test scores). Studies reporting sufficient information to calculate effect sizes were included in meta-analyses. Standardized and unstandardized mean differences were calculated for continuous outcomes for global cognition and for pre-specified cognitive domains. The main outcome was change in cognition measured by neuropsychological tests; an outcome of secondary interest was the frequency of adverse cognitive events observed during follow-up.We identified 25 RCTs (all placebo-controlled) reporting cognitive outcomes in 46,836 subjects, of which 23 RCTs reported cognitive test results in 29,012 participants. Adverse cognitive outcomes attributable to statins were rarely reported in trials involving cognitively normal or impaired subjects. Furthermore, meta-analysis of cognitive test data (14 studies; 27,643 participants) failed to show significant adverse effects of statins on all tests of cognition in either cognitively normal subjects (standardized mean difference 0.01, 95% confidence interval, CI, -0.01 to 0.03, p?=?0.42) or Alzheimer's disease subjects (standardized mean difference -0.05, 95% CI -0.19 to 0.10, p?=?0.38).Statin therapy was not associated with cognitive impairment in RCTs. These results raise questions regarding the continued merit of the FDA warning about potential adverse effects of statins on cognition.

Dataset Information

Vitamin D, cognition, and dementia: a systematic review and meta-analysis.

Objective

Methods

Results

Conclusion

Publications

Vitamin D, cognition, and dementia: a systematic review and meta-analysis.

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