Habitual dietary nitrate intake and cognition in the Australian Imaging, Biomarkers and Lifestyle Study of ageing: A prospective cohort study.

BACKGROUND & AIMS: Dietary nitrate improves cardiovascular health via a nitric oxide (NO) pathway. NO is key to both cardiovascular and brain health. There is also a strong association between vascular risk factors and brain health. Dietary nitrate intake could therefore be associated with better cognitive function and reduced risk of cognitive decline. This is yet to be investigated. The aim of this study was to investigate the association between habitual intake of dietary nitrate from sources where nitrate is naturally present, and cognitive function, and cognitive decline, in the presence or absence of the apolipoprotein E (APOE) ε4 allele. METHODS: The study included 1254 older adult participants of the Australian Imaging, Biomarkers and Lifestyle Study of Ageing who were cognitively normal at baseline. Plant-derived, vegetable-derived, animal derived nitrate (not including meat where nitrate is an allowed additive), and total nitrate intakes were calculated from baseline food frequency questionnaires using comprehensive nitrate databases. Cognition was assessed at baseline and every 18 months over a follow-up period of 126 months using a comprehensive neuropsychological test battery. Multivariable-adjusted linear mixed effect models were used to examine the association between baseline nitrate intake and cognition over the 126 months (median [IQR] follow-up time of 36 [18-72] months), stratified by APOE ε4 carrier status. RESULTS: In non APOE ε4 carriers, for every 60 mg/day higher intake of plant-derived nitrate at baseline there was an associated higher language score [ß (95% CI): 0.10 (0.01, 0.19)] over 126 months, after multivariable adjustments. In APOE ε4 carriers, there was an associated better episodic recall memory [0.24 (0.08, 0.41)] and recognition memory [0.15 (0.01, 0.30)] scores. Similar associations were seen for the intakes of vegetable-derived and total nitrate. Additionally, in APOE ε4 carriers, for every 6 mg/day higher intake of animal-derived nitrate (excluding meat with nitrate as an allowed additive) at baseline there was an associated higher executive function score [ß (95% CI): 1.41 (0.42, 2.39)]. We did not find any evidence of an association between dietary nitrate intake and rate of cognitive decline. CONCLUSION: Our results suggest that habitual intake of dietary nitrate from sources where nitrate is naturally present impacts cognitive performance in an APOE genotype contingent manner. Further work is needed to validate our findings and understand potential mechanisms underlying the observed effects.

Potential role of dietary nitrate in relation to cardiovascular and cerebrovascular health, cognition, cognitive decline and dementia: a review.

There is currently no effective treatment for dementia, of which Alzheimer's disease (AD) is the most common form. It is, therefore, imperative to focus on evidence-based preventive strategies to combat this extremely debilitating chronic disease. Nitric oxide (NO) is a key signalling molecule in the cardiovascular, cerebrovascular, and central nervous systems. Vegetables rich in nitrate, such as spinach and beetroot, are an important source of NO, with beneficial effects on validated markers of cardiovascular health and an association with a lower risk of cardiovascular disease. Given the link between cardiovascular disease risk factors and dementia, together with the important role of NO in vascular health and cognition, it is important to determine whether dietary nitrate could also improve cognitive function, markers of brain health, and lower risk of dementia. This review presents an overview of NO's role in the cardiovascular, cerebrovascular, and central nervous systems; an overview of the available evidence that nitrate, through effects on NO, improves cardiovascular health; and evaluates the current evidence regarding dietary nitrate's potential role in cerebrovascular health, cognitive function, and brain health assessed via biomarkers.

The Effect of Silver Diamine Fluoride in Preventing Caries in the Primary Dentition: A Systematic Review and Meta-Analysis.

OBJECTIVES: To investigate whether silver diamine fluoride (SDF) is effective in preventing new caries lesions in primary teeth when compared to placebo or active treatments. METHODS: Systematic review (CRD42016036963) of controlled clinical trials. Searches were performed in 9 electronic databases, 5 registers of ongoing trials, and reference lists of identified review articles. Two researchers carried out data extraction and quality appraisal independently. The primary outcome was the difference in caries increment (decayed, missing, and filled surfaces or teeth - dmfs or dmft) between SDF and control groups. These differences were pooled as weighted mean differences (WMD) and prevented fractions (PF). RESULTS: Searches yielded 2,366 unique records; 6 reports of 4 trials that randomized 1,118 and analyzed 915 participants were included. Two trials compared SDF to no treatment, 1 compared SDF to placebo and sodium fluoride varnish (FV), and 1 compared SDF to high-viscosity glass ionomer cement (GIC). All studies had at least 1 domain with unclear or high risk of bias. After 24 months of follow-up, in comparison to placebo, no treatment, and FV, SDF applications significantly reduced the development of new dentin caries lesions (placebo or no treatment: WMD = -1.15, PF = 77.5%; FV: WMD = -0.43, PF = 54.0%). GIC was more effective than SDF after 12 months of follow-up but the difference between them was not statistically significant (WMD, dmft: 0.34, PF: -6.09%). CONCLUSION: When applied to caries lesions in primary teeth, SDF compared to no treatment, placebo or FV appears to effectively prevent dental caries in the entire dentition. However, trials specifically designed to assess this outcome are needed.

Controlling caries in exposed root surfaces with silver diamine fluoride: A systematic review with meta-analysis.

BACKGROUND: In this systematic review, the authors aim to assess the effect of silver diamine fluoride (SDF) in preventing and arresting caries in exposed root surfaces of adults. TYPES OF STUDIES REVIEWED: Two reviewers independently searched for controlled clinical trials with at least 12 months of follow-up, without language or date of publication restraints, in 8 electronic databases, 5 registries of ongoing trials, and reference lists of narrative reviews. RESULTS: The authors found 2,356 unique records and included 3 trials in which the investigators randomly assigned 895 older adults. Investigators in all studies compared SDF with placebo; investigators in 1 also compared 38% SDF with chlorhexidine and sodium fluoride varnishes. The primary effect measures were the weighted mean differences (WMDs) in decayed or filled root surfaces (DFRS) and the mean differences in arrested carious lesions between SDF and control groups. The studies had low risk of bias in most domains. SDF applications had a significantly better preventive effect in comparison with placebo (WMD DFRS: 24 months, -0.56; 95% confidence interval, -0.77 to -0.36; 30 months or more, -0.80; 95% confidence interval, -1.19 to -0.42), and they were as effective as either chlorhexidine or sodium fluoride varnish in preventing new root carious lesions. SDF also provided a significantly higher caries arrest effect than did placebo (pooled results not calculated). Complaints about black staining of the carious lesions by SDF were rare among older adults. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Yearly 38% SDF applications to exposed root surfaces of older adults are a simple, inexpensive, and effective way of preventing caries initiation and progression.

Antibiotics in aggressive periodontitis, is there a clinical benefit?

Data sourcesMedline, Embase and CENTRAL databases were searched up to December 2014. Unpublished data were sought by searching a database listing unpublished studies OpenGray [http://www.opengrey.eu/], formerly OpenSIGLE.Study selectionRandomised clinical trials assessing treatment of patients with AgP comparing scaling and root planing (SRP) alone with SRP plus a single antibiotic or a combination of drugs with a minimum of three months follow-up were considered. Studies specifically designed to evaluate smokers or subjects with diabetes mellitus and HIV/AIDS were not included.Data extraction and synthesisTwo researchers independently screened titles, abstracts and full texts of the search results. The studies, which fulfilled inclusion criteria, underwent validity assessment and data extraction using a specifically designed form. The quality of included studies was assessed using the Cochranes collaboration tool for risk of bias. Only two of the 11 included trials were considered at a low risk of bias. The data extracted from ten studies was analysed by pair-wise meta-analyses and the data extracted from five studies was included in Bayesian network meta-analyses pooled estimates. The six studies evaluated in the pairwise meta-analyses were excluded in the pooled estimates because four studies included patients with advanced disease only and one study did not present average data for pocket depth (PD) and clinical attachment level (CAL) and another one for using a different mechanical treatment.ResultsFourteen studies reporting 11 randomised clinical trials with a total of 388 patients were included in the review. Nine of 11 studies reported a statistically significant greater gain in full mouth mean clinical attachment (CA) and reduction in probing depth (PD) when a systemic antibiotic was used. From those studies the calculated mean difference for CA gained was 1.08 mm (p < 0.0001) and for PD reduction was 1.05 mm (p< 0.00001) for SRP + Metronidazole (Mtz). For SRP + Mtz+ amoxicillin (Amx) group the mean difference was 0.45 mm for CA gained and 0.53 mm for PD reduction (p<0.00001) than SRP alone/placebo. Bayesian network meta-analysis showed some additional benefits in CA gain and PD reduction when SRP was associated with systemic antibiotics.ConclusionsThe results support a statistically significant benefit of adjunctive systemic antibiotics in the treatment of AgP. The most consistent advantages - reduction in PD and CAL gain - were attained with the use of Mtz and Mtz + Amx. Future RCTs should be designed in order to directly compare these two antibiotic protocols in the treatment of AgP.