Protocol for a systematic review assessing the measurement of dietary sodium intake among adults with elevated blood pressure

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420Introduction Accurate sodium intake estimates in adults with elevated blood pressure are essential for monitoring salt reduction progress and preventing cardiovascular diseases. However, sodium assessments are challenging in this high-risk population because many commonly used antihypertensive drugs alter urinary sodium excretion. Despite the high cost and substantial participant burden of gold-standard 24-hour urine collection, the relative performance of existing spot-urine based equations and dietary self-report instruments have not been well studied in this population, who will benefit from salt restriction. This systematic review aims to describe the current methods of assessing dietary sodium intake in adults with elevated blood pressure and determine what method can provide a valid and accurate estimate of sodium intake compared with the gold standard 24-hour urine collection. Methods and analysis Studies assessing sodium intake in adults aged 18 years and above with reported elevated blood pressure will be included. Five electronic databases (MEDLINE, Embase, Global Health, WoS and Cochrane CENTRAL) will be systematically searched from inception to March 2021. Also, a manual search of bibliographies and grey literature will be conducted. Two reviewers will screen the records independently for eligibility. One reviewer will extract all data, and two others will review the extracted data for accuracy. The methodological quality of included studies will be evaluated based on three scoring systems: (1) National Heart, Lung and Blood Institute for interventional studies; (2) Biomarker-based Cross-sectional Studies for biomarker-based observational studies and (3) European Micronutrient Recommendation Aligned Network of Excellence for validation studies of dietary self-report instruments. Ethics and dissemination As the proposed systematic review will collect and analyse secondary data associated with individuals, there will be no ethical approval requirement. Findings will be disseminated in a peer-reviewed journal or presented at a conference.http://dx.doi.org/10.1136/bmjopen-2021-05217512pubpub

The economic burden of dementia in low- and middle-income countries (LMICs): a systematic review

Introduction More than two-thirds of people with dementia live in low- and middle-income countries (LMICs), resulting in a significant economic burden in these settings. In this systematic review, we consolidate the existing evidence on the cost of dementia in LMICs. Methods Six databases were searched for original research reporting on the costs associated with all-cause dementia or its subtypes in LMICs. The national-level dementia costs inflated to 2019 were expressed as percentages of each country’s gross domestic product (GDP) and summarised as the total mean percentage of GDP. The risk of bias of studies was assessed using the Larg and Moss method. Results We identified 14 095 articles, of which 24 studies met the eligibility criteria. Most studies had a low risk of bias. Of the 138 LMICs, data were available from 122 countries. The total annual absolute per capita cost ranged from US$590.78 for mild dementia to US$25 510.66 for severe dementia. Costs increased with the severity of dementia and the number of comorbidities. The estimated annual total national costs of dementia ranged from US$1.04 million in Vanuatu to US$195 billion in China. The average total national expenditure on dementia estimated as a proportion of GDP in LMICs was 0.45%. Indirect costs, on average, accounted for 58% of the total cost of dementia, while direct costs contributed 42%. Lack of nationally representative samples, variation in cost components, and quantification of indirect cost were the major methodological challenges identified in the existing studies. Conclusion The estimated costs of dementia in LMICs are lower than in high-income countries. Indirect costs contribute the most to the LMIC cost. Early detection of dementia and management of comorbidities is essential for reducing costs. The current costs are likely to be an underestimation due to limited dementia costing studies conducted in LMICs, especially in countries defined as low- income. PROSPERO registration number The protocol was registered in the International Prospective Register of Systematic Reviews database with registration number CRD42020191321.http://dx.doi.org/10.1136/bmjgh-2021-0074097pubpub

Link Between Dietary Sodium Intake, Cognitive Function, and Dementia Risk in Middle-Aged and Older Adults: A Systematic Review

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420Background: A key focus for dementia risk-reduction is the prevention of socio-demographic, lifestyle, and nutritional risk factors. High sodium intake is associated with hypertension and cardiovascular disease (both are linked to dementia), generating numerous recommendations for salt reduction to improve cardiovascular health. Objective: This systematic review aimed to assess, in middle- and older-aged people, the relationship between dietary sodium intake and cognitive outcomes including cognitive function, risk of cognitive decline, or dementia. Methods: Six databases (PubMed, EMBASE, CINAHL, Psych info, Web of Science, and Cochrane Library) were searched from inception to 1 March 2020. Data extraction included information on study design, population characteristics, sodium reduction strategy (trials) or assessment of dietary sodium intake (observational studies), measurement of cognitive function or dementia, and summary of main results. Risk-of-bias assessments were performed using the National Heart, Lung, and Blood Institute (NHLBI) assessment tool. Results: Fifteen studies met the inclusion criteria including one clinical trial, six cohorts, and eight cross-sectional studies. Studies reported mixed associations between sodium levels and cognition. Results from the only clinical trial showed that a lower sodium intake was associated with improved cognition over six months. In analysis restricted to only high-quality studies, three out of four studies found that higher sodium intake was associated with impaired cognitive function. Conclusion: There is some evidence that high salt intake is associated with poor cognition. However, findings are mixed, likely due to poor methodological quality, and heterogeneous dietary, analytical, and cognitive assessment methods and design of the studies. Reduced sodium intake may be a potential target for intervention. High quality prospective studies and clinical trials are needed.https://doi.org/10.3233/JAD-19133976pubpub

Nutritional interventions for the prevention of cognitive impairment and dementia in developing economies in East-Asia: a systematic review and meta-analysis

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420Dementia represents a key impending global health challenge. The aim of this systematic review was to evaluate the current evidence on nutritional interventions for the prevention of dementia in developing economies in East-Asia. Four comprehensive databases were searched from inception until January 2020: MEDLINE, Embase, PsycInfo, and Scopus. The search was restricted to randomized controlled trials [RCTs] in adult humans, assessing the effect of nutritional interventions on global and domain specific cognitive performance and dementia risk. Meta-analysis of data was conducted for each domain and sub-categorized according to the type of nutritional intervention. Twenty-four RCTs were included, of which, fifteen studies showed significant beneficial effects on cognition. Eighteen studies were included in the meta-analysis. Significant beneficial effects were found for essential fatty acids (EPA/DHA) and micronutrient supplementation on specific cognitive domains including attention and orientation, perception, verbal functions and language skills. The effect size of the interventions appeared to be greater in older subjects with cognitive impairment. Supplementation with B-vitamins and essential fatty acids may represent promising strategies to minimize age-related cognitive decline in Asian populations. Large, high-quality, long-term trials are needed to confirm these findings.This research was funded by the National Institute for Health Research (NIHR) (16/137/62 - Dementia Prevention and Enhanced Care (DePEC), Newcastle University, United Kingdom), using UK aid from the UK Government to support global health research. The views expressed in this publication are those of the author(s) and not necessarily those of the NIHR or the UK Department of Health and Social Care.https://doi.org/10.1080/10408398.2020.184878562pubpub

Feasibility and acceptability of a dietary intervention study to reduce salt intake and increase high-nitrate vegetable consumption among middle-aged and older Malaysian adults with elevated blood pressure: a study protocol

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420Introduction Global population ageing is one of the key factors linked to the projected rise of dementia incidence. Hence, there is a clear need to identify strategies to overcome this expected health burden and have a meaningful impact on populations’ health worldwide. Current evidence supports the role of modifiable dietary and lifestyle risk factors in reducing the risk of dementia. In South-East Asia, changes in eating and lifestyle patterns under the influence of westernised habits have resulted in significant increases in the prevalence of metabolic, cardiovascular and neurodegenerative non-communicable diseases (NCDs). Low vegetable consumption and high sodium intake have been identified as key contributors to the increased prevalence of NCDs in these countries. Therefore, nutritional and lifestyle strategies targeting these dietary risk factors are warranted. The overall objective of this randomised feasibility trial is to demonstrate the acceptability of a dietary intervention to increase the consumption of high-nitrate green leafy vegetables and reduce salt intake over 6 months among Malaysian adults with raised blood pressure. Methods and analysis Primary outcomes focus on feasibility measures of recruitment, retention, implementation and acceptability of the intervention. Secondary outcomes will include blood pressure, cognitive function, body composition and physical function (including muscle strength and gait speed). Adherence to the dietary intervention will be assessed through collection of biological samples, 24-hour recall and Food Frequency Questionnaire. A subgroup of participants will also complete postintervention focus groups to further explore the feasibility considerations of executing a larger trial, the ability of these individuals to make dietary changes and the barriers and facilitators associated with implementing these changes.http://dx.doi.org/10.1136/bmjopen-2019-03545310pubpub

Risk of conversion from mild cognitive impairment to dementia in low- and middle-income countries: A systematic review and meta-analysis

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420Introduction With no treatment for dementia, there is a need to identify high risk cases to focus preventive strategies, particularly in low- and middle-income countries (LMICs) where the burden of dementia is greatest. We evaluated the risk of conversion from mild cognitive ompairment (MCI) to dementia in LMICs. Methods Medline, Embase, PsycINFO, and Scopus were searched from inception until June 30, 2020. The search was restricted to observational studies, conducted in population-based samples, with at least 1 year follow-up. There was no restriction on the definition of MCI used as long as it was clearly defined. PROSPERO registration: CRD42019130958. Results Ten thousand six hundred forty-seven articles were screened; n = 11 retained. Of the 11 studies, most were conducted in China (n = 7 studies), with only two studies from countries classified as low income. A qualitative analysis of n = 11 studies showed that similar to high-income countries the conversion rate to dementia from MCI was variable (range 6 0%–44 8%; average follow-up 3 7 years [standard deviation = 1 2]). A meta-analysis of studies using Petersen criteria (n = 6 studies), found a pooled conversion rate to Alzheimer's disease (AD) of 23 8% (95% confidence interval = 15 4%–33.4%); approximately one in four people with MCI were at risk of AD in LMICs (over 3 0–5 8 years follow-up). Risk factors for conversion from MCI to dementia included demographic (e.g., age) and health (e.g., cardio-metabolic disease) variables. Conclusions MCI is associated with high, but variable, conversion to dementia in LMICs and may be influenced by demographic and health factors. There is a notable absence of data from low-income settings and countries outside of China. This highlights the urgent need for research investment into aging and dementia in LMIC settings. Being able to identify those individuals with cognitive impairment who are at highest risk of dementia in LMICs is necessary for the development of risk reduction strategies that are contextualized to these unique settings.National Institute for Health Research (NIHR) Global Group. Grant Number: DePEC 16/137/62https://doi.org/10.1002/trc2.122678pubpub

Risk of conversion from mild cognitive impairment to dementia in low‐ and middle‐income countries: A systematic review and meta‐analysis

Abstract: Introduction: With no treatment for dementia, there is a need to identify high risk cases to focus preventive strategies, particularly in low‐ and middle‐income countries (LMICs) where the burden of dementia is greatest. We evaluated the risk of conversion from mild cognitive ompairment (MCI) to dementia in LMICs. Methods: Medline, Embase, PsycINFO, and Scopus were searched from inception until June 30, 2020. The search was restricted to observational studies, conducted in population‐based samples, with at least 1 year follow‐up. There was no restriction on the definition of MCI used as long as it was clearly defined. PROSPERO registration: CRD42019130958. Results: Ten thousand six hundred forty‐seven articles were screened; n = 11 retained. Of the 11 studies, most were conducted in China (n = 7 studies), with only two studies from countries classified as low income. A qualitative analysis of n = 11 studies showed that similar to high‐income countries the conversion rate to dementia from MCI was variable (range 6 . $.$ 0%–44 . $.$ 8%; average follow‐up 3 . $.$ 7 years [standard deviation = 1 . $.$ 2]). A meta‐analysis of studies using Petersen criteria (n = 6 studies), found a pooled conversion rate to Alzheimer's disease (AD) of 23 . $.$ 8% (95% confidence interval = 15 . $.$ 4%–33.4%); approximately one in four people with MCI were at risk of AD in LMICs (over 3 . $.$ 0–5 . $.$ 8 years follow‐up). Risk factors for conversion from MCI to dementia included demographic (e.g., age) and health (e.g., cardio‐metabolic disease) variables. Conclusions: MCI is associated with high, but variable, conversion to dementia in LMICs and may be influenced by demographic and health factors. There is a notable absence of data from low‐income settings and countries outside of China. This highlights the urgent need for research investment into aging and dementia in LMIC settings. Being able to identify those individuals with cognitive impairment who are at highest risk of dementia in LMICs is necessary for the development of risk reduction strategies that are contextualized to these unique settings

Feasibility and Acceptability of a Dietary Intervention to Reduce Salt Intake and Increase High-Nitrate Vegetable Consumption in Malaysian Middle-Aged and Older Adults with Elevated Blood Pressure: Findings from the DePEC-Nutrition Trial

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420The DePEC-Nutrition trial is a complex dietary and behavioural intervention of salt intake reduction combined with increased high-nitrate vegetable consumption among Malaysian middle-aged and older adults with elevated blood pressure. This study aimed to assess the feasibility and acceptability of the trial. Participants were recruited from the South East Asia Community Observatory (SEACO) database and randomised into one of four groups: (1) low salt; (2) high-nitrate vegetable; (3) combined high-nitrate vegetable and low salt; and (4) control. The intervention included a combination of group counselling sessions, information booklets, reinforcement videos and text messages to modify dietary behaviour. The primary outcomes evaluated were the measures of feasibility and acceptability of (1) recruitment, follow-up attendance and retention; (2) data collection procedures and clinical outcome measures; and (3) individual and combined multi-modal dietary interventions. A total of 74 participants were recruited, and the 10-month retention rate was 73%. Data collection procedures were acceptable with minimal missing data. All intervention strategies were feasible and acceptable, with group counselling being the most acceptable strategy. This study provides important insights into improving the screening process of participants, facilitating their access to the research facilities and refining the measurement protocols and dietary recommendations, which are instrumental in formulating the design of a full-scale definitive DePEC-Nutrition trial.https://doi.org/10.3390/nu1403043014pubpub