Protocol for systematic review and meta-analysis of sex hormones and diabetes risk in ageing men and women of African ancestry

Assessment of the association between plant-based dietary exposures and cardiovascular disease risk profile in sub-Saharan Africa: a systematic review

Background

Studies have investigated dietary attributes associated with cardiovascular disease (CVD) risk in Africa. However, there has been no effort to critically assess the existing evidence. This systematic review examined available evidence on the association between plant-based dietary exposures and CVD risk profile in Africa. PROSPERO registration number: CRD42020159862.

Methods

We conducted a literature search for observational studies reporting on plant-based dietary exposures in relation to CVD risk profile in African populations. PubMed-Medline, Scopus, EBSCOhost, and African Journals Online platforms were searched up to 19 March 2021. Titles and abstracts of the identified records were screened independently by two investigators. The quality of the studies was also assessed independently.

Results

Of 458 entries identified, 15 studies published between 2002 and 2020 were included in this review. These studies originated from 12 sub-Saharan Africa (SSA) countries. Sample sizes ranged from 110 to 2362, age from 18 to 80 years; and majority of participants were females (66.0%). In all, four plant-based dietary exposures were identified across SSA. Sixty percent of the studies reported a significant association between a plant-based dietary exposure with at least one CVD risk factor such as hypertension, diabetes mellitus, dyslipidaemia, overweight/obesity, and metabolic syndrome.

Conclusions

The few available studies suggest that there may be a protective effect of plant-based dietary exposures on CVD risk profile in the African setting. Nonetheless, more elaborated studies are still needed to address plant-based diet (PBD) adherence in relation with CVD risk in African populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12724-w.

Risk of suicidal ideation, suicide attempts, and suicide deaths in persons with sleep apnea: Protocol for a systematic review and meta-analysis

Aim

To estimate the pooled prevalence and incidence of suicidal ideation, attempts, and deaths in people with sleep apnea.

Method

We will identify epidemiological studies reporting the prevalence or incidence rate of suicide in people with sleep apnea. We will search the following databases: PubMed (MEDLINE), Scopus, Cochrane Library, OVID (HEALTH STAR), OVID (MEDLINE) and Joana Briggs Institute EBF Database. No age, geographical location, study-design or language limits will be applied. This protocol was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines. Two reviewers (YY and YP) will independently screen citations, abstracts and will identify full-text articles for inclusion, extract data, and appraise the quality and bias of included studies. Discrepancies will be resolved by consulting with a third researcher (MC). Study quality will be assessed by the Newcastle-Ottawa Scale. The primary outcomes will be the overall prevalence or incidence of suicidal ideation, attempts and completion and the risk of suicide in people with sleep apnea. For pooling of the studies, we will use a random-effects model with a logit transformation. The DerSimonian and Laird (DL) random-effects method will be used to estimate the pooled inter-study variance. We will assess the between-study heterogeneity using I² statistics, and Cochrane’s Q statistic (significance level < 0.05). If the I² is high (>75%), we will perform subgroup meta-analyses and conduct a meta-regression analysis to explore sources of study heterogeneity using study level median age, study-level proportions of race, gender, depression and quality scores. We will report effect estimates as suicide risk per 1000 individuals. Egger’s test and funnel plots will be used to assess publication bias, and adjusted estimates using trim and fill methods will be reported if publication bias is suspected.

Ethics and dissemination

No ethics clearance is required as no primary data will be collected. The results of this systematic review and meta-analysis will be presented at scientific conferences and published in a peer-review journal. The results may shed more light on the burden of suicide risk among individuals with sleep apnea and may guide future population-specific interventions.

Trial registration

PROSPERO registration number: CRD42020165404.

Assessment of the association of plant-based diets with cardiovascular disease risk profile in Africa: a systematic review and meta-analysis protocol

INTRODUCTION

Cardiovascular disease (CVD) is currently the leading cause of death worldwide. In Africa where infectious diseases are still the leading cause of death, the contribution of non-communicable diseases led by CVDs has significantly increased in recent years. The rise of CVDs in Africa is attributed at least in part to the adoption of sedentary behaviours and unhealthy eating habits, which are linked with urbanisation and westernisation of cultures. Dietary attributes associated with CVD risk have been less investigated in Africa. However, evidence from developed nations has reported a protective effect of healthy dietary patterns such as plant-based diets (PBDs) on cardiometabolic health. The current protocol is for a review aiming to assess existing evidence on the association of PBDs with CVD risk profile in African populations.

METHODS AND ANALYSIS

This protocol was developed following the 2015 guidelines of the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols. We will conduct a comprehensive search of the literature for published studies on PBDs in relation to CVD risk profile in African populations. Observational studies published between January 1990 and December 2019 will be screened. A search strategy using keywords and medical subject headings terms will be applied across multiple scientific databases including PubMed-Medline, Scopus and EBSCOhost and the African Journals Online platform. Manual searches of reference lists from relevant articles will be performed. Citations will be traced using the ISI Web of Science to further identify eligible studies. Grey literature will also be screened for relevant abstracts from conference proceedings, and experts in the field will be contacted where appropriate. Two investigators will independently screen all the titles and abstracts to determine which records are eligible for full-text review. Subsequently, two investigators will review the eligible full text using the selection criteria. A third investigator will be consulted to resolve any discrepancies. Data will be extracted from studies that are eligible for the review. Meta-analysis will be performed for studies with similar or comparable methods and reported outcome measures. This will be performed overall, and by major study-level characteristics. Heterogeneity in the estimates across studies will be assessed and quantified with the use of Cochrane Q and I² statistics, respectively. Publication biases will be investigated through funnel plots and Egger test of bias. Relevant sensitivity analyses will be performed to confirm the robustness of the findings.

ETHICS AND DISSEMINATION

The review will analyse data from published studies; therefore, it does not require ethical approval. The findings of the review will be submitted as part of a PhD thesis at Stellenbosch University, South Africa. Additionally, the findings will be presented at conferences and published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42020159862.