Association between oral health status and cardiovascular disease outcomes in Africa; A scoping review

Research Project Description: The Association Between Oral Health Status and Cardiovascular Disease Among African Adults This research project is a scoping review focusing on health issues among African populations. Its aim is to systematically collate and synthesize existing evidence regarding the association between oral health status (with a specific focus on periodontal disease and dental caries) and cardiovascular disease (CVD) outcomes (such as myocardial infarction, stroke, and hypertension) in African adults. By addressing the research gaps in this field within the African context, the project seeks to provide a scientific basis for the development of targeted health strategies. The following sections will elaborate on the core background, clear objectives, systematic methodologies, expected outcomes, and potential value of the research, offering a comprehensive overview of the project's framework and key significance. I. Research Background: Focusing on the Unresolved Association of Dual Disease Burdens in Africa Cardiovascular disease (CVD) has become the leading cause of death in Africa. Its high incidence and mortality rates impose a heavy burden on the healthcare systems of African countries, seriously affecting the quality of life and population health development of local residents. Meanwhile, oral diseases are also highly prevalent in Africa, with periodontal disease and dental caries being the two most common types. These conditions not only impair residents' oral function and quality of life but also may exert profound impacts on systemic health through various underlying mechanisms. In high-income countries, numerous epidemiological studies and clinical evidence have clearly confirmed a close association between poor oral health and adverse CVD outcomes, with oral health problems recognized as one of the important risk factors for CVD. However, evidence supporting this association in African populations remains extremely limited, and the characteristics of existing studies are inadequately described. Africa differs significantly from high-income countries in terms of population genetic background, lifestyles, dietary habits, accessibility to healthcare resources, and disease prevention and treatment systems. These factors may lead to unique patterns of association, strength of effect, and underlying mechanisms between oral health and CVD. Therefore, conducting specialized research on African populations to systematically clarify this association has become an urgent and important issue in the field of public health in Africa. II. Research Objectives: Systematically Synthesizing Evidence to Clarify Core Associations The core objective of this study is to conduct a rigorous and standardized scoping review to comprehensively search, screen, and synthesize globally published research literature focusing on African adult populations. It aims to systematically analyze the characteristics of the association between oral health status (with periodontal disease and dental caries as core evaluation indicators) and CVD outcomes (including major CVD types such as myocardial infarction, stroke, and hypertension). The specific objectives include: 1. Systematically summarize the current status of research on the association between oral health and CVD in Africa, and clarify the quantity, geographical distribution, study design types, and core research content of existing studies; 2. Quantitatively analyze the epidemiological burden of periodontal disease, dental caries, and the incidence of CVD among African adults, providing epidemiological data support for understanding the basis of their association; 3. In-depth explore the strength of the association between oral health status and CVD outcomes, with a focus on differences in this association among different population subgroups (such as adults with comorbid diabetes and children with rheumatic heart disease (RHD)); 4. Summarize the potential biological mechanisms underlying the association proposed in existing studies, such as systemic inflammation and elevated levels of oral pathogens, to provide directions for subsequent mechanistic research; 5. Identify the limitations and gaps in current research, and provide specific recommendations for conducting more targeted research in Africa in the future. III. Research Methods: Adhering to Standardized Frameworks to Ensure Reliable Results To ensure the systematicity, scientificity, and reliability of the research, this study strictly adheres to the scoping review framework proposed by Arksey and O'Malley and refers to the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) guidelines. The specific methods are as follows: 1. Literature Search Strategy The research team has developed a comprehensive literature search strategy, selecting globally influential academic databases as search platforms, including PubMed, CINAHL, Google Scholar, and Web of Science. The search timeframe is set from January 1, 2000, to June 30, 2025, to ensure coverage of the latest research findings in recent years while incorporating classic literature within a certain time span to guarantee the comprehensiveness of evidence. The search keyword combinations revolve around core concepts such as "oral health," "periodontal disease," "dental caries," "cardiovascular disease," "myocardial infarction," "stroke," "hypertension," "Africa," and "adults." A combination of subject terms and free terms is used for searching to minimize literature omission. 2. Inclusion and Exclusion Criteria for Literature To ensure the quality and relevance of included studies, this research has established clear inclusion and exclusion criteria. The inclusion criteria are as follows: (1) The study type is peer-reviewed academic papers to ensure that the research quality has undergone professional verification; (2) The study population consists of African adults (aged ≥ 18 years), and some studies involving child populations closely related to adult health (such as children with rheumatic heart disease) are also included; (3) The research content explicitly explores the association between oral health status and CVD outcomes; (4) Both oral health status and CVD outcomes are evaluated using validated standardized measurement tools or diagnostic criteria to ensure the accuracy and comparability of research data. The exclusion criteria include: non-peer-reviewed literature (such as conference abstracts, preliminary thesis drafts, etc.), studies with non-African populations or inconsistent age groups, studies whose content does not involve the association between the two, and studies using unvalidated measurement tools. 3. Literature Screening and Data Extraction Literature screening is conducted through a dual-independent screening method. First, literature that clearly does not meet the inclusion criteria is excluded by reading titles and abstracts. Subsequently, full-text reading is performed on literature that potentially meets the criteria to finally determine the list of included studies. In case of discrepancies during the dual-screening process, they are resolved through group discussions or consultation with third-party professional researchers. Data extraction is also completed independently by two researchers. The extracted content includes basic study information (authors, publication year, research region), study design, sample size, characteristics of the study population, oral health evaluation indicators and results, definition and incidence of CVD outcomes, analysis results of the association between the two, and discussion on potential mechanisms. A standardized data extraction form is established to ensure the completeness and accuracy of data extraction. IV. Expected Outcomes: Clarifying Association Characteristics to Guide Future Directions Based on the above research methods, this study is expected to yield a series of outcomes with significant academic value and practical significance, mainly including the following aspects: 1. Clarifying the Core Characteristics of Existing Research in Africa This study is expected to confirm that the number of existing studies on the association between oral health and CVD among African populations is limited, and there is a concentrated geographical distribution. According to preliminary screening results, there are only 4 studies that meet the inclusion criteria, conducted in Cameroon, Mauritius, Mozambique, and Ghana respectively. This indicates significant geographical imbalance in research in this field across Africa, with many African countries having not yet carried out relevant research. Meanwhile, all existing studies adopt a cross-sectional study design, lacking longitudinal cohort studies and interventional studies, which also points out directions for subsequent study design. 2. Quantitatively Presenting the Dual Disease Burden and Core Associations The study is expected to systematically present the high epidemiological burden of oral diseases and CVD among the included African study populations: the prevalence of periodontal disease can be as high as 77.2%, meaning that nearly 80% of the study participants are affected by periodontal disease; in one study involving children, dental caries also affects a significant proportion of children; among adult populations, the prevalence of CVD is as high as 28.9%, further confirming the severe epidemic situation of these two diseases in Africa. More importantly, the study is expected to clearly confirm a significant association between poor oral health and CVD in African populations, and this association is more prominent in specific subgroups, such as adults with comorbid diabetes and children with rheumatic heart disease, which provides a key basis for identifying high-risk populations. 3. Summarizing Potential Biological Mechanisms and Research Gaps This study is expected to integrate the potential biological mechanisms underlying the association proposed in existing studies, among which the core mechanisms include systemic inflammation and elevated levels of oral pathogens. Oral diseases, especially periodontal disease, can lead to local inflammatory responses in the oral cavity. If the inflammation persists, inflammatory factors will enter the bloodstream, triggering a systemic chronic inflammatory state, which in turn damages vascular endothelial cells, promotes the occurrence and development of atherosclerosis, and ultimately increases the risk of CVD. At the same time, pathogenic bacteria in the oral cavity may also reach the cardiovascular system through routes such as hematogenous spread, directly or indirectly participating in the pathological process of CVD. In addition, the study is expected to identify two core gaps in current research: first, the total amount of evidence is limited, making it difficult to form comprehensive and stable conclusions; second, the geographical distribution of research is concentrated, lacking coverage of populations in different regions and countries with different economic development levels in Africa, and the representativeness of research results needs to be improved. 4. Proposing Targeted Research Recommendations and Practical Implications Based on the research findings, this project is expected to put forward a series of operable recommendations: at the research level, there is an urgent need to expand the research scale and carry out more studies targeting different regions and populations in Africa. In particular, longitudinal cohort studies should be strengthened to clarify the causal association between the two, and interventional studies should be conducted to explore the feasibility of preventing CVD by improving oral health; at the practical level, the research results will provide a scientific basis for African countries to formulate integrated oral health and cardiovascular health strategies, promoting the establishment of interdisciplinary collaboration mechanisms in the healthcare system. By integrating oral health management into the prevention and control system of CVD, improving the oral health level of residents, reducing the incidence risk of CVD, and ultimately alleviating the dual disease burden in Africa. V. Research Value: Filling Gaps to Serve Public Health Practice in Africa As a scoping review focusing on specific health issues in Africa, the academic value and practical significance of this study are mainly reflected in the following aspects: from an academic perspective, this study is the first to systematically integrate existing evidence on the association between oral health and CVD among African populations, clarifying the current research status and core gaps in this field, and providing a clear direction and theoretical basis for subsequent research; from a practical perspective, the research results will directly provide scientific references for public health policy-makers in African countries, promoting the establishment of an integrated "oral health-cardiovascular health" prevention and management model. Through targeted intervention measures (such as strengthening oral health education, improving the accessibility of oral medical services, and conducting oral health screenings in high-risk populations for CVD), the incidence and mortality rates of both diseases can be effectively reduced, ultimately improving the overall health level of African residents and contributing significantly to the development of public health in Africa.