Vitamin D Status in Ghana: A Mixed-Methods Narrative Review of Prevalence, Determinants, Comorbidity Burden, and Spatial Distribution with Study-Level Risk Prediction Alternative (shorter): Vitamin D Deficiency in Ghana: An Integrative Mixed-Methods Review of Epidemiology, Geographic Patterns, Clinical Associations, and Predictive Modeling

Description Background and Rationale Vitamin D Deficiency (VDD) has recently become a more prominent and prevalent public health issue that has been documented in countries worldwide, including countries located in the tropics like Ghana. It has been assumed that due to the availability of sun exposure, one would be able to synthesize vitamin D adequately and therefore mitigate VDD-related health issues. However, an increasing body of research has indicated that despite the abundance of solar irradiation, Ghanaians of all demographics and various clinical conditions have an alarmingly high VDD prevalence. Low vitamin D status has been associated with a number of health conditions, including metabolic (e.g. type 2 diabetes), negative pregnancy (e.g. preeclampsia and low birth weight), inflammatory (e.g. rheumatoid arthritis), and psychiatric disorders. However, the research that has been conducted in Ghana regarding vitamin D has been mostly isolated and therefore has limited the ability to analyze national-level patterns of vitamin D status, identify high-risk populations, and develop public health strategies that could address the problem. Objectives The objectives of this mixed methods narrative review include: - Estimating the pooled prevalence and demographic distribution of vitamin D deficiency in the sub populations of the Ghanaian population (such as healthy adults, pregnant women, and chronically ill patients) and the defining parameters of the study population. - Defining the relationship between vitamin D deficiency and some important comorbidities which include type 2 diabetes, chronic liver disease, rheumatoid arthritis, psychosocial disorders, and negative pregnancy outcomes. - Using geospatial epidemiology techniques to assess the geographic distribution and identify the spatial hotspots of vitamin D deficiency in the 16 administrative regions of Ghana. - Using random effects meta-regression and decision tree risk stratification to assess study level predictors of vitamin D deficiency prevalence. - Thematic synthesis of findings regarding the socio-cultural, dietary, health care system, and environmental factors that have been reported to influence vitamin D status in the included studies. Methods Design: As per PRISMA-ScR, this narrative review is designed as a mixed-method approach. The review protocol was registered on OSF a priori. Your given text is quite informative and systematic, and there is little opportunity to fully change it without affecting understanding. However, I can present it in a somewhat different way, slightly different structure and font, yet also informative and systematic.\\ Systematic search in PubMed, Scopus, Web of Science, and African Journals Online (AJOL) will be conducted from inception to March 2025. Searches will be conducted using MeSH and free terms: \\"vitamin D\\" OR \\"25-hydroxyvitamin D\\" OR \\"25(OH)D\\" OR \\"cholecalciferol\\" AND \\"Ghana\\" OR \\"Ghanaian\\" or any related regional terms. Manually screened reference lists of relevant studies. Search Strategy: Eligibility Criteria: Inclusion: (1) Measured serum 25(OH)D using validated assay (ELISA or LC-MS/MS); (2) Participants included residing in Ghana; (3) 25(OH)D (ng/mL) mean, SD, and/or VDD prevalence reported; (4) Peer reviewed original research Exclusion: Case reports (n<10), KAP studies without biochemical data, studies that are editorial, review, or exclusively dietary intake. VDD is defined as serum 25(OH)D <20 ng/mL (<50 nmol/L). Quality Assessment & Data Extraction: Data will be extracted by two independent reviewers using a standardized form: author, year, region(s), design, population, N, mean 25(OH)D, SD, VDD%, assay method, comorbidities, and qualitative notes. Quality of the methods will be evaluated using the Newcastle-Ottawa Scale (NOS) for cross-sectional and case-control designs. Analytical Approaches: Quantitative synthesis: Weighted pooled prevalence and mean 25(OH)D using inverse-variance weights; subgroup analysis by population, region, assay type. Spatial analysis: Geographic mapping using administrative division shapefiles of Ghana; Global Moran's I for spatial autocorrelation and hotspot analysis with Getis-Ord Gi*. Qualitative synthesis: Reflexive thematic analysis (Braun & Clarke) of the authors’ reports in the determinant, facilitator, barrier, and policy related recommendations within the discussion. Predictive modeling: Study-level meta-regression, combined with decision-tree stratification, to determine predictive factors for VDD prevalence (region, population type, assay method, year of publication, NOS score). Integration involves the alignment of quantitative results, spatial distributions, and qualitative themes using joint displays and narrative weaving. Expected Outcomes and Contributions A geographically stratified evidence base on vitamin D deficiency (VDD) and risk factors in the Ghana setting. High VDD prevalence areas and vulnerable population subgroups that can inform screening and supplementation interventions. Socio-cultural, dietary, and healthcare-system-related barriers that explain the sufficiency of vitamin D. A synthesis that is transparent and reproducible along the lines of the PRISMA-ScR framework, with public access to all the materials including data, codes, shapefiles, and the whole synthesis on the OSF. Feasible and evidence-based recommendations on the incorporation of vitamin D screening into Ghana’s and other sub-Saharan African countries’ antenatal care, chronic disease management, and public health nutrition interventions. Registration and Transparency Prior to conducting the full-text screening, this protocol was registered on the Open Science Framework (OSF). Any changes made to the protocol will be thoroughly explained in the final manuscript. For reproducibility and secondary analyses, analysis codes, fetched data, and Ghana’s shapefiles will be made publicly accessible upon publication.