Gut microbiota diversity and markers of cardiovascular risk among older adults: a scoping review

Background Advancing age independently predicts cardiovascular diseases (CVDs), a leading cause of global morbidity and mortality. Emerging evidence links gut microbiota to CVD risk, yet studies in older adults remain limited, fragmented, and methodologically heterogeneous. To address this gap, we conducted a scoping review to map existing evidence, identify research gaps and inform microbiota-targeted strategies for cardiovascular health in ageing populations. Methods Following the Joanna Briggs Institute framework, a comprehensive search of PubMed, Scopus, Cochrane and AJOL was conducted for studies assessing gut microbiota in relation to CVD morbidity among older adults (mean/median age ≥60 years or including stratified analyses). Eligible studies included observational, and interventional studies published in English without date restrictions. Data were extracted using a standardised form and synthesised descriptively to summarise key findings, methodologies and gaps. Results Four studies met inclusion criteria. Altered gut microbiota, particularly reduced diversity, depletion of short-chain fatty acid producing taxa and elevated pro-atherogenic metabolites were associated with hypertension, heart failure and arterial stiffness. However, most studies originated from high-income countries, were predominantly cross-sectional and applied heterogeneous analytical approaches, underscoring a lack of longitudinal and region-specific evidence in older adults. Conclusions Alterations in gut microbiota composition may be associated with cardiovascular risk markers in older adults; however, available evidence remains preliminary. Robust longitudinal and intervention studies are warranted to better understand these associations and their implications for cardiovascular health and disease prevention in ageing populations.