Frailty in Context: Comparative Insights from Older People in Sub-Saharan Africa and African Migrants in Australia

This thesis explores frailty as a dynamic, multidimensional, and context-dependent phenomenon by examining how it is measured, experienced, and associated with health and wellbeing of older people in Sub-Saharan Africa (SSA) and older SSA migrants in Australia. While global research on frailty continues to evolve, much of the evidence and instruments originate in High-Income countries (HICs). This raises concerns about their cultural appropriateness, contextual fit, and equity in frailty screening for populations in Low-and Middle-Income Countries (LMICs) and among migrants from those regions. The geographic and epistemological gap has contributed to the under-representation and potential misclassification of frailty in SSA and migrant contexts. The overarching aim of this thesis is to develop and validate a culturally grounded frailty screening instrument for SSA, and to assess its cross-contextual relevance among older SSA migrants in Australia. It also examines how frailty affects Quality of Life (QoL) across these contexts. The thesis is informed by the Social Determinants of Health (SDH) framework, which emphasises the structural and environmental factors influencing ageing and health trajectories. Specifically, the thesis addresses the suitability of existing frailty instruments in SSA and migrant populations, the feasibility of developing a regionally appropriate instrument and a Frailty Index (FI) threshold, and the contextual mechanisms linking frailty to QoL outcomes. The thesis adopts a multi-method design and comprises eight peer-reviewed research papers structured into three interlinked phases. Phase One involves a synthesis of up-to-date evidence on frailty screening among older people in SSA and older migrants from LMICs to HICs. This phase includes two review papers. The first is a scoping review of seventeen studies that map evidence on how frailty instruments were applied in SSA. The second is a mixed-method systematic review of seven studies that explored the prevalence, perceptions, and experiences of frailty among older migrants from LMICs to HICs. These reviews revealed the misalignment between existing frailty instruments and the structural and cultural realities of both SSA and migrant ageing. Phase Two focuses on developing a regionally grounded frailty screening instrument, and the establishment of a regional FI threshold using secondary data from 5,527 older people (aged 50 years and above) across four SSA countries: Kenya (n = 783), Ghana (n = 3,266), Uganda (n = 461), and Côte d’Ivoire (n = 1,017). A 17-item Frailty instrument for SSA (FiSSA) was developed using a three-step approach of Item-Total Correlation (ITC), Exploratory Factor Analysis (EFA), and Confirmatory Factor Analysis (CFA) based on data from Kenya and Ghana. Additionally, the Receiver Operating Characteristic (ROC) analysis and random-effects meta-analysis were used to establish an FI threshold, using data from all four countries. Further, PROCESS macro for SPSS was utilised to explore how frailty relates to QoL, and how context-specific psychosocial and socioenvironmental factors (digital engagement, perceived safety, and social support) influence this relationship, based on data from Kenya and Ghana. Phase Three aims to validate the FiSSA among a migrant population and examines migration-specific pathways linking frailty to QoL. It draws on primary data collected from 205 older SSA migrants (aged 50 years and above) residing in Australia. Participants were recruited through purposive and snowball sampling within community and cultural networks. FiSSA was validated in the migrant population using CFA, Item Response Theory (IRT), and Relative Weight Analysis (RWA). Further, a moderated mediation modelling using the lavaan package in R was done to test depression and social networks as migration-specific pathways linking frailty to QoL. The FiSSA emerges as a culturally and empirically validated screening instrument that is feasible for use in both SSA and among older SSA migrants in Australia. By integrating structural, psychosocial, and cultural dimensions of ageing, this thesis advances a more inclusive approach to frailty screening. It also contributes to global gerontology by providing tools and evidence to inform clinical practice, shape policy, and advance community-based interventions aimed at promoting equitable and healthy ageing.