Objectives: We compared the trajectory of activities of daily living (ADL) in a nationally representative sample of older Nigerians with their Spanish peers and identified factors to explain country-specific growth models.
Methods: Data from two household multistage probability samples were used, comprising older adults from Spain (n = 2,011) and Nigeria (n = 1,704). All participants underwent assessment for ADL. Risk factors including sex, household income, urbanicity, years of education, depression, alcohol consumption and smoking were assessed using validated methods. State-space model in continuous time (SSM-CT) methods were used for trajectory comparison.
Results: Compared with Nigerians (µADL80=0.44, SE = 0.015, p < 0.001), Spanish older adults had higher disability scores (µADL80=1.23, SE = 0.021, p < 0.001). In SSM-CT models, the rate of increase in disability was faster in Nigerians (Nigeria: β = 0.061, p<.01; Spain: β = 0.028, p < 0.010). An increasing course of disability in the Spanish sample was predicted by female sex, lower education and depression diagnosis.
Conclusion: The rate of increase in disability was faster in older Nigerians living in an economically disadvantaged context.
Keywords: ADL limitations; Functional disability; compression of disability; longitudinal cohort; low- and middle-income countries.