Late-life disability trajectories in Yoruba Nigerians and the Spanish population: a state space model in continuous time

Abstract

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 (µ_ADL80=0.44, SE = 0.015, p < 0.001), Spanish older adults had higher disability scores (µ_ADL80=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:

• Functional disability
• ADL limitations
• compression of disability
• low- and middle-income countries
• longitudinal cohort

Disclosure statement

The authors declare that they do not have any conflict of interest to disclose.

Authors contribution

All the authors significantly contributed to this manuscript. AO, ATL, DMA and EL were involved in research question formulation and study design. DMA, EL, FFC, JLAM, JMH, TB, AO, OG and BO carried out the data collection. EEM and ATL analysed the data. AO, ATL and EE wrote the manuscript. All the authors reviewed the manuscript.

Notes

1 For this analysis, only the participants with information in all the covariates considered at each step were included. Therefore, the final model for the Spanish sample with 3 covariates included 1573 cases.

Additional information

Funding

This study was supported by the Wellcome Trust (grant no: WT079662MF) and the European Community’s Seventh Framework Programme (FP7/2007–2013, grant agreement 223071, COURAGE in Europe), the European Commission Horizon 2020 (grant agreement 635316, ATHLOS), the Spanish Ministry of Economy and Competitiveness (ACI2009-1010), and the Instituto de Salud Carlos III-FIS research grants (PS09/00295, PS09/01845, PI12/01490, PI13/00059, PI16/00173, PI16/00218, PI20/229). Projects PI12/01490, PI13/00059, PI16/00173, PI16/00218, and PI20/229 was co-funded by the European Regional Development Fund (ERDF) “A Way to Build Europe”. The work was also supported by the CIBERSAM. AO is supported by NIHR-Wellcome Global Health Partnership International Intermediate Fellowship (Ref: 220684/Z/20/Z). EE was supported by the Ministry of Science and Innovation of Spain (ref. PID2019-107570GA-I00/AEI/doi:10.13039/501100011033). EL’s work is supported by Juan de la Cierva postdoctoral programme (Ref. IJC2019-041846-I) from the Spanish Ministry of Science and Innovation. DMA is supported by the ESRC Centre for Society and Mental Health at King’s College London (ESRC Reference: ES/S012567/1). The views expressed are those of the author(s) and not necessarily those of their institutions.