| Abstract: |
Objectives Cohort studies of ageing and cognitive decline typically do not
begin fielding comprehensive cognitive assessments until older adulthood.
However, for identifying preventable dementia risk factors, there is strong
value in beginning at earlier ages. The case is especially compelling in
sub-Saharan Africa, where the number of older individuals is expected to
triple in the next three decades, and where risk factors may operate more
intensively at earlier ages. This study reports on the adaptation and validity
of the Harmonised Cognitive Assessment Protocol (HCAP) approach in the Kenya
Life Panel Survey (KLPS), collected among middle-aged respondents. Design To
evaluate the validity of the HCAP approach in Kenya, this study assesses model
fit statistics from confirmatory factor analyses (CFA) and tests measurement
invariance by respondent characteristics. Setting Both rural and urban areas
in Kenya. Participants A sample of n=5878 individuals from the KLPS, who have
been surveyed regularly since they were schoolchildren in the 1990s. The HCAP
assessment was administered in 2023 at an average age of 37 years (10-90 range
34 to 41). Primary and secondary outcome measures For each individual, the CFA
generates a general cognitive performance score, and cognitive performance
scores for five distinct domains, including memory, executive functioning,
language, orientation to time and place, and visuospatial functioning. Results
Fit of the models to the data was adequate for general cognitive performance
(root mean squared error of approximation (RMSEA)=0.03; comparative fit index
(CFI)=0.94; standardised root mean residual (SRMR)=0.05), language
(RMSEA=0.02; CFI=0.95; SRMR=0.05) and good for memory (RMSEA=0.05; CFI=0.99;
SRMR=0.02) and executive functioning (RMSEA=0.03; CFI=0.98; SRMR=0.03). The
CFA indicate that the factor structure is consistent with findings from other
countries and that reliability for the general cognitive performance score was
high. Statistical models also suggest invariance at the scalar level for
leading demographic (gender, age) and socioeconomic (education, occupational
complexity) characteristics. Conclusions This study demonstrates that the
cognitive functioning of mid-age Kenyans appears to be well captured by the
adapted protocol. While there is a moderate decline in cognitive performance
among older individuals, this relationship appears to be mediated by
education, indicating that this KLPS HCAP provides a valuable baseline for
studying future cognitive decline. |
| Keywords: |
Health Services and Systems, Health Sciences, Acquired Cognitive Impairment, Aging, Brain Disorders, Neurodegenerative, Prevention, Behavioral and Social Science, Clinical Research, Neurosciences, Alzheimer's Disease including Alzheimer's Disease Related Dementias (AD/ADRD), Dementia, Basic Behavioral and Social Science, Alzheimer's Disease, Adult, Female, Humans, Male, Middle Aged, Cognitive Aging, Cohort Studies, Kenya, Mental Status and Dementia Tests, Cognition, Reference Standards, Employment, Surveys and Questionnaires, Clinical Sciences, Public Health and Health Services, Other Medical and Health Sciences, Biomedical and clinical sciences, Health sciences, Psychology |