At a Glance
Cognitive Functioning in Middle- and High-Income Countries
Kieron Barclay, Carlos Diaz-Venegas, Mikko Myrskylä, Jo Mhairi Hale (MPIDR / University of St Andrews, United Kingdom); in Collaboration with Rebeca Wong, Alejandra Michaels-Obregon, Rafael Samper-Ternent (all: The University of Texas System, The University of Texas Medical Branch at Galveston, USA), Neil Kishor Mehta (University of Michigan, Ann Arbor, USA)
As people age, they often experience reductions in the levels of cognitive functioning. These declines can affect the quality of life and influence the nature of interpersonal relationships. Reductions in cognition can also limit an individual’s independence when it becomes more difficult to perform common activities such as filling out paperwork or performing everyday calculations. Patterns of cognitive decline are likely to vary by individual characteristics, such as gender, educational attainment, and race/ethnicity. Furthermore, variations in public health conditions, educational systems, and welfare and support systems for the elderly mean that these patterns are likely to differ across countries and over time.
In low- and middle-income countries, older adults tend to live with their adult children and thus enjoy extended familial support. But they must also contend with low levels of institutional support and weak economic conditions, which means that the average individual has a lower level of educational attainment and worse health and has generally experienced tougher socioeconomic conditions over the life course. These experiences may in turn affect the type and the rate of decline in cognitive function that this older individual experiences. In high-income countries, by contrast, a higher percentage of older adults live in institutions such as nursing homes or senior residences, which provide around-the-clock medical attention and allow for some social contact with other seniors. To disentangle these complicated pathways, we apply innovative methodological techniques and exploit data from multiple countries and datasets, including the Mexican Health and Aging Study and the US Health and Retirement Study.
Our results have shown a clear association between early-life exposures and later-life health and cognitive functioning and that these associations may be changing across cohorts. Furthermore, there are mediating and moderating mid- to later-life social factors that are modifiable, such as educational attainment, labor-force participation, and health behaviors. Our policy-relevant findings include that educational attainment appears to be more protective for blacks and Latinx than whites, postponing retirement buffers against cognitive decline, and that, contrary to other literature, trends in dementia are increasing, not declining.
Additional key findings are that all Hispanic subgroups in the United States, with the exception of Cubans, had significantly lower scores for all cognitive domains compared to non-Hispanic whites (NHWs). Among Hispanics, Puerto Ricans had the lowest scores of cognitive functioning in the United States. Our analyses based on the Mexican Health and Aging Study have also revealed important gender differences in cognitive functioning and variations over time between 2001 and 2012. Total cognitive scores and educational attainment were higher for men than they were for women across the whole period. The gender gap in the overall cognition score was smaller in 2012 compared to 2001.
We have also investigated whether fertility history is associated with cognitive functioning among older adults in Mexico. We have found that those who have two or three children have the highest levels of cognitive functioning and that this holds true for men and women. These patterns are likely to be attributable to a mix of selection processes, and they illustrate the benefits of social support from children and family more generally.
Epidemiology 31:5, 745–754. (2020)
SSM-Population Health 11:100577, 1–9. (2020)
In: Contextualizing health and aging in the Americas: effects of space, time and place, 85–107. Cham: Springer. (2019)
Aging and Mental Health 23:11, 1586–1594. (2019)
Psychology and Aging 34:8, 1090–1108. (2019)
Journals of Gerontology, Series B: Psychological Sciences and Social Sciences, 1–13. (2019)
PLoS One 12:12, e0190488–e0190488. (2017)
Demography 54:6, 2125–2158. (2017)