Introduction

Abstract

This special issue focuses on contextual factors that contribute to cognitive aging, as they have important implications for prevention and intervention strategies to reduce the global burden of age-related cognitive impairment. Context is defined broadly in terms of geographic residence, socioeconomic conditions, social network characteristics, and the spousal/partner relationship. Each of these lifetime contextual factors has been linked to variability in cognitive development, and the included papers advance this extant literature by examining how these lifespan contexts interact with person-level characteristics in the largest, nationally representative study of aging in the United States (U.S.), the Health and Retirement Study (HRS).

Medical and public health improvements have dramatically increased the adult lifespan. One consequence of longevity is that more and more people are at risk of age-related cognitive decline and dementia. Indeed, the global burden of dementia is expected to double in the next 20 years to 81.1 million. Cognitive decline represents a highly salient detractor to quality of life (Borowiak & Kostka, 2004) and is one of the most frequently identified health concerns of older people (Malani, Kullgren, & Solway, 2017). Further, preserved cognitive functioning is identified as a core component of successful aging (Rowe & Kahn, 1998). While age is the primary risk factor for cognitive decline and dementia, emerging research points to the importance of modifiable risk and protective factors at both individual and contextual levels over the life course (Livingston et al., 2017).

This special issue focuses on contextual factors that contribute to cognitive aging, as they have important implications for prevention and intervention strategies to reduce the global burden of age-related cognitive impairment. Context is defined broadly in terms of geographic residence, socioeconomic conditions, social network characteristics, and the spousal/partner relationship. Each of these lifetime contextual factors has been linked to variability in cognitive development, and the included papers advance this extant literature by examining how these lifespan contexts interact with person-level characteristics in the largest, nationally representative study of aging in the United States (U.S.), the Health and Retirement Study (HRS).

To further understand links between geographic contexts, discrimination and cognitive health, Johnson and colleagues investigate the moderating effect of multiple living environments (rural v. urban and U.S. regions) among older non-Hispanic Blacks. They find that while the discrimation-cogntive health link does not vary by region, it does vary by urbanicity, with more discrimination being significantly associated with lower episodic memory only in urban areas. To advance knowledge on racial/ethnic disparities in physical and cognitive health, Ortiz and colleagues consider interactive effects between race/ethnicity and glycemic control, an important predictor of cognitive aging and dementia. They show that while non-Hispanic Black and Hispanic Americans suffer disproportionately from poor glycemic control, links between glycemic control and cognitive aging do not differ across these racial/ethnic groups. Between-group research demonstrates that racial inequalities in cognitive aging are driven, in part, by disparities in both physical health and socioeconomic status. Taking a within-group approach, Byrd and colleagues demonstrate that chronic health conditions and financial hardship interact to predict episodic memory functioning among non-Hispanic Black Americans. Documenting the distribution of social relations across race/ethnicity is an important step toward understanding the role of modifiable social resources in cognitive health disparities. Katz and colleagues show that friends may be equally available as a resource across race/ethnicity, but that too many or too few family members have a negative effect on executive function for Hispanic and non-Hispanic Black, but not for non-Hispanic White Americans. In the final paper by Leggett and colleagues, couples are examined over eight years beginning with both partners having no cognitive impairment. Levels of loneliness were stable while both partners exhibited no cognitive impairment. However, as a spouse’s cognitive status transitioned to even mild cognitive impairment, the spouse reported significantly elevated levels of loneliness. It is especially noteworthy that this change in spousal loneliness was evident even in early stages of decline and that the impact on loneliness was the same for men and women.

The compiled papers represent scholars from 18 institutions and from multiple disciplines, including public health, social work, developmental psychology, neuropsychology, and sociology. The interdisciplinary work contained in this special issue was conceived and initiated at the first annual Summer Data Immersion program hosted by the Michigan Center for Contextual Factors in Alzheimer’s Disease (MCCFAD), an NIA-funded Resource Center for Minority Aging Research. This competitive program advances MCCFAD’s goal of eliminating racial/ethnic inequalities in Alzheimer’s disease and related dementias by providing hands-on training in the use of publicly available data resources to address relevant questions and by catalyzing new research collaborations among diverse scholars.

By disseminating some of the first interdisciplinary research projects undertaken at the MCCFAD Summer Data Immersion program, this special issue provides a rigorous examination of lifespan contextual factors that shape adult cognitive development, with a particular emphasis on racial/ethnic disparities in cognitive aging. By examining multiple lifespan contextual factors among different subpopulations of a single, nationally-representative study of adults over the age of 50, the included papers provide unique insights into cognitive development and risk of Alzheimer’s disease.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Michigan Center for Contextual Factors in Alzheimer’s Disease, a Resource Center for Minority Aging Research funded by the National Institute on Aging [AG059300].