Social isolation and 9-year dementia risk in community-dwelling Medicare beneficiaries in the United States

Your doctor needs to get you 100% recovered immediately before you lose the first two groups of friends that Aristotle describes.  DEMAND results or your doctor will use the craptastic saying; 'All strokes are different, all stroke recoveries are different'. You can't allow your doctor to hide and cower behind that useless saying.

Aristotle believes that there are three different kinds of friendship; that of utility, friendship of pleasure, and virtuous friendship. 

and that you will likely lose all of the first two post stroke?

Social isolation and 9-year dementia risk in community-dwelling Medicare beneficiaries in the United States

Alison R. Huang PhD, David L. Roth PhD, Tom Cidav MS, Shang-En Chung ScM, Halima Amjad MD, MPH, PhD, Roland J. Thorpe Jr. PhD, Cynthia M. Boyd MD, MPH … See all authors

First published: 11 January 2023

https://doi.org/10.1111/jgs.18140

Funding information: National Institute on Aging, Grant/Award Numbers: 1F31AG072746, 1P30AG066587-01, 3K24AG056578-02S1, 5R03AG064253, K02AG059140, K23 AG064036, K24 AG056578, P30AG059298; National Institute on Minority Health and Health Disparities, Grant/Award Number: U54MD000214; Secunda Family Foundation

Abstract

Background

Social isolation can influence whether older adults develop dementia. We examine the association between social isolation and incident dementia among older adults in a nationally representative sample of community dwelling older adults in the United States (U.S.). We also investigate whether this association varies by race and ethnicity.

Methods

Data (N = 5022) come from the National Health and Aging Trends Study, a longitudinal and nationally representative cohort of older adults in the U.S. A composite measure of social isolation was used to classify older adults as socially isolated or not socially isolated at baseline. Demographic and health factors were measured at baseline via self-report. Dementia was measured at each round of data collection. Discrete-time proportional hazard time-to-event models were used to assess the association between social isolation and incident dementia over 9 years (2011–2020).

Results

Of 5022 older adults, 1172 (23.3%) were socially isolated, and 3850 (76.7%) were not socially isolated. Adjusting for demographic and health factors, being socially isolated (vs. not socially isolated) was associated with a 1.28 (95% CI: 1.10–1.49) higher hazard of incident dementia over 9 years. There was no statistically significant difference by race and ethnicity.

Conclusion

Social isolation among older adults is associated with greater dementia risk. Elucidating the pathway by which social isolation impacts dementia may offer meaningful insights for the development of novel solutions to prevent or ameliorate dementia across diverse racial and ethnic groups.

Key points

• Among older adults in the United States, social isolation is common (1 in 4 adults experience social isolation) and associated with higher hazard of incident dementia over 9 years.
• There were no observed differences in the association between social isolation and dementia by race and ethnicity.

Why does this paper matter?

Social isolation may be a valuable and modifiable risk factor to target in interventions for reducing dementia risk across diverse racial and ethnic groups.

INTRODUCTION

There is mounting evidence linking social isolation in older adults to greater risk of dementia. Social isolation is defined as an “objective state of having few social relationships or infrequent social contact with others.”¹ Social isolation is a multi-dimensional construct characterized by structural (e.g., existence of social connections), functional (e.g., social support, resource sharing), and quality factors (e.g., relationship strain).¹ In the United States, social isolation impacts approximately 1 in 4 older adults.^{2, 3}

Prior studies suggest socially isolated older adults have a higher risk of incident dementia,^4-7 but no study, to our knowledge, has described this longitudinal association in a nationally representative cohort of older adults in the United States (U.S.). Prior studies of U.S. older adults found associations between certain aspects of social isolation (e.g., poor social engagement, poor social support) and dementia, but these studies focused on older adults living in specific metropolitan areas^8-11 and/or older adults with specific demographic characteristics (e.g., older women).¹²

Our study was informed by the conceptual foundation that upstream social and personal resources are linked to downstream health outcomes, including cognitive health and function^{13, 14} as well as the National Institutes of Aging Health Disparities Research Framework.¹⁵ Studies (within and outside the U.S.) have also yet to assess race and ethnicity group specific associations between social isolation and dementia. The U.S. population of older adults is racially and ethnically diverse and will continue to become more diverse over the next decades.¹⁶ It is important to understand how risk factors may impact dementia risk differently across race and ethnicity, especially in the U.S. The social isolation-dementia association may differ by race and ethnicity given disparities in both dementia incidence and prevalence of social isolation. Dementia incidence is higher in African American, Hispanic, American Indian, or Alaska Native older adults compared to White older adults.^{17, 18} Some studies have also found that social isolation is more prevalent in African American and Hispanic older adults (vs. White)¹⁹ but findings are mixed.^{1, 2}

In the current study, we examine the association between social isolation and incident dementia over 9 years in a large and nationally representative sample of Medicare beneficiaries in the US. We also assess differences in the social isolation—incident dementia association by race and ethnicity. This longitudinal study is the first, to our knowledge, to investigate potential racial and ethnic disparities in the association between social isolation and incident dementia.

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