The “loneliness epidemic” is a major public health concern, and its effects can be especially adverse in older adults.
Objective
The current study used longitudinal data to investigate the associations between loneliness, cognitive function and decline, and dementia risk.
Methods
Data were derived from older adults (n = 5730 at the baseline) who participated in the 2008–2018 Health and Retirement Study (HRS). We fit cross-lagged panel as well as linear and logistic regression models, accounting for the complex design of HRS, to assess the bi- and uni-directional relationship between loneliness and cognitive function/decline/dementia risk, sequentially adjusting for social determinants of health, health conditions, and functional limitations. We tested for modifications by race/ethnicity.
Results
We found low support for a bidirectional association between loneliness and cognitive function. Instead, higher levels of loneliness were linked to more pronounced cognitive decline as well as a higher risk of dementia prevalence and incidence, irrespective of race/ethnicity. Education partially attenuated the relationship, and overall functional limitations further reduced the associations.
Conclusions
Findings suggest that education and overall functional limitations can play an important role through several pathways, such as increasing social engagement, facilitating social support and cognitive stimulation, and thus reducing the impact of loneliness on cognitive decline and dementia risk.
MurthyVH. COVID-19 pandemic underscores the need to address social isolation and loneliness. Public Health Rep2021; 136: 653–655.
2.
CacioppoJTCacioppoS. The growing problem of loneliness. Lancet2018; 391: 426.
3.
LippkeSWarnerLM. Understanding and overcoming challenges in times of personal or global crisis—editorial on the special issue on loneliness and health. Appl Psychol Health Well Being2023; 15: 3–23.
4.
Cohn-SchwartzEJoshiRMcClureLA. The associations of loneliness and social support with cognitive impairment among middle-aged and older individuals with diabetes. Int J Environ Res Public Health2023; 20: 1885.
5.
SutinARStephanYLuchettiM, et al.Loneliness and risk of dementia. J Gerontol B Psychol Sci Soc Sci2020; 75: 1414–1422.
6.
HugoJGanguliM. Dementia and cognitive impairment: epidemiology, diagnosis, and treatment. Clin Geriatr Med2014; 30: 421–442.
7.
PerlmanDPeplauLA. Toward a social psychology of loneliness. Pers Relatsh1981; 3: 31–56.
8.
HawkleyLCCacioppoJT. Loneliness matters: a theoretical and empirical review of consequences and mechanisms. Ann Behav Med2010; 40: 218–227.
9.
HeinrichLMGulloneE. The clinical significance of loneliness: a literature review. Clin Psychol Rev2006; 26: 695–718.
10.
CacioppoJPatrickW. Loneliness: human nature and the need for social connection. Am J Psychiatry2008; 166: 375–376.
11.
BarretoMVictorCHammondC, et al.Loneliness around the world: age, gender, and cultural differences in loneliness. Pers Individ Dif2021; 169: 110066.
12.
Holt-LunstadJSmithTBBakerM, et al.Loneliness and social isolation as risk factors for mortality: a meta-analytic review. Perspect Psychol Sci2015; 10: 227–237.
13.
BruceLDWuJSLustigSL, et al.Loneliness in the United States: a 2018 national panel survey of demographic, structural, cognitive, and behavioral characteristics. Am J Health Promot2019; 33: 1123–1133.
14.
PoeyJLBurrJARobertsJS. Social connectedness, perceived isolation, and dementia: does the social environment moderate the relationship between genetic risk and cognitive well-being?Gerontologist2017; 57: 1031–1040.
15.
KuiperJSZuidersmaMVoshaarRCO, et al.Social relationships and risk of dementia: a systematic review and meta-analysis of longitudinal cohort studies. Ageing Res Rev2015; 22: 39–57.
16.
SalinasJBeiserASSamraJK, et al.Association of loneliness with 10-year dementia risk and early markers of vulnerability for neurocognitive decline. Neurology2022; 98: e1337–e1348.
17.
JacksonKLLuoJWillrothEC, et al.Associations between loneliness and cognitive resilience to neuropathology in older adults. J Gerontol B Psychol Sci Soc Sci2023; 78: 939–947.
18.
JoshiMSGalvinJE. Cognitive resilience in brain health and dementia research. J Alzheimers Dis2022; 90: 461–473.
19.
ZahodneLBGlymourMMSparksC, et al.Education does not slow cognitive decline with aging: 12-year evidence from the Victoria longitudinal study. J Int Neuropsychol Soc2011; 17: 1039–1046.
20.
WalsemannKMAilshireJA. Early educational experiences and trajectories of cognitive functioning among US adults in midlife and later. Am J Epidemiol2020; 189: 403–411.
21.
SohYWhitmerRAMayedaER, et al.State-level indicators of childhood educational quality and incident dementia in older black and white adults. JAMA Neurol2023; 80: 352–359.
22.
FletcherJToppingMZhengF, et al.The effects of education on cognition in older age: evidence from genotyped siblings. Soc Sci Med2021; 280: 114044.
23.
CroweMClayOJMartinRC, et al.Indicators of childhood quality of education in relation to cognitive function in older adulthood. J Gerontol A Biol Sci Med Sci2012; 68: 198–204.
24.
SohYWhitmerRAMayedaER, et al.Timing and level of educational attainment and late-life cognition in the KHANDLE study. Alzheimers Dement2024; 20: 593–600.
25.
YuBSteptoeAChenY, et al.Social isolation, rather than loneliness, is associated with cognitive decline in older adults: China health and retirement longitudinal study. Psychol Med2021; 51: 2414–2421.
26.
GriffinSCMezukBWilliamsAB, et al.Isolation, not loneliness or cynical hostility, predicts cognitive decline in older Americans. J Aging Health2020; 32: 52–60.
27.
WangHLeeCHunterS, et al.Longitudinal analysis of the impact of loneliness on cognitive function over a 20-year follow-up. Aging Ment Health2020; 24: 1815–1821.
28.
LeeJHLuchettiMAschwandenD, et al.Cognitive impairment and the trajectory of loneliness in older adulthood: evidence from the health and retirement study. J Aging Health2022; 34: 3–13.
29.
CamachoDPachecoKMoxleyJ, et al.Loneliness and global cognitive functioning in racially and ethnically diverse US midlife and older adults. Front Psychol2024; 15: 1344044.
30.
WrightCBDeRosaJTMoonMP, et al.Race/ethnic disparities in mild cognitive impairment and dementia: the northern Manhattan study. J Alzheimers Dis2021; 80: 1129–1138.
31.
TaylorHOChenYCTsuchiyaK, et al.Racial/ethnic differences in loneliness among older adults: the role of income and education as mediators. Innov Aging2024; 8: igae068.
32.
KannanVDVeaziePJ. US Trends in social isolation, social engagement, and companionship ⎯ nationally and by age, sex, race/ethnicity, family income, and work hours, 2003–2020. SSM Popul Health2023; 21: 101331.
33.
RaymoJMWangJ. Loneliness at older ages in the United States: lonely life expectancy and the role of loneliness in health disparities. Demography2022; 59: 921–947.
34.
PluimCFAnzaiJAUMartinezJE, et al.Associations among loneliness, purpose in life and subjective cognitive decline in ethnoracially diverse older adults living in the United States. J Appl Gerontol2023; 42: 376–386.
35.
DesaiPKruegerKRde LeonCM, et al.Race and apolipoprotein E-e4 allele status differences in the association between loneliness and cognitive decline. Psychosom Med2023; 85: 231–237.
36.
SonnegaAFaulJDOfstedalMB, et al.Cohort profile: the health and retirement study (HRS). Int J Epidemiol2014; 43: 576–585.
37.
RussellDPeplauLACutronaCE. The revised UCLA loneliness scale: concurrent and discriminant validity evidence. J Pers Soc Psychol1980; 39: 472–480.
38.
LeeJCagleJG. Validating the 11-item revised university of California Los Angeles scale to assess loneliness among older adults: an evaluation of factor structure and other measurement properties. Am J Geriatr Psychiatry2017; 25: 1173–1183.
39.
CrimminsEMKimJKLangaKM, et al.Assessment of cognition using surveys and neuropsychological assessment: the health and retirement study and the aging, demographics, and memory study. J Gerontol B Psychol Sci Soc Sci2011; 66: i162–i171.
LuchettiMTerraccianoAAschwandenD, et al.Loneliness is associated with risk of cognitive impairment in the survey of health, ageing and retirement in Europe. Int J Geriatr Psychiatry2020; 35: 794–801.
42.
LivingstonGHuntleyJLiuKY, et al.Dementia prevention, intervention, and care: 2024 report of the lancet standing commission. Lancet2024; 404: 572–628.
43.
Akhter-KhanSCTaoQAngTFA, et al.Associations of loneliness with risk of Alzheimer's disease dementia in the Framingham heart study. Alzheimers Dement2021; 17: 1619–1627.
44.
SundströmAAdolfssonANNordinM, et al.Loneliness increases the risk of all-cause dementia and Alzheimer's disease. J Gerontol B Psychol Sci Soc Sci2020; 75: 919–926.
45.
HolwerdaTJDeegDJBeekmanAT, et al.Feelings of loneliness, but not social isolation, predict dementia onset: results from the Amsterdam study of the elderly (AMSTEL). J Neurol Neurosurg Psychiatry2014; 85: 135–142.
46.
CardonaMAndrésP. Are social isolation and loneliness associated with cognitive decline in ageing?Front Aging Neurosci2023; 15: 1075563.
47.
NortonSMatthewsFEBarnesDE, et al.Potential for primary prevention of Alzheimer's disease: an analysis of population-based data. Lancet Neurol2014; 13: 788–794.
48.
GuarneraJYuenEMacphersonH. The impact of loneliness and social isolation on cognitive aging: a narrative review. J Alzheimers Dis Rep2023; 7: 699–714.
49.
HtunHLTeshaleABSunH, et al.Changes in loneliness, social isolation, and social support: a gender-disaggregated analysis of their associations with dementia and cognitive decline in older adults. Int J Geriatr Psychiatry2025; 40: e70065.
50.
DonovanNJWuQRentzDM, et al.Loneliness, depression and cognitive function in older U. S. Adults. Int J Geriatr Psychiatry2017; 32: 564–573.
51.
HanSDAdeyemiOWilsonRS, et al.Loneliness in older black adults with human immunodeficiency virus is associated with poorer cognition. Gerontology2017; 63: 253–262.
52.
WardJBGartnerDRKeyesKM, et al.How do we assess a racial disparity in health? Distribution, interaction, and interpretation in epidemiological studies. Ann Epidemiol2019; 29: 1–7.
