Social Isolation and Incident Dementia in the Oldest-Old-A Competing Risk Analysis

Jessica Grothe; Susanne Röhr; Melanie Luppa; Alexander Pabst; Luca Kleineidam; Kathrin Heser; Angela Fuchs; Michael Pentzek; Anke Oey; Birgitt Wiese; Dagmar Lühmann; Hendrik van den Bussche; Siegfried Weyerer; Jochen Werle; Dagmar Weeg; Horst Bickel; Martin Scherer; Hans-Helmut König; André Hajek; Michael Wagner; Steffi G Riedel-Heller

doi:10.3389/fpsyt.2022.834438

Social Isolation and Incident Dementia in the Oldest-Old-A Competing Risk Analysis

Front Psychiatry. 2022 Jun 10:13:834438. doi: 10.3389/fpsyt.2022.834438. eCollection 2022.

Authors

Jessica Grothe¹, Susanne Röhr^{1

2}, Melanie Luppa¹, Alexander Pabst¹, Luca Kleineidam^{3

4}, Kathrin Heser³, Angela Fuchs⁵, Michael Pentzek⁵, Anke Oey⁶, Birgitt Wiese⁶, Dagmar Lühmann⁷, Hendrik van den Bussche⁷, Siegfried Weyerer⁸, Jochen Werle⁸, Dagmar Weeg⁹, Horst Bickel⁹, Martin Scherer⁷, Hans-Helmut König¹⁰, André Hajek¹⁰, Michael Wagner^{3

4}, Steffi G Riedel-Heller¹

Affiliations

¹ Medical Faculty, Institute of Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig, Leipzig, Germany.
² Global Brain Health Institute (GBHI), Trinity College Dublin, Dublin, Ireland.
³ Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn, Bonn, Germany.
⁴ German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
⁵ Institute of General Practice (ifam), Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
⁶ Institute of General Practice, Hannover Medical School, Hannover, Germany.
⁷ Department of Primary Medical Care, Center for Psychosocial Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
⁸ Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
⁹ Department of Psychiatry, Technical University of Munich, Munich, Germany.
¹⁰ Department of Health Economics and Health Services Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Abstract

Purpose: Social isolation is considered a risk factor for dementia. However, less is known about social isolation and dementia with respect to competing risk of death, particularly in the oldest-old, who are at highest risk for social isolation, dementia and mortality. Therefore, we aimed to examine these associations in a sample of oldest-old individuals.

Methods: Analyses were based on follow-up (FU) 5-9 of the longitudinal German study AgeCoDe/AgeQualiDe. Social isolation was assessed using the short form of the Lubben Social Network Scale (LSNS-6), with a score ≤ 12 indicating social isolation. Structured interviews were used to identify dementia cases. Competing risk analysis based on the Fine-Gray model was conducted to test the association between social isolation and incident dementia.

Results: Excluding participants with prevalent dementia, n = 1,161 individuals were included. Their mean age was 86.6 (SD = 3.1) years and 67.0% were female. The prevalence of social isolation was 34.7% at FU 5, 9.7% developed dementia and 36.0% died during a mean FU time of 4.3 (SD = 0.4) years. Adjusting for covariates and cumulative mortality risk, social isolation was not significantly associated with incident dementia; neither in the total sample (sHR: 1.07, 95%CI 0.65-1.76, p = 0.80), nor if stratified by sex (men: sHR: 0.71, 95%CI 0.28-1.83, p = 0.48; women: sHR: 1.39, 95%CI 0.77-2.51, p = 0.27).

Conclusion: In contrast to the findings of previous studies, we did not find an association between social isolation and incident dementia in the oldest-old. However, our analysis took into account the competing risk of death and the FU period was rather short. Future studies, especially with longer FU periods and more comprehensive assessment of qualitative social network characteristics (e.g., loneliness and satisfaction with social relationships) may be useful for clarification.

Keywords: competing risk analysis; epidemiology; incident dementia; longitudinal study; oldest-old; social isolation.