title: Social relationships and risk of dementia: A systematic review and meta-analysis of longitudinal cohort studies.
abstract: It is unclear to what extent poor social relationships are related to the development of dementia. A comprehensive systematic literature search identified 19 longitudinal cohort studies investigating the association between various social relationship factors and incident dementia in the general population. Relative risks (RRs) with 95% confidence intervals (CIs) were pooled using random-effects meta-analysis. Low social participation (RR: 1.41 (95% CI: 1.13-1.75)), less frequent social contact (RR: 1.57 (95% CI: 1.32-1.85)), and more loneliness (RR: 1.58 (95% CI: 1.19-2.09)) were statistically significant associated with incident dementia. The results of the association between social network size and dementia were inconsistent. No statistically significant association was found for low satisfaction with social network and the onset of dementia (RR: 1.25 (95% CI: 0.96-1.62). We conclude that social relationship factors that represent a lack of social interaction are associated with incident dementia. The strength of the associations between poor social interaction and incident dementia is comparable with other well-established risk factors for dementia, including low education attainment, physical inactivity, and late-life depression.
authors.affiliation: Department of Epidemiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. Electronic address: j.s.kuiper@umcg.nl.
authors.forename: Jisca S
authors.initials: JS
authors.lastname: Kuiper
authors.affiliation: Department of Psychiatry, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. Electronic address: m.zuidersma@umcg.nl.
authors.forename: Marij
authors.initials: M
authors.lastname: Zuidersma
authors.affiliation: Department of Psychiatry, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. Electronic address: r.c.oude.voshaar@umcg.nl.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Oude Voshaar
authors.affiliation: Department of General Practice, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Postbus 196, HPC FA21, 9700 AD Groningen, The Netherlands. Electronic address: s.u.zuidema@umcg.nl.
authors.forename: Sytse U
authors.initials: SU
authors.lastname: Zuidema
authors.affiliation: Department of Epidemiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands; Department of Mathematics and Computer Science, Eindhoven University of Technology, Postbus 513, 5600 MB, Eindhoven, The Netherlands. Electronic address: e.r.v.d.heuvel@tue.nl.
authors.forename: Edwin R
authors.initials: ER
authors.lastname: van den Heuvel
authors.affiliation: Department of Epidemiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. Electronic address: r.p.stolk@umcg.nl.
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Stolk
authors.affiliation: Department of Epidemiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. Electronic address: n.smidt@umcg.nl.
authors.forename: Nynke
authors.initials: N
authors.lastname: Smidt
mesh_terms: D000375:Aging / Q000523:psychology*; D003704:Dementia / Q000453:epidemiology / Q000523:psychology; D006801:Humans; D007398:Interpersonal Relations; D008137:Longitudinal Studies; D018570:Risk Assessment; D012307:Risk Factors; D012931:Social Environment; D058992:Social Participation / Q000523:psychology*; D012944:Social Support
keywords: Dementia; Loneliness; Social contact; Social network; Social participation; Social relationships