The impact of loneliness on mental and physical health outcomes: An umbrella review

Loneliness and related constructs associated with isolation are public health problems with increasing prevalence. The aim of this umbrella was to collate and grade evidence analyzing actual and subjective loneliness as a health risk factor. Following prospective registration, a systematic search was conducted in Pubmed, Embase, Scopus, Web of Sciences, psycoINFO and Cochrane Library until August 2023. Systematic reviews assessing the association between actual and subjective loneliness with adverse health outcomes were selected. Risk of bias was evaluated using AMSTAR-2 tool. Data were tabulated and synthesis was narrative. A total of 13 systematic reviews was selected (four included meta-analysis). The methodological quality was critically low in 10 reviews (76.92%) and low in 3 (23.08%). Results showed that loneliness was related to poor well-being and increase the risk of negative mental and physical health. The available data suggested but did not allow the confirmation of a causal association. Most constructs of loneliness seem to be related to mental and physical health conditions. A preventive strategy ought to be recommended, especially for vulnerable populations.