title: Risk factors for loneliness in patients with cancer: a systematic literature review and meta-analysis.
abstract: OBJECTIVE
  To systematically review the literature on the severity and risk factors for loneliness in adult cancer patients.
  
  
  METHODS
  We systematically reviewed quantitative studies addressing loneliness in cancer patients. Exclusion criteria were absence of a validated loneliness questionnaire, and studies that focused on loneliness determined by specific circumstances, and not cancer in general (e.g. appearance concerns, cultural and language barriers, requiring palliative care). We searched PsycINFO, CINAHL, Embase, Cochrane Library, and Pubmed in compliance with the predefined in- and exclusion criteria. The search, quality appraisal, and data extraction were performed by two independent reviewers. Weighted mean scores were calculated by using random effects adjusted inverse variance weighting.
  
  
  RESULTS
  We included 15 studies. In 13 studies the UCLA loneliness scale was used (range 20-80; higher scores indicate higher loneliness). The weighted mean loneliness score was 38.26 (95% CI: 35.51-41.00), which corresponds to moderate loneliness. Time since diagnosis was positively associated with degree of loneliness. Other cancer-related factors, such as cancer site, treatment type, or stage of disease were not associated with loneliness. The non-cancer related determinants of loneliness in cancer patients that emerged from our review were being unmarried (people who have never been married, are widowed or divorced), and lack of psychological or social support.
  
  
  CONCLUSIONS
  Our findings suggest that the level of loneliness rises with increasing time after cancer diagnosis. Furthermore, social functioning emerged as a consistent theme, for which it was shown that lack of social support was associated with increasing levels of loneliness.
authors.affiliation: Department of General Practice, KU Leuven, Kapucijnenvoer 33, Bus 7001, 3000 Leuven, Belgium. Electronic address: Laura.deckx@med.kuleuven.be.
authors.forename: Laura
authors.initials: L
authors.lastname: Deckx
authors.affiliation: Department of General Practice, KU Leuven, Kapucijnenvoer 33, Bus 7001, 3000 Leuven, Belgium; Department of Family Medicine, Maastricht University, CAPHRI - School for Public Health and Primary Care, Peter Debeyeplein 1, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
authors.forename: Marjan
authors.initials: M
authors.lastname: van den Akker
authors.affiliation: Department of General Practice, KU Leuven, Kapucijnenvoer 33, Bus 7001, 3000 Leuven, Belgium; Department of Family Medicine, Maastricht University, CAPHRI - School for Public Health and Primary Care, Peter Debeyeplein 1, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
authors.forename: Frank
authors.initials: F
authors.lastname: Buntinx
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008132:Loneliness / Q000523:psychology*; D008297:Male; D001523:Mental Disorders / Q000150:complications / Q000451:nursing* / Q000517:prevention & control*; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications / Q000523:psychology*; D009864:Ontario; D011788:Quality of Life; D012307:Risk Factors; D012944:Social Support; D011795:Surveys and Questionnaires
keywords: Loneliness; Meta-analysis; Neoplasms; Oncology; Risk factor; Systematic review