What works in interventions targeting loneliness: a systematic review of intervention characteristics

BMC Public Health

Table 1 Inclusion and Exclusion criteria

Inclusion criteria	Exclusion criteria
- General population*. - Loneliness is the primary intervention outcome for effectiveness. - Loneliness measured by a validated loneliness scale or self-report single item question. - English language. - Any publication period.	- Specific populations (e.g. immigrants, twins, veterans, widows)†. - Specific occupations (e.g. dentists)†. - Pre-existing conditions (e.g. chronic conditions, physical or mental health) including studies where at least half the population had low or poor health or had long-term or chronic conditions †. - Focus on related concepts such as social isolation or social connectedness. - Methodological papers, commentaries, letters, editorials, reviews, abstracts, protocols, or trial registrations. - Case studies or studies considering only one individual. - Studies evaluating the outcome of the same intervention and sample of respondents.

* Lessons can be learnt from interventions in different age groups and geographic locations, while socio-economic status should not be a limiting factor where future interventions could be provided free of charge. For these reasons, no restrictions on age, socio-economic status or geographic location were imposed for improved generalisability
† Specific populations excluded to improve generalisability and to reduce confounding from participants with specific loneliness triggers or interventions with specific adjustments for comorbidities. Studies were only excluded where explicitly evidencing a population where most (at least half) were affected by a specific health condition considered likely to require adjustments and limit generalisability to the ‘general population’

ISSN: 1471-2458