Table 1.
Quality assessment and socioeconomic variables analyzed of the observational studies included in the systematic review.
| Quality | Socioeconomic Variables Analyzed | |
|---|---|---|
| Bardon et al., 2018 [19] | Medium | Educational level, living alone, marital status |
| Boulos et al., 2016 [17] | High | Feeling of loneliness |
| Cabrera et al., 2007 [18] | Medium | Educational level |
| Chen et al., 2007 [16] | Medium | Educational level, marital status, income level |
| Damayanthi et al., 2018 [29] | High | Educational level, living alone, marital status, income level |
| Debnath et al., 2017 [44] | Medium | Educational level, living alone, marital status, income level, occupational level |
| Donini et al., 2013 [14] | Medium | Educational level, living alone, marital status, income level, occupational level |
| El Zoghbi et al., 2014 [20] | Medium | Educational level, income level |
| El-Desouky et al., 2018 [45] | High | Educational level, living alone, marital status, income level, occupational level |
| Eskelinen et al., 2016 [21] | Medium | Living alone, feeling of loneliness |
| Farre et al., 2014 [26] | High | Educational level, living alone, marital status |
| Ferdous et al., 2009 [41] | High | Educational level, marital status, income level, food expenditure |
| Ferra et al., 2012 [22] | High | Educational level, living alone, income level |
| Fjell et al., 2018 [23] | Medium | Marital status |
| Gündüz et al., 2015 [52] | Medium | Educational level, living alone, marital status |
| Jésus et al., 2017 [46] | High | Educational level, marital status, occupational level |
| Ji et al., 2012 [37] | Medium | Educational level, living alone, income level, occupational level |
| Johansson et al., 2009 [40] | Medium | Living alone |
| Jun et al., 2016 [51] | High | Educational level, living alone, marital status, income level, occupational level, place of residence |
| Krzymińska-Siemaszko et al., 2014 [39] | Medium | Educational level, living alone, marital status, income level, place of residence |
| Lengyel et al., 2017 [50] | Medium | Living alone |
| Lin et al., 2016 [53] | High | Educational level, living alone, marital status, occupational level |
| Madeira et al., 2018 [24] | High | Educational level, marital status, income level |
| Maseda et al., 2017 [13] | Medium | Educational level, living alone, marital status, feeling of loneliness |
| Mathew et al., 2017 [42] | Medium | Educational level, living alone, marital status, income level |
| Mitri et al., 2016 [25] | High | Educational level, living alone, income level |
| Mokhber et al., 2011 [28] | Low | Educational level, living alone, occupational level, place of residence |
| Naidoo et al., 2015 [43] | High | Educational level, living alone, income level |
| Olayiwola et al., 2006 [47] | Medium | Educational level, income level |
| Park et al., 2014 [27] | Medium | Educational level, living alone, marital status, income level |
| Ramage-Morin et al., 2013 [49] | Medium | Educational level, living alone |
| Rodriguez-Tadeo et al., 2011 [32] | Medium | Living alone |
| Romero-Ortuno et al., 2010 [31] | Medium | Living alone |
| Schilp et al., 2011 [33] | High | Educational level, marital status, income level, loneliness feeling |
| Shi et al., 2014 [30] | High | Educational level, marital status, income level, occupational level |
| Söderhamn et al., 2012 [34] | Medium | Marital status, occupational level, feeling of loneliness |
| Suzana et al., 2013 [36] | Medium | Educational level, living alone, marital status, occupational level, feeling of loneliness |
| Timpini et al., 2011 [35] | Medium | Educational level, marital status, income level, occupational level |
| Westergren et al., 2014 [38] | High | Living alone |
| Wham et al., 2015 [48] | High | Educational level, living alone, marital status |