Table 2. Characteristics of the studies included in the general meta-analysis.
| Characteristics | n = 31 |
|---|---|
| Gender: n (%) | |
| Both | 19 (61.29) |
| Males | 6 (19.35) |
| Females | 6 (19.35) |
| Sample size: n (mean ± SE) | |
| Both | 39011 (2053.21 ± 2116.74) |
| Males | 4684 (780.67 ± 507.37) |
| Females | 7692 (1282 ± 1041.73) |
| Follow-up period ≥10 Y: n (%) | 12 (48.00) |
| Mortality: n (%) | |
| All-cause mortality | 25 (80.65) |
| Cardiovascular mortality | 4 (12.90) |
| Cancer mortality | 1 (3.23) |
| Respiratory mortality | 1 (3.23) |
| Loneliness | |
| Studies that used a single item instrument | 20 (64.52) |
| Studies that used instruments with several items | 11 (35.48) |
| Effect of loneliness on mortality: n (%) | |
| Protective (significant) | 0 |
| Null (not significant) | 18 (58.06) |
| Harmful (significant) | 13 (41.94) |
SE: Standard error; ≥10Y: Longer than ten years.