Table 5.
Descriptive analysis of the age and sex of subjects
| Age (mean ± SD) | n [Studies] | |
| All regions | ||
| ♂ | 28.5 ± 12.8 | 880 [11,18,143,145,148-150,158] |
| ♀ | 34.5 ± 17.8 | 333 [11,18,143,147-149,158] |
| Both sexes* | 41.6 ± 17.8 | 794 [11,14,17,149,151,154,157,158] |
| American Studies | ||
| ♂ | 26.0 ± 12.3 | 491 [18,143,148,150] |
| ♀ | 27.3 ± 18.9 | 127 [18,143,148] |
| Both sexes* | N/A | N/A |
| European Studies | ||
| ♂ | 27.2 ± 15.4 | 314 [11,145,149] |
| ♀ | 37.9 ± 18.9 | 191 [11,147,149] |
| Both sexes* | 42.3 ± 20.8 | 672 [11,14,15,17,151,154] |
| Australian Studies | ||
| ♂ | 42.5 | 491 [158] |
| ♀ | 45.7 | 15 [158] |
| Both sexes* | 39.5 ± 5.2 | 122 [157,158] |
| Asian Studies | ||
| ♂ | N/A | N/A |
| ♀ | N/A | N/A |
| Both sexes* | N/A | N/A |
N/A – information not available
* Both sexes refers to studies in which information on age by sex was not provided, and thus, only mean age for the whole sample was available.