Table 1. Demographic and clinical characteristics of the participants.
| Characteristics | 2011 (n = 37,653) | 2012 (n = 38,147) | 2013 (n = 36,509) | 2014 (n = 36,322) | 2015 (n = 35,033) | |
|---|---|---|---|---|---|---|
| Age | 15.1 ± 0.0 | 15.0 ± 0.0 | 15.0 ± 0.0 | 15.0 ± 0.0 | 15.1 ± 0.0 | |
| Pubertal timing grade | 9.1 ± 0.0 | 9.1 ± 0.0 | 9.1 ± 0.0 | 9.0 ± 0.2 | 9.0 ± 0.2 | |
| Pubertal timing group | ||||||
| Group 1 | 6,099 (16.2) | 5,971 (15.4) | 5,721 (15.6) | 5,746 (15.7) | 5,562 (15.6) | |
| Group 2 | 5,924 (15.8) | 5,665 (14.8) | 5,289 (14.5) | 4,998 (13.8) | 4,819 (13.7) | |
| Group 3 | 8,339 (22.5) | 7,899 (21.2) | 7,046 (19.8) | 6,720 (19.0) | 6,136 (18.4) | |
| Group 4 | 17,291 (45.5) | 18,612 (48.5) | 18,453 (50.2) | 18,858 (51.5) | 18,516 (52.3) | |
| Perceived stress (high) | 13,547 (35.8) | 13,340 (34.8) | 12,501 (34.3) | 11,124 (30.8) | 10,285 (29.6) | |
| Depressive symptoms (yes) | 10,607 (28.0) | 9,722 (25.5) | 9,193 (25.2) | 7,996 (22.2) | 6,806 (19.7) | |
| Suicidal ideation (yes) | 5,756 (15.4) | 5,332 (14.1) | 4,770 (13.1) | 3,968 (11.0) | 3,311 (9.6) | |
| Suicide attempt (yes) | 1,167 (3.0) | 1,062 (2.8) | 1,065 (2.8) | 839 (2.3) | 679 (2.0) | |
Data are presented as mean ± standard deviation or number (%). The participants were divided into four groups based on the average grade at spermarche: group 1 (spermarche occurred earlier than the average grade), group 2 (average), group 3 (spermarche occurred later than the average grade), and group 4 (had not yet experienced spermarche).