Table 1 Basic characteristics of 505 study participants by interval time
From: Relationship between menstruation status and work conditions in Japan
| Number (%) or median (25–75% range) |
Less than 11 h of interval time (n = 37) |
11 h and more interval time (n = 468) | p-valuesa | ||
|---|---|---|---|---|---|
| Age (years) | 29 (25–38) | 33 (29–38) | 0.0101 | ||
| Smoking (yes) | 1 (3%) | 19 (4%) | 0.684 | ||
| Body mass index (kg/m2) | 19.9 (19.4–22.3) | 19.8 (18.6–21.2) | 0.1614 | ||
| Insufficient breakfast (not a well-balanced breakfast or not every morning) | 18 (49%) | 264 (56%) | 0.360 | ||
| Parity (yes) | 5 (14%) | 155 (33%) | 0.014 | ||
| Family care demands (yes) | 12 (32%) | 265 (57%) | 0.004 | ||
| Living situation (alone) | 10 (27%) | 116 (25%) | 0.762 | ||
| Marital status (married) | 9 (24%) | 249 (53%) | 0.001 | ||
| Living with children (yes) | 5 (14%) | 161 (34%) | 0.009 | ||
| Satisfaction with present social status (Satisfied) | 31 (84%) | 383 (82%) | 0.767 | ||
| Education (graduate school) | 12 (32%) | 168 (36%) | 0.672 | ||
| Regular employment (yes) | 32 (86%) | 315 (67%) | 0.015 | ||
| Subjective economic conditions (Upper & Upper middle) | 17 (46%) | 177 (38%) | 0.328 | ||
| Length of time in present status (years) | 3.9 (2.7–10.7) | 6.7 (3.2–11.8) | 0.1634 | ||
| Occupations: | Clerical and related workers | 13 (35%) | 177 (38%) | 0.213 | |
| Professional and highly technical job | 6 (16%) | 133 (28%) | |||
| Teachers at school | 12 (32%) | 95 (20%) | |||
| Others | 6 (16%) | 63 (13%) | |||
| Average interval time (hours/day) | 9.5 (8.4–10.3) | 14.3 (12.8–16.4) | <0.0001 | ||
| Average regular work time (hours/month) | 250 (240–280) | 170 (140–200) | <0.0001 | ||
| Average extra work time (hours/month) | 50 (40–90) | 11 (0–34) | <0.0001 | ||
| Average commuting time (hours/day) | 1 (1–2) | 1 (0–2) | 0.0023 | ||