Chronotype measures of Shift Worker Study participants according to work shift status and gender
| Chronotype measure | Day shift | Night shift | ||||||
|---|---|---|---|---|---|---|---|---|
| Female | Male | Female | Male | |||||
| N | %* | N | %† | N | %* | N | %† | |
| Smith et al‡ | ||||||||
| Evening | 3 | 2 | 5 | 3 | 26 | 15 | 12 | 7 |
| Intermediate | 125 | 82 | 114 | 73 | 124 | 73 | 155 | 86 |
| Morning | 24 | 16 | 38 | 24 | 20 | 12 | 13 | 7 |
| Trichotomous§ | ||||||||
| Evening | 15 | 10 | 22 | 14 | 62 | 36 | 48 | 26 |
| Intermediate | 84 | 55 | 76 | 48 | 70 | 41 | 93 | 51 |
| Morning | 53 | 35 | 60 | 38 | 40 | 23 | 41 | 23 |
| Dichotomous¶ | ||||||||
| Evening | 39 | 26 | 55 | 35 | 88 | 51 | 88 | 49 |
| Morning | 112 | 74 | 103 | 65 | 83 | 49 | 92 | 51 |
*Percent calculated from 152 female day shift participants and 172 female night shift participants with night-time sleep urine samples.
†Percent calculated from 158 male day shift participants and 182 male night shift participants with night-time sleep urine samples.
‡Based on chronoscore and assigned according to Smith et al: evening: 22 or less; intermediate: 23–43; morning: 44 or higher.
§Based on chronoscore and assigned as follows: evening: 28 or less; intermediate: 29–39; morning: 40 or higher.
¶Based on chronoscore and assigned as follows: evening (33 or less) or morning (34 or higher).