Table 1.
Participant Characteristics for the Entire Sample and by Shift Worker Status
| Entire sample |
Day workers |
Night workers |
||||
|---|---|---|---|---|---|---|
| (n = 392) | (n = 291) | (n = 101) | ||||
| M (SD) | M (SD) | M (SD) | p |
Cohen’s
d |
ICC | |
| Age | 39.54 (11.15) | 40.74 (11.00) | 36.12 (10.89) | <0.001 | 0.42 | |
| Baseline perceived stress | 12.19 (6.20) | 11.98 (6.16) | 12.79 (6.29) | 0.263 | 0.17 | |
| Sleep | ||||||
| Actigraphy total sleep time (min.) | 402.10 (50.37) | 408.58 (46.84) | 383.47 (55.50) | <0.001 | 0.49 | 17% |
| Actigraphy sleep efficiency (%) | 86.97 (4.87) | 87.29 (4.73) | 86.05 (5.19) | 0.027 | 0.25 | 32% |
| Self-report total sleep time (min.) | 432.21 (49.20) | 439.51 (43.62) | 411.17 (57.82) | <0.001 | 0.55 | 13% |
| Self-report sleep efficiency (%) | 91.07 (5.10) | 91.77 (4.68) | 89.04 (5.70) | <0.001 | 0.52 | 25% |
| Daily stress | 0.79 (0.60) | 0.81 (0.63) | 0.72 (0.51) | 0.196 | 0.16 | 37% |
| Total night shifts | 1.21 (2.38) | 0.00 (0.00) | 4.71 (2.34) | <0.001 | 2.85 | |
| Total day shifts | 4.85 (3.33) | 6.12 (2.72) | 1.19 (1.96) | <0.001 | 2.08 | |
| Total work shifts (day or night) | 6.06 (2.56) | 6.12 (2.72) | 5.90 (2.06) | 0.466 | 0.09 | |
| Total off days | 6.18 (2.35) | 6.02 (2.39) | 6.64 (2.16) | 0.021 | 0.28 | |
| N (%) | N (%) | N (%) | p | OR | ||
| Gender (female) | 360 (91.8) | 270 (92.8) | 90 (89.1) | <0.001 | 0.96 | |
| Ethnicity (Hispanic/Latinx) | 42 (10.8) | 26 (9.0) | 16 (15.8) | <0.001 | 1.07 | |
| Race | ||||||
| White | 305 (77.8) | 232 (79.7) | 73 (72.3) | <0.001 | 0.93 | |
| African American/Black | 26 (6.6) | 15 (5.2) | 11 (10.9) | <0.001 | 1.06 | |
| American Indian/Alaska Native | 6 (1.5) | 3 (1.0) | 3 (3.0) | <0.001 | 1.02 | |
| Asian | 41 (10.5) | 30 (10.3) | 11 (10.9) | 0.510 | 1.01 | |
| Multiracial | 7 (1.8) | 6 (2.1) | 1 (1.0) | 0.005 | 0.99 | |
| Other | 7 (1.8) | 5 (1.7) | 2 (2.0) | 0.493 | 1.00 | |
| Marital Status | ||||||
| Married | 248 (63.3) | 194 (66.7) | 54 (53.5) | <0.001 | 0.88 | |
| Single | 101 (25.8) | 63 (21.6) | 38 (37.6) | <0.001 | 1.17 | |
| Divorced | 33 (8.4) | 25 (8.6) | 8 (7.9) | 0.403 | 0.99 | |
| Separated | 7 (1.8) | 7 (2.4) | 0 (0.0) | <0.001 | 0.98 | |
| Widowed | 3 (0.8) | 2 (0.7) | 1 (1.0) | 0.229 | 1.00 |
Note. M = mean, SD = standard deviation. Cohen’s d = standardized mean difference (measure of effect size). OR = odds ratio (measure of effect size). ICC = intraclass correlation coefficient (i.e., between-person variation divided by between-person + within-person variation). Day worker = did not work any shifts between 9pm and 6am in the past two weeks (reference group); Night worker = worked at least one shift between 9pm and 6am in the past two weeks. For demographic comparisons, the group that did not identify with that characteristic is the reference group. Baseline perceived stress was assessed using the Perceived Stress Severity scale (10-item version) (Cohen, Kamarck, & Mermelstein, 1994; Cohen & Williamson, 1988).