Table S3.
Reported light and subjective sleep (diary) by shift type
| After turning off the light/when you woke up for the day, was there any light still visible in your room? | ||||||||
|---|---|---|---|---|---|---|---|---|
| BT (mean ± SEM) | WT (mean ± SEM) | |||||||
| Yes | No | P-value (n) | Yes | No | P-value (n) | |||
| SOL (D) Day | 30.46±8.17 | 12.60±10.77 | ||||||
| Night | 22.22±7.67 | 15.26±10.78 | ||||||
| Both | 26.34±5.60 | 13.93±7.62 | 0.12 (181) | |||||
| TST (D) Day | 397.58±24.01 | 469.66±33.68 | 429.22±27.33 | 371.87±36.37 | ||||
| Night | 385.64±21.35 | 481.76±33.73 | 408.67±23.80 | 360.80±62.92 | ||||
| Both | 391.61±16.06 | 475.71±23.84 | 0.001 (163) | 418.94±18.12 | 366.33±36.34 | 0.14 (161) | ||
| WASO (D) Day | 10.45±4.19 | 6.05±5.45 | 9.33±4.28 | 8.12±5.63 | ||||
| Night | 19.05±3.93 | 10.00±5.74 | 17.46±3.87 | 7.50±9.62 | ||||
| Both | 14.75±2.87 | 8.02±3.96 | 0.10 (174) | 13.40±2.89 | 7.81±5.57 | 0.31 (172) | ||
| Qual (D) Day | 3.31±0.15 | 3.71±0.20 | 3.52±0.15 | 3.17±0.21 | ||||
| Night | 3.09±0.14 | 3.64±0.20 | 3.23±0.13 | 3.45±0.38 | ||||
| Both | 3.20±0.10 | 3.67±0.14 | <0.01 (183) | 3.37±0.10 | 3.31±0.21 | 0.76 (181) | ||
| If you answered “yes”, would you describe the light source as artificial (eg, lamp or ceiling fixture), natural (eg, sun, stars, or moon), or both? | ||||||||
| Artificial | Natural | Both | P-value (n) | Artificial | Natural | Both | P-value (n) | |
| SOL (D) Day | 30.20±11.70 | 36.80±17.04 | 20.20±23.91 | |||||
| Night | 13.93±20.14 | 23.32±11.03 | 22.69±14.29 | |||||
| Both | 22.06±11.65 | 30.06±10.15 | 21.44±13.93 | 0.82 (127) | ||||
| TST (D) Day | 399.37±35.68 | 366.23±48.59 | 452.54±66.55 | 353.58±48.10 | 470.85±36.06 | 375.65±48.32 | ||
| Night | 425.69±53.10 | 354.59±31.45 | 410.04±40.23 | NA | 408.97±27.31 | 407.89±47.86 | ||
| Both | 412.53±31.99 | 360.41±28.94 | 431.29±38.88 | 0.25 (118) | 353.58±48.10 | 439.91±22.61 | 391.77±34.00 | 0.14 (137) |
| WASO (D) Day | 12.56±6.06 | 1.84±8.72 | 18.97±12.02 | 3.88±7.41 | 10.02±5.95 | 14.00±7.80 | ||
| Night | 33.91±9.74 | 14.10±5.64 | 22.84±7.38 | NA | 19.06±4.61 | 10.24±9.06 | ||
| Both | 23.23±5.74 | 7.97±5.19 | 20.91±7.05 | 0.09 (122) | 3.88±7.41 | 14.54±3.76 | 12.12±5.98 | 0.50 (141) |
| Qual (D) Day | 3.40±0.21 | 3.13±0.30 | 3.38±0.41 | 3.32±0.25 | 3.74±0.20 | 3.38±0.26 | ||
| Night | 2.70±0.34 | 2.94±0.19 | 3.39±0.25 | NA | 3.20±0.15 | 3.33±0.28 | ||
| Both | 3.05±0.20 | 3.04±0.18 | 3.39±0.24 | 0.43 (128) | 3.32±0.25 | 3.47±0.13 | 3.35±0.19 | 0.53 (150) |
| Were you able to see objects in your room? | ||||||||
| Yes | No | P-value (n) | Yes | No | P-value (n) | |||
| SOL (D) Day | 28.79±8.24 | 12.33±12.89 | ||||||
| Night | 22.51±7.88 | 14.09±11.28 | ||||||
| Both | 25.65±5.70 | 13.21±8.57 | 0.16 (181) | |||||
| TST (D) Day | 410.93±24.49 | 447.36±43.91 | 421.45±24.47 | 371.64±63.23 | ||||
| Night | 391.89±22.40 | 463.08±36.18 | 407.99±22.42 | 361.07±79.16 | ||||
| Both | 401.41±16.59 | 455.22±28.45 | 0.08 (163) | 414.72±16.59 | 366.35±50.66 | 0.34 (162) | ||
| WASO (D) Day | 9.96±4.15 | 6.08±6.45 | 8.96±4.05 | 11.23±10.38 | ||||
| Night | 18.90±3.98 | 9.96±4.15 | 17.02±3.85 | 12.33±11.53 | ||||
| Both | 14.43±2.88 | 8.01±4.40 | 0.16 (174) | 12.99±2.80 | 11.78±7.76 | 0.87 (173) | ||
| Qual (D) Day | 3.38±0.15 | 3.59±0.24 | 3.48±0.14 | 2.75±0.40 | ||||
| Night | 3.07±0.14 | 3.73±0.21 | 3.23±0.14 | 3.57±0.45 | ||||
| Both | 3.22±0.10 | 3.66±0.16 | <0.05 (183) | 3.35±0.10 | 3.16±0.30 | 0.52 (182) | ||
| If you answered “yes”, did visible objects appear to be in shades of gray or in color (even if less vivid)? | ||||||||
| Color | Gray | P-value (n) | ||||||
| SOL (D) Day | 33.84±13.37 | 26.47±11.07 | ||||||
| Night | 11.91±10.96 | 32.63±10.99 | ||||||
| Both | 22.88±8.64 | 29.55±7.80 | 0.52 (133) | |||||
| TST (D) Day | 376.14±44.82 | 422.28±34.98 | 447.01±31.63 | 394.03±30.66 | ||||
| Night | 335.13±33.50 | 436.75±33.84 | 399.82±25.60 | 450.31±48.78 | ||||
| Both | 355.64±27.98 | 429.52±24.34 | <0.05 (124) | 423.42±20.34 | 422.17±28.81 | 0.97 (153) | ||
| WASO (D) Day | 17.79±7.49 | 5.12±6.41 | 10.58±4.52 | 6.90±4.73 | ||||
| Night | 12.96±6.22 | 24.76±6.20 | 18.58±3.98 | 10.16±7.15 | ||||
| Both | 15.38±4.87 | 14.94±4.46 | 0.94* (128) | 14.58±3.01 | 8.53±4.29 | 0.18 (163) | ||
| Qual (D) Day | 3.44±0.25 | 3.37±0.22 | 3.52±0.18 | 3.44±0.19 | ||||
| Night | 3.07±0.21 | 3.00±0.21 | 3.11±0.15 | 3.71±0.28 | ||||
| Both | 3.25±0.16 | 3.18±0.15 | 0.71 (134) | 3.32±0.12 | 3.58±0.17 | 0.14 (172) | ||
Notes: Responses to light questions and corresponding estimated marginal means of diary-based sleep variables ± SEM for each response. Responses to light questions shown by column, organized by BT and WT, and sleep variables shown in rows. SOL, WASO, TST, and Qual assessed on a scale of 1–5. Values vary slightly here from those reported in Table 3, due to inclusion here of only day and night workers (no administrator) and of shift and its interaction with response in all models. All P-values are for main effects for response only.
*
P<0.05, response–shift type interaction; Subject numbers vary slightly for each analysis.
Abbreviations: BT, bedtime; WT, wake time; SOL, sleep-onset latency; TST, total sleep time; WASO, wake after sleep onset; Qual, quality; NA, not applicable.