Table 4.
Comparison of clinical characteristics between those with and without vitamin D deficiency among night-shift workers.
| Characteristics | With Vitamin D Deficiency (n=133) | Without Vitamin D Deficiency (n=279) | P |
|---|---|---|---|
| Sex, male | 4 (3.0) | 21 (7.5) | .072 |
| Age*, years | 29.84 ± 8.26 | 28.63 ± 6.28 | .136 |
| PSQI, score | 8.28 ± .29 | 8.58 ± .20 | .394 |
| Self-reported poor sleep quality (PSQI > 5) | 105 (78.9) | 220 (78.9) | 1.000 |
| ESS, score | 8.38 ± .29 | 8.91 ± .20 | .137 |
| Excessive daytime sleepiness (ESS > 10) | 37 (27.8) | 87 (31.2) | .566 |
| MEQ, score | 41.31 ± .62 | 41.40 ± .43 | .910 |
| HADS, score | 13.46 ± .53 | 13.47 ± .37 | .988 |
| FSS, score | 35.47 ± .94 | 36.57 ± .65 | .338 |
| CD-RISC, score | 60.42 ± 1.20 | 61.48 ± .83 | .467 |
| QOL-BREF-physical health, score | 62.63 ± 1.37 | 61.33 ± .94 | .437 |
| QOL-BREF-psychological health, score | 60.46 ± 1.40 | 61.43 ± .96 | .570 |
| QOL-BREF-social relationship, score | 62.44 ± 1.39 | 63.40 ± .96 | .572 |
| QOL-BREF-environmental health, score | 63.60 ± 1.23 | 65.52 ± .84 | .198 |
| Actigraphy† | |||
| Sleep onset latency, min | 5.43 ± .60 | 5.97 ± .36 | .444 |
| Total sleep time, min | 410.89 ± 6.32 | 405.41 ± 3.79 | .460 |
| Sleep efficiency, % | 84.52 ± .77 | 83.91 ± .46 | .497 |
| Wake after sleep onset, min | 70.40 ± 3.95 | 71.16 ± 2.37 | .869 |
Data are presented as adjusted means ± standard error for numerical data and number (percentage) for categorized data. Analysis of covariance was performed after controlling for age and sex. *Data are presented as means ± standard deviation. †Analysis was performed for 150 night-shift workers. CD-RISC = Connor–Davidson resilience scale, ESS = Epworth Sleepiness Scale, FSS = Fatigue Severity Scale, HADS = Hospital Anxiety and Depression Scale, MEQ = Morningness–Eveningness Questionnaire, PSQI = Pittsburgh Sleep Quality Index, QOL-BREF = Quality of Life Scale Abbreviated Version.