Table S1. Demographic Variables for Subjects with Missing Data
Table S1. Demographic variables for subjects with missing data
Day workers(n=139) / Rotating shift workers
(n=224)
# missing / # missing
Age (yr) / 42.4±9.5 / 24 / 40.4±11.1 / 27
Sex / 13 / 35
Male / 3 (2.4) / 10 (5.3)
Female / 123 (97.6) / 179 (94.7)
Experience as a nurse (yrs) / 16.7±9.3 / 12 / 15.1±9.7 / 18
Experience as a rotating shift worker (yrs) / 9.3±7.4 / 21 / 12.4±8.6 / 25
The number of night shifts (days) / 0 / 0 / 5.7±2.7 / 52
Position / 0 / 0
Staff / 106 (76.3) / 174 (77.7)
Senior staff / 13 (9.4) / 35 (15.6)
Department director / 18 (13.0) / 13 (5.8)
Other / 2 (1.4) / 2 (0.9)
Marital status / 0 / 0
Married / 110 (79.1) / 109 (48.7)
Unmarried/Divorced / 29 (20.9) / 115 (51.3)
Habitual drinker1,2 / 20 (15.0) / 6 / 35 (16.5) / 12
Habitual smoker1,3 / 28 (22.2) / 13 / 80 (39.4) / 21
Habitual physical activity (METs-h/week) / 32.9±55.4 / 72 / 39.5±56.6 / 85
CES-D score / 13.7±8.0 / 0 / 14.3±7.3 / 0
CES-D score ≥ 16 / 47 (33.8) / 0 / 79 (35.3) / 0
Habitual sleep duration
Nights between day shifts (mins) / 374±67 / 0 / 354±69 / 0
Nights between days off (mins) / 443±84 / 22 / 446±97 / 1
MEQ score / 56.9±6.9 / 0 / 53.2±6.9 / 0
Chronotype / 0 / 0
Morning / 56 (40.3) / 47 (21.0)
Intermediate / 83 (59.7) / 168 (75.0)
Evening / 0 (0.0) / 9 (4.0)
Values are means ± SD or number (%). CES-D: Center for Epidemiologic Studies Depression scale; MEQ: Morningness-Eveningness Questionnaire.
1Based on National Health and Nutrition Examination Survey definition.
2Drinks more than 22 g of alcohol per day more than three times per week.
3Smoked for more than six months or a total of 100 cigarettes.
Table S2. Coefficients of the MEQ score, sleep duration on day shifts, rotating shift work, and interaction effects of rotating shift work on the CES-D score in multivariate linear regression adjusted with sample weights for imputed data sets (n = 3032)
Independent variable / Unstandardized coefficient(SE) / 95% CI of unstandardized coefficient / Standardizedcoefficient / Partial correlation
coefficient / P value
Lower / Upper
Crude
MEQ score / −0.249 (0.028) / −0.305 / −0.194 / −0.236 / < 0.001
Sleep duration / −0.019 (0.003) / −0.026 / −0.013 / −0.163 / < 0.001
Rotating shift work / 1.037 (0.384) / 0.284 / 1.789 / 0.066 / 0.007
Model 12
MEQ score / −0.248 (0.028) / −0.302 / −0.193 / −0.234 / −0.227 / < 0.001
Rotating shift work / −0.108 (0.351) / −0.580 / 0.796 / −0.007 / −0.007 / 0.758
Model 21,3
MEQ score / −0.185 (0.029) / −0.243 / −0.128 / −0.175 / −0.153 / < 0.001
Sleep duration / −0.013 (0.004) / −0.020 / −0.006 / −0.108 / −0.099 / < 0.001
Rotating shift work / −0.031 (0.629) / −1.263 / 1.202 / −0.002 / −0.001 / 0.961
Model 31,4
MEQ score / −0.149 (0.033) / −0.213 / −0.084 / −0.141 / −0.106 / < 0.001
Sleep duration / −0.013 (0.005) / −0.022 / −0.004 / −0.114 / −0.069 / 0.003
Rotating shift work / −0.115 (0.630) / −1.350 / 1.120 / −0.007 / −0.004 / 0.855
MEQ score Rotating shift work / 0.087 (0.057) / −0.024 / 0.198 / 0.051 / −0.024 / 0.126
Sleep duration Rotating shift work / −0.001 (0.006) / −0.013 / 0.011 / −0.004 / −0.002 / 0.905
1Adjusted by age, sex, years of experience as a rotating shift worker, the number of night shifts during the previous 1 month, position, marital status, drinking habits, smoking habits,physical activity level, and sleep duration on days off.
2F(2, 3027.0) = 40.06, p < 0.001, adjusted R2=0.0556.
3F(15, 3010.6) = 9.40, p < 0.001, adjusted R2=0.0838.
4F(17, 3009.6) = 8.46, p < 0.001, adjusted R2=0.0853.
SE: standard error; CI: confidence interval.
Table S3. Coefficientsof the MEQ score and sleep duration on day shiftson the CES-D score in multivariate linear regression adjusted with sample weights for imputed data sets in day workers and rotating shift workers
Independent variable / Unstandardized coefficient(SE) / 95% CI of unstandardized coefficient / Standardizedcoefficient / Partial correlation
coefficient / P value
Lower / Upper
Day workers
(n = 1252)
Model 41
MEQ score / −0.244 (0.051) / −0.344 / −0.144 / −0.223 / −0.209 / < 0.001
Sleep duration / −0.011 (0.005) / −0.021 / −0.001 / −0.093 / −0.080 / 0.039
Rotating shift workers
(n = 1780)
Model 42
MEQ score / −0.148 (0.033) / −0.213 / −0.082 / −0.136 / −0.119 / < 0.001
Sleep duration / −0.014 (0.005) / −0.024 / −0.005 / −0.117 / −0.109 / 0.003
Adjusted by age, sex, years of experience as a rotating shift worker, the number of night shifts during the previous 1 month, position, marital status, drinking habits, smoking habits, physical activity level, and sleep duration on days off.
1F(13, 1235.6) = 6.22, p < 0.001, adjusted R2=0.1012.
2F(14, 1761.0) = 5.86, p < 0.001, adjusted R2=0.0733.