rotating night shift work, sleep duration and elevated
TRANSCRIPT
Rotating night shift work, sleep duration and elevated
Gamma-glutamyl transpeptidase among steelworkers: cross-sectional
analyses from a Chinese occupational cohort
Qinglin Lia,#, Shengkui Zhanga,#, Han Wanga, Chao Xuea, Xiaohong Zhanga, Sheng
Qina, Juxiang Yuana,*
aDepartment of Epidemiology and Health Statistics, School of Public Health, North
China University of Science and Technology, Tangshan, Hebei, China
#These authors contributed equally to this work.
*Corresponding author: Tel: +13603256766; E-mail: [email protected];
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Assessment of covariates
Smoking status was divided into "never", "ever" and "current". Drinking status
was evaluated from self-reported information, mainly including the amount and
frequency of alcohol consumed per week and was divided into "never", "ever" and
"current". Those who usually consumed some alcohol at least once a week over the
past 12 months were defined as current drinkers. For current drinkers, the frequency
of drinking status (days/week), usually the average amount of alcohol consumed (g),
and types of beverages were recorded. Alcohol content across different types of
beverages in China was assessed as follows: strong spirits 53%, weak spirits 38%,
rice wine 15%, grape wine 12%, and beer 4%. Based on the beverage type, amount
consumed, and frequency, we were able to derive the amount of pure alcohol (g/week)
consumed per week.[1] Intake levels of two standard drinks (20 g ethanol daily, 140 g
weekly) daily for males and one standard drink daily (70 g weekly) for females were
considered acceptable thresholds for defining non-alcoholics.[2] In this study, we have
eliminated individuals with excessive drinking status.
Occupational hazards (high temperature, noise, dust and carbon monoxide (CO))
exposure: yes or no. Smoking and drinking status: never, ever, current. The
calculation of metabolic equivalents was based on the International Physical Activity
Questionnaire (IPAQ)[3]. Physical activity (MET- hours/week) was divided into "low",
"middle" and "high". DASH score: Score according to (dietary approaches to stop
hypertension, DASH)[4]. Height and weight were measured three times each. The
participants stood upright and barefoot in light clothes. The height and weight data
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
that were ultimately used for analysis were accurate to 0.1 cm and 0.1 kg. Body mass
index (BMI) was defined as body weight (kg) divided by the square of the body
height (m2). Blood pressure measurements were performed three times five-minute
intervals using an electronic sphygmomanometer (OMRON, HBP-1100, China), and
the participants were required to rest for more than ten minutes. Finally, the mean was
obtained for analysis. Diabetes was defined as fasting blood glucose ≥7.0 mmol/L or
if the patient was receiving hypoglycemic therapy. Elevated blood pressure was
defined as current systolic blood pressure ≥140 mmHg, or diastolic blood pressure
≥90 mmHg, or if the patient was receiving antihypertensive therapy. Total cholesterol
(TC) ≥6.22 mmol/L or low-density lipoprotein (LDL-C) ≥4.11 mmol/L or
high-density lipoprotein (HDL-C) ≤1.04 mmol/L or triglycerides (TG) ≥2.32 mmol/L,
or patients undergoing lipid-lowering therapy were considered to demonstrate
dyslipidaemia. Renal function damage: estimated glomerular filtration rate (GFR) <90
ml/min/1.73 m2 was defined as Decreased eGFR[5].
Exposure to dust was defined as workers who may be exposed to productive dust
(inorganic dust, organic dust or mixed dust) during production (GBZ/T 229.1–2010).[6]
The total dust in the air of workplace was collected at the breathing zone with a filter
membrane, and it’s concentration was calculated based on the increased weight of the
filter membrane and the amount of gas collected. When the dust concentration in the
air ≤ 50mg/m3, a filter membrane with a diameter of 37mm or 40mm was used,
otherwise a filter membrane with a diameter of 75mm would be used (GBZ/T192.1–
2007).[7] Exposure to high temperature (heat stress work) was defined as the average
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
wet-bulb globe temperature (WBGT) index of the workplace is equal or greater than
25℃in the process of production (GBZ 2.2–2007).[8] The WBGT index was measured
by black-wet bulb globe thermometer. If there was no productive heat source in the
workplace, three measuring points were selected to take the average value of WBGT
index, while where there was a productive heat source, 3 to 5 measuring points were
selected to take the average value of WBGT index. If the workplace was isolated into
different thermal or ventilated environment, 2 measuring points were selected to take
the average value of WBGT index (GBZ/T 189.7 – 2007).[9] Exposure to industrial
toxicant was defined as workers who may be exposed to a variety of harmful
chemicals (the toxicant specifically refers to carbon monoxide in this population)
during production (GBZ/T 229.2–2010).[10] Carbon monoxide or carbon dioxide in the
air of workplace was pumped into the Non-Dispersive Infrared- Ray (NDIR) analyzer
and selectively absorbs their infrared rays. The concentration of carbon monoxide was
determined according to the absorption value (GBZ/T 160.28–2004).[11] Exposure to
noise was defined as workers who exposed to a noisy environment where the 8h/d or
40h/week equivalent A-weighted sound pressure level is ≥ 80dB, which may be
harmful to health and hearing (GBZ/T 229.4 – 2012).[12] The workplace production
noise was measured by a sound level meter. If the distribution of sound field in the
workplace was uniform (between-field difference of A-sound levels were less than
3dB(A)), three measuring points were selected to take the average value, otherwise it
should be divided into several sound level areas. In each sound field, two measuring
points were selected to take the average value (GBZ/T 189.8–2007).[13]
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
data not shown
Table of contents
Table S1 The results of the differences in means of Gamma-glutamyl transpeptidase
(GGT) according to current shift status and sleep duration
Table S2 Basic characteristic of the study subjects according to Gamma-glutamyl
transpeptidase (GGT) levels
Table S3 ORs of elevated Alanine transaminase (ALT) according to different
exposure metrics of night shift work
Table S4 ORs of elevated Aspartate aminotransferase (AST) according to different
exposure metrics of night shift work
Table S5 ORs of elevated Gamma-glutamyl transpeptidase (GGT) according to
different lifestyle factors
Table S6 Joint effects of different exposure metrics of night shift work and current
drinking status on elevated Gamma-glutamyl transpeptidase (GGT)
Table S7 Joint effects of different exposure metrics of night shift work and current
smoking status on elevated Gamma-glutamyl transpeptidase (GGT)
Table S8 Joint effects of different exposure metrics of night shift work and BMI on
elevated Gamma-glutamyl transpeptidase (GGT)
Table S9 Joint effects of different exposure metrics of night shift work and physical
activity (MET- hours/week) on elevated Gamma-glutamyl transpeptidase (GGT)
Table S10 ORs of elevated GGT according to different exposure metrics of night shift
work and sleep duration without missing participants taking antiretroviral drugs
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S11 ORs of elevated GGT according to different exposure metrics of night shift
work and sleep duration after adjusted for all potential confounders
Figure S1 Duration of night shifts (years) and odds of elevated Gamma-glutamyl
transpeptidase (GGT) from restricted cubic spline models after removed the last 1%
quantile of the duration of night shifts
Figure S2 Cumulative member of night shifts (night) and odds of elevated
Gamma-glutamyl transpeptidase (GGT) from restricted cubic spline models after
removed the last 1% quantile of the cumulative member of night shifts
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S1 The results of the differences in means of Gamma-glutamyl transpeptidase (GGT)
according to current shift status and sleep duration
Characteristics Total (n=7031) GGT levels (U/L), mean P value
Current shift status, n (%) <0.001Never 1155 (16.4) 33.67Ever 1380 (19.6) 34.53Current 4496 (64.0) 34.84
Sleep duration, n (%) 0.555<7 h/day 4446 (63.2) 34.55≥7 h/day 2585 (36.8) 34.66
P-values are from rank sum test for continuous variable.
Table S2 Basic characteristic of the study subjects according to Gamma-glutamyl transpeptidase
(GGT) levels
CharacteristicsGGT levels (U/L)
P valueNormal (n=6270) Elevated (n=761)
Sex, n (%) <0.001Male 5691 (90.7) 745 (97.8)Female 579 (9.3) 16 (2.2)
Smoking status, n (%) <0.001Never 2865 (45.6) 204 (26.8)Ever 327 (5.3) 48 (6.4)Current 3078 (49.1) 509 (66.8)
Drinking status, n (%) <0.001Never 4025 (64.1) 270 (35.5)Ever 141 (2.3) 9 (1.2)Current 2104 (33.6) 482 (63.3)
Physical activity (MET-hours/week), n (%)
0.420
Low 116 (1.9) 14 (1.9)Middle 630 (10.1) 65 (8.6)High 5524 (88.0) 682 (89.5)
Sleep duration, n (%) 0.986<7 h/day 3965 (63.2) 481 (63.2)≥7 h/day 2305 (36.8) 280 (36.8)
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Diabetes, n (%) 0.957No 5594 (89.2) 676 (88.8)Yes 676 (10.8) 85 (11.2)
Elevated blood pressure, n (%) 0.699No 4536 (72.3) 556 (73.0)Yes 1734 (27.7) 205 (27.0)
Dyslipidaemia, n (%) 0.695No 3776 (60.2) 464 (60.9)Yes 2494 (39.8) 297 (39.1)
Decreased eGFR, n (%) 0.933No 5284 (84.2) 639 (83.9)Yes 986 (15.8) 122 (16.1)
BMI (kg/m2), n (%) 0.207<24 2133 (34.0) 239 (31.4)24–27 3093 (49.4) 401 (52.6)≥28 1044 (16.6) 121 (16.0)
High temperature, n (%) 0.010No 3121 (49.7) 341 (44.8)Yes 3149 (50.3) 420 (55.2)
Noise, n (%) 1.000No 48 (0.7) 5 (0.7)Yes 6222 (99.3) 756 (99.3)
Dust, n (%) 0.333No 2162 (34.4) 276 (36.2)Yes 4108 (65.6) 485 (63.8)
CO, n (%) 0.757No 3479 (55.4) 427 (56.1)Yes 2791 (44.6) 334 (43.9)
Age (years), median (range) 44.8 (46.3, 59.6) 46.3 (24.9, 60.0) <0.001Working years (years), median(range)
24.3 (0.2, 46.8) 27.2 (0.8, 42.3) <0.001
DASH Score 21.7±2.2 21.2±2.1 <0.001
Values are number of individuals (%). P-values are from chi-square test for categorical variables and rank sum test
or independent-sample T test for continuous variables. DASH, dietary approaches to stop hypertension; MET,
metabolic equivalent of task; BMI: body mass index. Decreased eGFR: decreased estimated glomerular filtration
rate.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S3 ORs of elevated Alanine transaminase (ALT) according to different exposure metrics of
night shift work
Exposure metricsTotal Model 1 Model 2 Model 3
N (%) OR (95% CI) OR (95% CI) OR (95% CI)
Current shift statusNever 1155 (16.4) 1.00 1.00 1.00Ever 1380 (19.6) 1.18 (0.85–1.48) 1.14 (0.86–1.51) 1.14 (0.86–1.51)Current 4496 (64.0) 1.49 (1.18–1.87) 1.44 (1.15–1.81) 1.44 (1.15–1.81)
Duration of night shiftsNever 1155 (16.4) 1.00 1.00 1.00≤19 years 2855 (40.6) 1.56 (1.23–1.98) 1.38 (1.09–1.76) 1.38 (1.09–1.76)>19 years 3021 (43.0) 1.25 (0.98–1.59) 1.36 (1.06–1.75) 1.36 (1.06–1.74)
P trend 0.591 0.032 0.033Cumulative number of night shifts
Never 1155 (16.4) 1.00 1.00 1.00≤1774 nights 2948 (41.9) 1.57 (1.24–1.99) 1.40 (1.10–1.78) 1.40 (1.10–1.78)>1774 nights 2928 (41.7) 1.23 (0.97–1.57) 1.34 (1.05–1.73) 1.34 (1.04–1.72)
P trend 0.704 <0.001 0.047Average frequency of night shifts
Never 1155 (16.4) 1.00 1.00 1.00≤7 nights/month 2132 (30.3) 1.17 (0.91–1.51) 1.19 (0.92–1.53) 1.19 (0.92–1.53)>7 nights/month 3744 (53.3) 1.53 (1.22–1.93) 1.48 (1.17–1.86) 1.47 (1.17–1.86)
P trend <0.001 <0.001 <0.001
Model 1: unadjusted. Model 2: adjusted for age, sex. Model 3: adjusted for age, sex, smoking status, drinking
status and DASH score. DASH, dietary approaches to stop hypertension.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S4 ORs of elevated Aspartate aminotransferase (AST) according to different exposure
metrics of night shift work
Exposure metricsTotal Model 1 Model 2 Model 3
N (%) OR (95% CI) OR (95% CI) OR (95% CI)
Current shift statusNever 1155 (16.4) 1.00 1.00 1.00Ever 1380 (19.6) 1.11 (0.69–1.78) 1.12 (0.70–1.80) 1.12 (0.70–1.80)Current 4496 (64.0) 0.95 (0.64–1.42) 0.95 (0.63–1.41) 0.95 (0.63–1.42)
Duration of night shiftsNever 1155 (16.4) 1.00 1.00 1.00≤19 years 2855 (40.6) 1.06 (0.70–1.61) 1.03 (0.67–1.58) 1.03 (0.67–1.58)>19 years 3021 (43.0) 0.92 (0.60–1.41) 0.94 (0.61–1.46) 0.95 (0.61–1.46)
P trend 0.564 0.746 0.753Cumulative number of night shifts
Never 1155 (16.4) 1.00 1.00 1.00≤1774 nights 2948 (41.9) 1.05 (0.69–1.60) 1.02 (0.66–1.56) 1.02 (0.66–1.57)>1774 nights 2928 (41.7) 0.93 (0.61–1.42) 0.95 (0.61–1.47) 0.95 (0.61–1.48)
P trend 0.595 0.788 0.790Average frequency of night shifts
Never 1155 (16.4) 1.00 1.00 1.00≤7 nights/month 2132 (30.3) 1.05 (0.68–1.63) 1.06 (0.68–1.64) 1.06 (0.68–1.64)>7 nights/month 3744 (53.3) 0.95 (0.63–1.44) 0.95 (0.63–1.43) 0.95 (0.63–1.43)
P trend 0.703 0.649 0.654
Model 1: unadjusted. Model 2: adjusted for age, sex. Model 3: adjusted for age, sex, smoking status, drinking
status and DASH score. DASH, dietary approaches to stop hypertension.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S5 ORs of elevated Gamma-glutamyl transpeptidase (GGT) according to different lifestyle
factors
Exposure metricsTotal Elevated GGT
N (%) OR (95% CI)
BMI (kg/m2), n (%)<24 2372 (33.7) 1.0024–27 3494 (49.7) 1.17(0.98–1.39)≥28 1165 (16.6) 1.07 (0.84–1.35)
Physical activity (MET- hours/week), n (%)Low and Middle 825 (11.7) 1.00High 6206 (88.3) 1.21 (0.94–1.55)
Smoking status, n (%)
Never 3069 (43.6) 1.00Ever 375 (5.3) 1.46 (1.03–2.07)Current 3587 (51.1) 1.52 (1.27–1.82)
Drinking status, n (%)Never 4295 (61.1) 1.00Ever 150 (2.1) 0.76 (0.38–1.51)Current 2586 (36.8) 2.68 (2.27–3.17)
Adjusted for age, sex, smoking status, drinking status and DASH score. DASH, dietary approaches to stop
hypertension.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S6 Joint effects of different exposure metrics of night shift work and current drinking status
on elevated Gamma-glutamyl transpeptidase (GGT)
Stratified VariablesTotal Elevated GGT
P for InteractionN (%) OR (95% CI)
Current drinking status Current shift status 0.751
NoNever 712 (16.6) 1.00Ever 833 (19.4) 1.56 (0.99–2.47)Current 2750 (64.0) 1.58 (1.06–2.35)
YesNever 419 (16.2) 1.00Ever 512 (19.8) 1.17 (0.82–1.66)Current 1655 (64.0) 1.35 (1.01–1.80)
Current drinking status Duration of night shifts 0.882
NoNever 712 (16.6) 1.00≤19 years 1905 (44.4) 1.54 (1.01–2.34)>19 years 1678 (39.0) 1.62 (1.06–2.46)
YesNever 419 (16.2) 1.00≤19 years 897 (34.7) 1.19 (0.86–1.65)>19 years 1270 (49.1) 1.38 (1.02–1.86)
Current drinking statusCumulative number ofnight shifts
0.783
NoNever 712 (16.6) 1.00≤1774 nights 1974 (46.0) 1.63 (1.07–2.47)>1774 nights 1609 (37.4) 1.52 (0.99–2.32)
YesNever 419 (16.2) 1.00≤1774 nights 920 (35.6) 1.17 (0.85–1.62)>1774 nights 1247 (48.2) 1.40 (1.03–1.90)
Current drinking statusAverage frequency ofnight shifts
0.505
NoNever 712 (16.6) 1.00≤7 nights/month 1275 (29.7) 1.54 (1.01–2.37)>7 nights/month 2308 (53.7) 1.59 (1.07–2.38)
Yes
Never 419 (16.2) 1.00
≤7 nights/month 802 (31.0) 1.29 (0.94–1.78)
>7 nights/month 1365 (52.8) 1.31 (0.97–1.77)
Adjusted for age, sex, smoking status, drinking status and DASH score. DASH, dietary approaches to stop
hypertension.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S7 Joint effects of different exposure metrics of night shift work and current smoking status
on elevated Gamma-glutamyl transpeptidase (GGT)
Stratified VariablesTotal Elevated GGT
P for InteractionN (%) OR (95% CI)
Current smoking status Current shift status 0.857
NoNever 581 (16.9) 1.00Ever 694 (20.1) 1.03 (0.65–1.64)Current 2169 (63.0) 1.31 (0.89–1.92)
YesNever 574 (16.0) 1.00Ever 686 (19.1) 1.42 (1.01–1.99)Current 2327 (64.9) 1.43 (1.07–1.91)
Current smoking status Duration of night shifts 0.278
NoNever 581 (16.9) 1.00≤19 years 1445 (42.0) 1.06 (0.70–1.62)>19 years 1418 (41.1) 1.40 (0.94–2.09)
YesNever 574 (16.0) 1.00≤19 years 1410 (39.3) 1.43 (1.04–1.96)>19 years 1603 (44.7) 1.42 (1.05–1.92)
Current smoking statusCumulative number of nightshifts
0.190
NoNever 581 (16.9) 1.00≤1774 nights 1487 (43.1) 1.05 (0.69–1.58)>1774 nights 1376 (40.0) 1.43 (0.96–2.14)
YesNever 574 (16.0) 1.00≤1774 nights 1461 (40.7) 1.47 (1.08–2.02)>1774 nights 1552 (43.3) 1.39 (1.03–1.89)
Current smoking statusAverage frequency of nightshifts
0.839
NoNever 581 (16.9) 1.00≤7 nights/month 1069 (31.0) 1.14 (0.75–1.74)>7 nights/month 1794 (52.1) 1.30 (0.88–1.92)
Yes
Never 574 (16.0) 1.00
≤7 nights/month 1063 (29.6) 1.46 (1.06–2.00)
>7 nights/month 1950 (54.4) 1.41 (1.05–1.90)
Adjusted for age, sex, smoking status, drinking status and DASH score. DASH, dietary approaches to stop
hypertension.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S8 Joint effects of different exposure metrics of night shift work and BMI on elevated
Gamma-glutamyl transpeptidase (GGT)
Stratified VariablesTotal Elevated GGT
P for InteractionN (%) OR (95% CI)
BMI Current shift status 0.297
<24Never 389 (16.4) 1.00Ever 466 (19.6) 1.09 (0.68–1.73)Current 1517 (64.0) 1.14 (0.77–1.68)
≥24Never 766 (16.4) 1.00Ever 914 (19.7) 1.38 (0.98–1.94)Current 2979 (63.9) 1.53 (1.15–2.04)
BMI Duration of night shifts 0.498
<24Never 389 (16.4) 1.00≤19 years 992 (41.8) 1.05 (0.69–1.61)>19 years 991 (41.8) 1.19 (0.79–1.79)
≥24Never 766 (16.4) 1.00≤19 years 1863 (40.0) 1.43 (1.05–1.96)>19 years 2030 (43.6) 1.54 (1.14–2.08)
BMICumulative number of nightshifts
0.586
<24Never 389 (16.4) 1.00≤1774 nights 1020 (43.0) 1.05 (0.68–1.60)>1774 nights 963 (40.6) 1.20 (0.80–1.80)
≥24Never 766 (16.4) 1.00≤1774 nights 1928 (41.4) 1.46 (1.07–2.00)>1774 nights 1965 (42.2) 1.52 (1.12–2.06)
BMIAverage frequency of nightshifts
0.953
<24Never 389 (16.4) 1.00≤7 nights/month 738 (31.1) 1.00 (0.65–1.54)>7 nights/month 1245 (52.5) 1.21 (0.81–1.79)
≥24Never 766 (16.4) 1.00≤7 nights/month 1394 (29.9) 1.55 (1.13–2.12)>7 nights/month 2499 (53.7) 1.46 (1.09–1.96)
Adjusted for age, sex, smoking status, drinking status and DASH score. DASH, dietary approaches to stop
hypertension; BMI: body mass index.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S9 Joint effects of different exposure metrics of night shift work and physical activity
(MET- hours/week) on elevated Gamma-glutamyl transpeptidase (GGT)
Stratified VariablesTotal Elevated GGT
P for InteractionN (%) OR (95% CI)
Physical activity (MET-hours/week)
Current shift status 0.655
Low and MiddleNever 137 (16.6) 1.00Ever 143 (17.3) 2.76 (1.16–6.59)Current 545 (66.1) 1.48 (0.70–3.14)
HighNever 1018 (16.4) 1.00Ever 1237 (19.9) 1.17 (0.87–1.56)Current 3951 (63.7) 1.38 (1.08–1.76)
Physical activity (MET-hours/week)
Duration of night shifts 0.698
Low and MiddleNever 137 (16.6) 1.00≤19 years 143 (17.3) 1.73 (0.77–3.87)>19 years 545 (66.1) 1.65 (0.76–3.59)
HighNever 1018 (16.4) 1.00≤19 years 1237 (19.9) 1.24 (0.95–1.62)>19 years 3951 (63.7) 1.39 (1.08–1.79)
Physical activity (MET-hours/week)
Cumulative number ofnight shifts
0.814
Low and MiddleNever 137 (16.6) 1.00≤1774 nights 143 (17.3) 1.65 (0.74–3.69)>1774 nights 545 (66.1) 1.71 (0.78–3.74)
HighNever 1018 (16.4) 1.00≤1774 nights 1237 (19.9) 1.27 (0.97–1.65)>1774 nights 3951 (63.7) 1.37 (1.06–1.77)
Physical activity (MET-hours/week)
Average frequency ofnight shifts
0.960
Low and MiddleNever 137 (16.6) 1.00≤7 nights/month 143 (17.3) 2.07 (0.92–4.66)>7 nights/month 545 (66.1) 1.51 (0.70–3.23)
HighNever 1018 (16.4) 1.00≤7 nights/month 1237 (19.9) 1.27 (0.98–1.66)>7 nights/month 3951 (63.7) 1.36 (1.06–1.74)
Adjusted for age, sex, smoking status, drinking status and DASH score. DASH, dietary approaches to stop
hypertension; MET, metabolic equivalent of task;
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S10 ORs of elevated GGT according to different exposure metrics of night shift work and
sleep duration without missing participants taking antiretroviral drugs
Exposure metricsModel 1 Model 2 Model 3
OR (95% CI) OR (95% CI) OR (95% CI)
Current shift statusNever 1.00 1.00 1.00Ever 1.29 (0.99–1.69) 1.25 (0.95–1.63) 1.27 (0.97–1.67)Current 1.39 (1.11–1.74) 1.36 (1.08–1.70) 1.37 (1.09–1.72)
Duration of night shiftsNever 1.00 1.00 1.00≤19 years 1.18 (0.92–1.49) 1.24 (0.97–1.58) 1.28 (1.00–1.65)>19 years 1.55 (1.23–1.96) 1.41 (1.11–1.78) 1.40 (1.10–1.78)
P trend <0.001 0.004 0.009Cumulative number of night shifts
Never 1.00 1.00 1.00≤1774 nights 1.18 (0.93–1.50) 1.25 (0.98–1.60) 1.30 (1.01–1.67)>1774 nights 1.55 (1.23–1.96) 1.40 (1.10–1.77) 1.38 (1.09–1.76)
P trend <0.001 0.006 0.013Average frequency of night shifts
Never 1.00 1.00 1.00
≤7 nights/month 1.36 (1.07–1.74) 1.32 (1.03–1.69) 1.34 (1.04–1.72)>7 nights/month 1.37 (1.09–1.72) 1.34 (1.06–1.69) 1.35 (1.07–1.71)
P trend 0.024 0.032 0.030Sleep duration
≥7 h/day 1.00 1.00 1.00<7 h/day 1.01 (0.86–1.79) 1.06 (0.91–1.24) 1.12 (0.96–1.32)
Model 1: unadjusted. Model 2: adjusted for age, sex. Model 3: adjusted for age, sex, smoking status, drinking
status and DASH score. DASH, dietary approaches to stop hypertension.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Table S11 ORs of elevated GGT according to different exposure metrics of night shift work and
sleep duration after adjusted for all potential confounders
Exposure metricsTotal Elevated GGT
N (%) OR (95% CI)
Current shift statusNever 1155 (16.4) 1.00Ever 1380 (19.6) 1.25 (0.95–1.65)Current 4496 (64.0) 1.35 (1.06–1.71)
Duration of night shiftsNever 1155 (16.4) 1.00≤19 years 2855 (40.6) 1.30 (1.01–1.67)>19 years 3021 (43.0) 1.34 (1.05–1.72)
P trend 0.032Cumulative number of night shifts
Never 1155 (16.4) 1.00≤1774 nights 2948 (41.9) 1.31 (1.02–1.69)>1774 nights 2928 (41.7) 1.33 (1.04–1.71)
P trend 0.044Average frequency of night shifts
Never 1155 (16.4) 1.00≤7 nights/month 2132 (30.3) 1.31 (1.02–1.69)>7 nights/month 3744 (53.3) 1.33 (1.04–1.69)
P trend 0.049Sleep duration
>5 hours 2585 (36.8) 1.00≤5 hours 4446 (63.2) 1.12 (0.96–1.33)
Adjusted for age, working age, sex, smoking status, drinking status, sleep duration, BMI, physical activity, DASH
score, dyslipidaemia, elevated blood pressure, diabetes, renal dysfunction, exposure to occupational hazards (high
temperature, noise, dust and CO) and other factors (current shift status or sleep duration). DASH, dietary
approaches to stop hypertension; MET, metabolic equivalent of task; BMI: body mass index.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Figure S1 Duration of night shifts (years) and odds of elevated Gamma-glutamyl transpeptidase
(GGT) from restricted cubic spline models after removed the last 1% quantile of the duration of
night shifts
The solid lines, the long dashes and the short dashes represent the point estimate of the OR value and the upper
and lower limits of its 95% CI, respectively. Adjusted for age, sex, smoking status, drinking status and DASH
score. DASH, dietary approaches to stop hypertension.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Figure S2 Cumulative member of night shifts (night) and odds of elevated Gamma-glutamyl
transpeptidase (GGT) from restricted cubic spline models after removed the last 1% quantile of
the cumulative member of night shifts
The solid lines, the long dashes and the short dashes represent the point estimate of the OR value and the upper
and lower limits of its 95% CI, respectively. Adjusted for age, sex, smoking status, drinking status and DASH
score. DASH, dietary approaches to stop hypertension.
REFERENCES
[1] Millwood IY, Walters RG, Mei XW, et al; China Kadoorie Biobank Collaborative
Group. Conventional and genetic evidence on alcohol and vascular disease aetiology:
a prospective study of 500 000 men and women in China. Lancet. 2019 May
4;393(10183):1831-1842. doi: 10.1016/S0140-6736(18)31772–0.
[2] Farrell GC, Chitturi S, Lau GK, et al; Asia-Pacific Working Party on NAFLD.
Guidelines for the assessment and management of non-alcoholic fatty liver disease in
the Asia-Pacific region: executive summary. J Gastroenterol Hepatol. 2007
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
Jun;22(6):775–7. doi: 10.1111/j.1440–1746.2007.05002.x.
[3] Celis–Morales CA, Perez–Bravo F, Ibanez L, et al. Objective vs. self–reported
physical activity and sedentary time: effects of measurement method on relationships
with risk biomarkers. PLoS One. 2012;7(5):e36345. doi:
10.1371/journal.pone.0036345.
[4] Maskarinec g, lim U, Jacobs s, et al. Diet quality in Midadulthood predicts visceral
adiposity and liver fatness in older ages: the Multiethnic cohort study. Obesity.
2017;25:1442–50. doi: 10.1002/oby.21868. Erratum in: Obesity (Silver Spring). 2018
Jan;26(1):239.
[5] Webster AC, Nagler EV, Morton RL, Masson P. Chronic Kidney Disease. Lancet.
2017 Mar 25;389(10075):1238–1252. doi: 10.1016/S0140–6736(16)32064–5.
[6] GBZ/T 229.1–2010 GBZ/T 229.1–2010 Classification of occupational hazards at
workplaces. Part 1: Occupational exposure to industrial dust.
http://niohp.chinacdc.cn/zyysjk/zywsbzml/201210/t20121012_70490.htm. Accessed
12 January 2021.
[7] GBZ/T 192.1–2007 Determination of dust in the air of workplace. Part 1: Total
dust concentration.
http://niohp.chinacdc.cn/zyysjk/zywsbzml/201210/t20121012_70522.htm. Accessed
12 January 2021.
[8] GBZ 2.2–2007 Occupational exposure limits for hazardous agents in the
workplace. Part 2: Physical agents.
http://niohp.chinacdc.cn/zyysjk/zywsbzml/201303/t20130329_79199.htm. Accessed
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q
12 January 2021.
[9] GBZ/T 189.7–2007 Measurement of physical agents in workplace. Part 7: Heat
Stress. http://niohp.chinacdc.cn/zyysjk/zywsbzml/201210/t20121012_70527.htm.
Accessed 12 January 2021.
[10] GBZ/T 229.2–2010 Classification of occupational hazards at workplaces. Part 2:
Occupational exposure to chemicals.
http://niohp.chinacdc.cn/zyysjk/zywsbzml/201210/t20121012_70489.htm. Accessed
12 January 2021.
[11] GBZ/T 160.28–2004 Methods for determination of inorganic carbon compounds
in the air of workplace.
http://niohp.chinacdc.cn/zyysjk/zywsbzml/201210/t20121015_70624.htm. Accessed
12 January 2021.
[12] GBZ/T 229.4–2012 Classification of occupational hazards at workplaces. Part 4:
Occupational exposure to noise.
http://niohp.chinacdc.cn/zyysjk/zywsbzml/201307/t20130715_84934.htm. Accessed
12 January 2021.
[13] GBZ/T 189.8–2007 Measurement of physical agents in workplace. Part 8: Noise.
http://niohp.chinacdc.cn/zyysjk/zywsbzml/201210/t20121012_70526.htm. Accessed
12 January 2021.
BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open
doi: 10.1136/bmjopen-2021-053125:e053125. 11 2021;BMJ Open, et al. Li Q