Table 1

Clinical characteristics by current shift work exposure (n=286 825)

Current work schedule
Day workersShift work, but never or rarely night shiftsIrregular shift work including nightsPermanent night shift work
N236 89724 56018 2267142
Age, years52.90 (7.13)52.48 (7.08)51.08 (6.87)51.45 (6.91)
Sex (% male)46.5847.5162.4361.43
BMI, kg/m2 27.09 (4.65)27.79 (4.99)28.21 (4.91)28.51 (4.88)
Smoker, %
 Never58.1053.6652.8251.99
 Previous31.9132.1130.5230.03
 Current9.7513.8816.1917.67
Smoking, pack-years20.07 (16.07)22.92 (17.49)24.31 (17.77)25.70 (18.38)
Daily alcohol intake, %20.4816.8915.9810.21
Sleep duration (hours)7.05 (1.03)6.95 (1.22)6.85 (1.30)6.67 (1.52)
Morning
chronotype, %
23.3325.4922.8519.24
Evening
chronotype, %
8.027.879.8316.90
Ethnicity (%)
White British88.4783.3079.8780.99
 White other6.457.077.036.01
 Mixed0.650.900.970.87
 Asian1.723.583.843.39
 Black1.402.694.935.47
 Chinese0.340.480.460.67
 Other0.090.130.100.14
Weekly work hours34.24 (13.19)34.97 (13.21)39.29 (14.55)39.59 (13.73)
Job asthma risk (%)7.597.188.117.74
Job medical
required (%)
2.272.524.143.68
Single occupancy (%)15.6418.7818.7118.42
Urban area (%)85.9889.5989.3390.97
Townsend Index−2.24 (−3.70 to 0.19)−1.31 (−3.18 to 1.61)−1.24 (−3.17 to 1.82)−1.04 (−3.02 to 2.07)
Maternal smoking (%)26.5928.8829.2330.75
Breastfed as baby (%)56.1254.2754.1651.51
Birth weight (kg)3.33 (0.63)3.31 (0.68)3.35 (0.67)3.31 (0.71)
Hypertension (%)19.7521.5821.6422.81
High cholesterol (%)7.888.558.549.27
Sleep apnoea (%)0.280.300.420.27
COPD/
emphysema/chronic bronchitis (%)
0.811.261.271.23
Bronchiectasis (%)0.140.120.030.14
Interstitial lung
disease (%)
0.020.010.030.01
Other respiratory
problems (%)
0.120.170.160.07
Gastro-oesophageal
reflux (%)
3.193.653.844.16
  • Data are mean (SD), median (IQR) or percentages. Positive values of the Townsend Index indicate high material deprivation, negative values indicate relative affluence. The diagnosis of conditions (hypertension, high cholesterol, sleep apnoea, COPD/emphysema/chronic bronchitis, bronchiectasis, interstitial lung disease, other respiratory problems and gastro-oesophageal reflux) came from participants self-reporting a doctor diagnosis.

  • BMI, body mass index; COPD, chronic obstructive pulmonary disease.