Table 1.
Clinical characteristics by current shift work exposure (n=286 825)
| Current work schedule | ||||
| Day workers | Shift work, but never or rarely night shifts | Irregular shift work including nights | Permanent night shift work | |
| N | 236 897 | 24 560 | 18 226 | 7142 |
| Age, years | 52.90 (7.13) | 52.48 (7.08) | 51.08 (6.87) | 51.45 (6.91) |
| Sex (% male) | 46.58 | 47.51 | 62.43 | 61.43 |
| BMI, kg/m2 | 27.09 (4.65) | 27.79 (4.99) | 28.21 (4.91) | 28.51 (4.88) |
| Smoker, % | ||||
| Never | 58.10 | 53.66 | 52.82 | 51.99 |
| Previous | 31.91 | 32.11 | 30.52 | 30.03 |
| Current | 9.75 | 13.88 | 16.19 | 17.67 |
| Smoking, pack-years | 20.07 (16.07) | 22.92 (17.49) | 24.31 (17.77) | 25.70 (18.38) |
| Daily alcohol intake, % | 20.48 | 16.89 | 15.98 | 10.21 |
| Sleep duration (hours) | 7.05 (1.03) | 6.95 (1.22) | 6.85 (1.30) | 6.67 (1.52) |
| Morning chronotype, % |
23.33 | 25.49 | 22.85 | 19.24 |
| Evening chronotype, % |
8.02 | 7.87 | 9.83 | 16.90 |
| Ethnicity (%) | ||||
| White British | 88.47 | 83.30 | 79.87 | 80.99 |
| White other | 6.45 | 7.07 | 7.03 | 6.01 |
| Mixed | 0.65 | 0.90 | 0.97 | 0.87 |
| Asian | 1.72 | 3.58 | 3.84 | 3.39 |
| Black | 1.40 | 2.69 | 4.93 | 5.47 |
| Chinese | 0.34 | 0.48 | 0.46 | 0.67 |
| Other | 0.09 | 0.13 | 0.10 | 0.14 |
| Weekly work hours | 34.24 (13.19) | 34.97 (13.21) | 39.29 (14.55) | 39.59 (13.73) |
| Job asthma risk (%) | 7.59 | 7.18 | 8.11 | 7.74 |
| Job medical required (%) |
2.27 | 2.52 | 4.14 | 3.68 |
| Single occupancy (%) | 15.64 | 18.78 | 18.71 | 18.42 |
| Urban area (%) | 85.98 | 89.59 | 89.33 | 90.97 |
| 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 (%) | 26.59 | 28.88 | 29.23 | 30.75 |
| Breastfed as baby (%) | 56.12 | 54.27 | 54.16 | 51.51 |
| Birth weight (kg) | 3.33 (0.63) | 3.31 (0.68) | 3.35 (0.67) | 3.31 (0.71) |
| Hypertension (%) | 19.75 | 21.58 | 21.64 | 22.81 |
| High cholesterol (%) | 7.88 | 8.55 | 8.54 | 9.27 |
| Sleep apnoea (%) | 0.28 | 0.30 | 0.42 | 0.27 |
| COPD/ emphysema/chronic bronchitis (%) |
0.81 | 1.26 | 1.27 | 1.23 |
| Bronchiectasis (%) | 0.14 | 0.12 | 0.03 | 0.14 |
| Interstitial lung disease (%) |
0.02 | 0.01 | 0.03 | 0.01 |
| Other respiratory problems (%) |
0.12 | 0.17 | 0.16 | 0.07 |
| Gastro-oesophageal reflux (%) |
3.19 | 3.65 | 3.84 | 4.16 |
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.