Table 3

Study characteristics of the high quality studies

StudyQuality scoreStudy populationSexSample sizeParticipation rate (%)Exposure shift workersRecall/register periodOutcome measures
Prospective cohort studies
 Tüchsen et al 35 67%Danish carers of the older population: social, nursing home, home care and healthcare assistants/helpersFemale
  • N=5627:

  • 1231 evening;

  • 405 night;

  • 748 shifts

  • 3243 days

78.7%Fixed evening, fixed night, rotating shiftsRegister: 52 weeks
  1. Incidence of sick leave spells of ≥2 weeks

  2. Incidence of sick leave spells of ≥8 weeks

 Tüchsen et al 36 67%Danish working population, random sample
  • Shift workers: 49% male

  • Day workers: 52% male

  • N=5017:

  • 1008 shift workers;

  • 4009 days

75%Irregular working hoursRegister: 78 weeks
  1. Proportion of sick leave spells lasting ≥2 weeks

  2. Proportion of sick leave spells lasting ≥8 weeks

Case-control studies
 Kleiven et al 38 76%Norwegian chemical plant workersCases: 91.8% male Referents: 91.5% maleCases/references: N=3580/7582NA: Data retrieved from registers3-Shift systemRegister: 10 yearsSick spells >3 days
 Bourbonnais et al 39 59%Canadian nurses with sick leave diagnosed ‘most likely to be related to work load’Female
  • Cases/references: N=184/1165

  • Schedules:

  • 42/240 evening; 32/154 night; 46/268 shifts, 24/162 unknown; 40/341 days

NA: Data retrieved from registersFixed evening, fixed night and rotating shifts
  • Register: 3 years

  • 5 months

Sick spells ≥6 days for full-time workers, ≥8 days for part-time workers
Cross-sectional studies
 Higashi et al 40 67%Japanese chemical fibre and textile workers in production, maintenance and service departmentsMale
  • N=26 324:

  • 13 472 3-shifts;

  • 12 852 days

NA: Data retrieved from registers3-Shift systemRegister: 1 year
  1. % Spells/man/year

  2. % Number of lost work days/total normal potential work days

 Niedhammer et al 41 62%French workers, random sample from voluntarily participating occupational physicians58.2% male
  • N=24 486:

  • 3206 shifts excluding nights;

  • 1111 nights;

  • 1256 shifts including nights;

  • 18 913 days

96.5%Shift work without nights, fixed night, shift work including nightsRecall: 12 monthsProportion of workers who had at least 1 sick leave spell of >8 days
 Böckerman and Laukkanen42 54%Finnish workers from all sectors of the economy: mostly blue-collar workers58% male
  • N=725:

  • 297 shift/period workers,

  • 428 not shift/ period workers

69%Shift and period work as one groupRecall: 12 monthsProportion of workers with ≥2 sick leave days
 Ohayon et al 43 54%French psychiatric hospital staff: medical, maintenance, social services and administrative staff
  • 2-Shift: 21.4% male;

  • Fixed/rotating nights: 40.4% male

  • Fixed day: 31.9% male

  • N=817:

  • 323 2-shift;

  • 52 fixed/rotating night;

  • 442 day

40.7%2-Shift system, fixed/rotating nightsRecall: 12 monthsProportion of workers who had at least 1 sick day
 Eyal et al 44 54%Israeli shift workers in a company: industry unknownMale
  • N=519:

  • 250 shift workers; 269 white-collar workers

NA: Data retrieved from registersShift workRegister: 12 months≥20 accumulated days of registered absence