Table 1

Baseline characteristics of participants according to their exposure to shift work and number of weekly working hours.

Shift workWorking hours (hours/week)
Day work
n=2828
Shift work
(−night work)
n=396
Shift work
(+night work)
n=115*
37
n=1689
≤27
n=436
28–36
n=455
38–44
n=381
≥45
n=453
Gender (female)50.2%49.5%56.5%41.4%93.6%85.1%29.7%22.7%
Age at exposure assessment (mean, SD)45.6 (7.1)45.1 (6.9)45.4 (7.6)45.5 (7.2)47.3 (7.0)45.4 (6.9)45.1 (7.0)44.3 (6.7)
Duration of vocational education
No education17.6%22.5%24.4%17.9%25.9%22.4%13.9%13.5%
Basic13.2%18.9%25.2%13.9%18.6%21.8%8.7%9.9%
Skilled/short38.5%32.8%33.9%42.2%30.1%27.9%34.9%39.3%
3–4 years or >4 years†30.7%25.8%16.5%26.0%25.5%27.9%42.5%37.5%
Ruminated about work‡5.8%8.6%7.9%5.2%6.9%6.6%6.6%9.1%
Had influence at work‡87.9%75.8%69.6%83.4%84.0%85.5%90.3%94.0%
Had possibilities for development‡71.7%64.4%67.8%70.0%60.3%68.5%77.2%79.8%
Smoking
Never31.3%28.5%20.9%28.8%38.3%32.1%27.0%29.6%
Previously22.3%17.2%19.1%20.1%19.3%22.6%26.3%24.3%
Yes46.4%54.3%60.0%51.2%42.4%45.3%46.7%46.1%
BMI (mean, SD)23.9 (3.4)24.6 (4.0)24.2 (3.6)24.2 (3.5)22.9 (3.5)23.1 (3.6)24.6 (3.6)24.7 (3.3)
Hypertension (yes)7.8%8.4%4.4%6.7%9.9%7.9%7.6%9.1%
Work schedule
Day work86.9%81.4%76.3%87.1%87.9%
Shift work (−night work)10.5%16.0%14.2%10.2%10.2%
Shift work (+night work)2.6%2.6%9.5%2.7%1.9%
Weekly working hours
3751.3%45.2%38.3%
≤2712.1%17.4%9.6%
28–3612.0%16.4%36.5%
38–4411.5%9.9%8.7%
≥4513.1%11.2%7.0%
  • *Three-shift workers: n=54; permanent night workers: n=61.

  • †3–4 years and >4 years are grouped together in the descriptive analyses in order to adhere to the rules regarding data confidentiality.

  • ‡Usually/always.

  • BMI, body mass index.