Table 1

Selected characteristics of Polish nurses and midwives: a cross-sectional study

CharacteristicRotating nights, (n=354)Day shifts, (n=370)p diff
Mean age (years), mean (SD)48.3 (5.2)50.2 (5.3)0.000
Menopausal status (%)
Age at menopause (in postmenopausal women) (years), mean (SD)48.5 (3.9)49.6 (4.0)0.009
Mean age at menarche (years)†, mean (SD)13.3 (1.4)13.1 (1.6)0.030
Age at first full-term birth (≥37 weeks) (years) (%)
 >24 to <303235
Number of full-term births (%)
Body mass index (kg/m2) (%)
Smoking (%)
Tea consumption (%)
Coffee consumption (%)
Physical activity (MET* hours per week), mean (SD)242 (78.4)202 (87.9)0.000
Chronotype† (%)
 Morning type51530.326
 Evening type4946
Quality of sleep PSQI (score), mean (SD)6.4 (3.0)6.9 (3.6)0.002
Current oral contraceptives or sex hormones use (%)
Drugs use grouped: β-blockers, non-steroid anti-inflammatory drugs, diuretics, antidepressives (%)
Season when urine sample collected (%)
Alcohol consumption the day before sample collection† (%)
MT6s concentrations in morning urine (ng/mg cr)
 Arithmetic mean, mean (SD)50.2 (1.7)50.9 (1.9)0.978
 Geometric mean, mean (SD)39.9 (2.2)39.7 (2.1)0.752
  • * Missing age at menarche for four women (two, rotating night shifts; two, day shift); chronotype (two, day shift); data on previous day alcohol drinking for four women (one, rotating night shift; three, day shift).