Table 3

Crude and adjusted logistic regression analyses showing associations among shift-related insomnia, age, gender, fraction of full position and work schedules

Day shift insomniaCrude OR†95% CIAdjusted OR‡95% CI
Age0.99(0.98 to 1.00)0.99(0.98 to 1.00)
Gender
 Male1.001.00
 Female1.02(0.68 to 1.54)1.11(0.73 to 1.69)
Fraction of full position
 50%–75%1.001.00
 76%–90%0.91(0.61 to 1.36)0.94(0.63 to 1.40)
 >90%1.45*(1.06 to 1.88)1.45*(1.08 to 1.94)
Work schedule
 Three-shift rotation1.001.00
 Permanent day0.92(0.63 to 1.35)0.88(0.59 to 1.29)
 Two-shift rotation1.08(0.83 to 1.39)1.07(0.83 to 1.39)
Evening shift insomnia
Age1.02*(1.00 to 1.03)1.01(1.00 to 1.03)
Gender
 Male1.001.00
 Female1.05(0.63 to 1.75)1.08(0.64 to 1.82)
Fraction of full position
 50%–75%1.001.00
 76%–90%1.27(0.81 to 2.00)1.24(0.78 to 1.96)
 >90%1.19(0.84 to 1.67)1.19(0.84 to 1.68)
Work schedule
 Three-shift rotation1.001.00
 Two-shift rotation1.72**(1.29 to 2.30)1.68**(1.26 to 2.24)
Night shift insomnia
Age1.00(0.98 to 1.02)1.00(0.99 to 1.02)
Gender
 Male1.001.00
 Female1.32(0.83 to 2.11)1.15(0.71 to 1.88)
Fraction of full position
 50%–75%1.001.00
 76%–90%0.87(0.56 to 1.35)0.68(0.43 to 1.08)
 >90%1.01(0.74 to 1.40)0.73(0.51 to 1.05)
Work schedule
 Three-shift rotation1.001.00
 Permanent night0.34**(0.23 to 0.51)0.30**(0.19 to 0.47)
Rest-day insomnia
Age0.99(0.97 to 1.02)0.99(0.96 to 1.03)
Gender
 Male1.001.00
 Female1.27(0.50 to 3.21)1.35(0.52 to 3.51)
Fraction of full position
 50%–75%1.001.00
 76%–90%0.52(0.23 to 1.18)0.61(0.26 to 1.39)
 >90%0.62(0.37 to 1.05)0.79(0.43 to 1.44)
Work schedule
 Three-shift rotation1.001.00
 Permanent day1.98(0.96 to 4.07)2.14*(1.02 to 4.48)
 Two-shift rotation1.19(0.64 to 2.22)1.21(0.65 to 2.25)
 Permanent night3.46**(1.76 to 6.81)3.22**(1.54 to 6.71)
  • *p<0.05; **p<0.001.

  • †OR, variables entered separately.

  • ‡OR, all variables included in the model.