TABLE 3.
Frequency of night shifts per month | Model 1 | Model 2 | |||
---|---|---|---|---|---|
PR | 95% CI | PR | 95% CI | ||
Irregular menstrual cycles | None | Reference | Reference | ||
1‐3 nights | 1.27 | 0.92‐1.74 | 1.28 | 0.91‐1.80 | |
4‐5 nights | 1.40 | 1.12‐1.75 | 1.41 | 1.08‐1.83 | |
≥6 nights | 1.72 | 1.34‐2.20 | 1.78 | 1.34‐2.35 | |
Amenorrhea ≥3 mo | None | Reference | Reference | ||
1‐3 nights | 0.81 | 0.26‐2.50 | 0.75 | 0.26‐2.22 | |
4‐5 nights | 1.37 | 0.70‐2.66 | 1.20 | 0.62‐2.31 | |
≥6 nights | 2.58 | 1.32‐5.03 | 2.39 | 1.27‐4.50 | |
Abnormal menstrual period | None | Reference | Reference | ||
1‐3 nights | 0.87 | 0.41‐1.86 | 0.73 | 0.33‐1.61 | |
4‐5 nights | 0.87 | 0.50‐1.49 | 0.69 | 0.38‐1.23 | |
≥6 nights | 0.97 | 0.51‐1.85 | 0.81 | 0.41‐1.60 | |
Dysmenorrhea or premenstrual symptoms affected their work | None | Reference | Reference | ||
1‐3 nights | 1.01 | 0.87‐1.18 | 1.04 | 0.88‐1.23 | |
4‐5 nights | 1.07 | 0.97‐1.19 | 1.11 | 0.98‐1.26 | |
≥6 nights | 1.04 | 0.91‐1.19 | 1.09 | 0.94‐1.27 | |
Often affected | None | Reference | Reference | ||
1‐3 nights | 1.09 | 0.63‐1.88 | 1.15 | 0.66‐2.00 | |
4‐5 nights | 1.27 | 0.88‐1.84 | 1.34 | 0.90‐2.00 | |
≥6 nights | 1.26 | 0.80‐2.00 | 1.33 | 0.81‐2.16 |
Model 1: adjusted for age. Model 2: adjusted for age, body mass index, hospital size, and the department in which the women worked.
Abbreviations: CI, confidence interval; PR, prevalence ratio.