Table 4.

The adjusted association between weekly work hours, extended duration shifts, and adverse safety outcomes.

			Weekly Work Hours (WWH)			Extended Duration Shifts (EDS)				Combined categorical WWH and EDS
	n cases	n person months	≤80	>80		None	1–4	≥5		≤80 WWH No EDS	≤80 WWH ≥1 EDS	>80 WWH No EDS	>80 WWH ≥1 EDS
Crashes	1,301	75,669	Ref	1.30 (1.12–1.51)	*	Ref	1.20 (0.98–1.48)	1.53 (1.27–1.86)	†	Ref	1.37 (1.13–1.64)	1.35 (1.06–1.73)	1.56 (1.27–1.92)	†
Crashes leaving work	520	75,669	Ref	1.59 (1.29–1.97)	*	Ref	1.35 (0.99–1.84)	1.91 (1.45–2.51)	†	Ref	1.45 (1.10–1.92)	1.35 (0.92–1.97)	2.20 (1.64–2.95)	†
Near-crashes	15,812	75,669	Ref	1.76 (1.67–1.87)	†	Ref	1.37 (1.27–1.48)	1.82 (1.70–1.95)	†	Ref	1.42 (1.32–1.53)	1.69 (1.52–1.88)	2.27 (2.10–2.45)	†
Occupational Exposures	5,782	78,101	Ref	1.50 (1.38–1.62)	†	Ref	1.18 (1.05–1.33)^	1.25 (1.12–1.40)^	*	Ref	1.26 (1.13–1.41)	1.67 (1.46–1.90)	1.66 (1.48–1.86)	†
Percutaneous Injuries	1,576	78,101	Ref	1.47 (1.30–1.66)	†	Ref	1.14 (0.96–1.37)^	1.19 (1.00–1.41)^		Ref	1.20 (1.01–1.43)	1.66 (1.36–2.02)	1.57 (1.32–1.87)	†
Attentional Failures	215,627	80,266	Ref	1.68 (1.63–1.73)	†	Ref	1.49 (1.42–1.56)	2.05 (1.96–2.14)	†	Ref	1.59 (1.52–1.67)	1.54 (1.46–1.63)	2.40 (2.29–2.50)	†

All models are adjusted for age, gender, BMI, specialty, and cohort. P-values are obtained from likelihood ratio tests.

^{^}Also adjusted for hours of patient care in the month.

^†p-value<0.001

^*p-value=0.001.