Table 3.

Log cortisol on awakening and after 2.5, 8, and 12 h and bed time (diurnal slope in cortisol) regressed on hours slept, sleep disturbance, hours since awakening, and potential confounders

	Model 1	Model 2	Model 3
Hours since awakening	−0.341 (0.050)	−0.265 (0.051)	−0.293 (0.053)
P value	<0.01	<0.01	<0.01
Hours since awakening squared	0.012 (0.002)	0.009 (0.002)	0.010 (0.002)
P value	<0.01	<0.01	<0.01
Sleep disturbance
Not sleep disturbed (first three quartiles)	0.000		0.000
Sleep disturbed (top quartile)	−0.011 (0.025)		0.045 (0.021)
P value	0.650		<0.05
Interaction of hours since awakening and sleep disturbance
Not sleep disturbed or at awakening	0.000		0.000
Sleep disturbed and 1 h since awakening	0.006 (0.002)		0.006 (0.002)
P value	<0.01		<0.01
Hours slept previous night
Less than 5 h		0.000	0.000
5–6 h		0.097 (0.055)	0.101 (0.060)
6–7 h		0.101 (0.050)	0.149 (0.056)
7–8 h		0.064 (0.050)	0.117 (0.056)
9+ h		−0.008 (0.055)	0.080 (0.064)
P value		<0.05	<0.01
Interaction of hours since awakening and hours slept previous night
Less than 5 h slept or at awakening		0.000	0.000
5–6 h slept and 1 h since awakening		−0.021 (0.004)	−0.020 (0.004)
6–7 h slept and 1 h since awakening		−0.027 (0.004)	−0.026 (0.004)
7–8 h slept and 1 h since awakening		−0.032 (0.004)	−0.031 (0.004)
9+ h slept and 1 h since awakening		−0.029 (0.005)	−0.028 (0.005)
P value		<0.01	<0.01

Models 1 and 2 adjusted for cortisol sample (dummy variables for whether the cortisol came from first/third/fourth/fifth/sixth sample). Model 3 additionally adjusted for age, sex, employment grade, waist circumference, smoking status, awakening time, SF-36 mental and physical component scores.