. Author manuscript; available in PMC: 2021 Jul 1.

Published in final edited form as: Psychosom Med. 2020 Jul-Aug;82(6):568–576. doi: 10.1097/PSY.0000000000000825

Table 4.

Exploratory Regression Results and Tests of Indirect Effects

Model	B	SE	p	95% CI
Total Sleep Time
SI → TST (a)	0.03751	0.01931	.053^†	−0.00044 – 0.07545
TST → diurnal cortisol slope (b)	−0.01111	0.00218	<.001^***	−0.01539 – −0.00683
SI → TST → diurnal cortisol slope (a×b)	−0.00042		.053^†	−0.00091 – 5.6x10⁻⁶
Variability in Total Sleep Time
SI → variability in TST (a)	0.00223	0.01088	.84	−0.01916 – 0.02361
Variability in TST → diurnal cortisol slope (b)	0.01116	0.00394	.005^**	0.00342 – 0.01890
Variability in Sleep Midpoint
SI → variability in SM (a)	−0.02547	0.01195	.034^*	−0.02547 – −0.00199
Variability in SM → diurnal cortisol slope (b)	0.01649	0.00353	<.001^***	0.00955 – 0.02344
SI → variability in SM → diurnal cortisol slope (a×b)	−0.00042		.042^*	−0.00095 – −0.00001
Proportion of Positive Interactions
SI → Prop. Positive Interactions (a)	0.00090	0.00138	.51	−0.00180 – 0.00361
Prop. Positive Interactions → diurnal cortisol slope (b)	−0.08853	0.03049	.004^**	−0.14846 – −0.02860

Note: Analyses included age, sex, race, and education as covariates. SI= Social Integration, TST= Total Sleep Time, SM = Sleep Midpoint. Tests of indirect effects are only reported for variables in which the a-path and b-path are both significant.

^†

An indicates p < .10

an indicates p < 0.05

^**

an indicates p < .01, and

^***

an indicates p < .001.