. Author manuscript; available in PMC: 2017 Sep 5.

Published in final edited form as: J Biol Rhythms. 2017 Jan 16;32(1):64–74. doi: 10.1177/0748730416685451

Table 1.

Cox proportional hazards models for NREM/REM sleep cycle duration, NREM sleep episode duration, and REM sleep episode duration with covariates age, subject, and time since lights-off.

		3Y Compared with 2Y	5Y Compared with 2Y	Time Since Lights-off (h)
NREM/REM sleep cycle duration	Hazard coefficient	−0.278	−0.661	0.043
	Standard error	0.185	0.196	0.031
	p value	0.13	0	0.17
NREM sleep episode duration	Hazard coefficient	−0.31	−0.758	0.21
	Standard error	0.177	0.188	0.026
	p value	0.08	<0.01	<0.01
REM sleep episode duration	Hazard coefficient	−0.025	−0.231	−0.153
	Standard error	0.191	0.201	0.038
	p value	0.90	0.25	<0.01

Negative coefficients indicate longer durations.