. Author manuscript; available in PMC: 2019 Nov 1.

Published in final edited form as: Aging Clin Exp Res. 2018 Sep 3;30(11):1307–1318. doi: 10.1007/s40520-018-1030-x

Table 5.

Sleep Quantity and Quality Measures in Relation to Hippocampal Volume.

Sleep Measure	Estimate^b	Std Error	p value

Sleep quantity^a
Short (<7 hours)	2.582e-5	9.386e-5	0.78
Long (>8 hours)	−8.700e-5	8.364e-5	0.30
Sleep somnolence	−1.196e-6	2.371e-6	0.62
Sleep problems index II	−7.859e-7	3.627e-6	0.83
Sleep adequacy	−1.148e-6	3.927e-6	0.77

Participants in the short sleep (<7 hours) and long sleep (>8 hours) categories are compared to participants in the optimal sleep group (7–8 hours).

Every unit increase in the sleep measure is associated with an increase or decrease (−) in units of hippocampal volume.

Note: Hippocampal volume was adjusted for intracranial volume.