. Author manuscript; available in PMC: 2012 Aug 1.

Published in final edited form as: Arch Neurol. 2012 Feb;69(2):246–250. doi: 10.1001/archneurol.2011.732

Table 2.

Circadian Fluctuations in CSF Alzheimer Disease Biomarkers in 10 Patients

	Concentration by Time Point, Mean (SD), pg/mL
Biomarker Level	6 pm	12 am	6 am^a	12 pm	P Value^b
Aβ1–40	5515 (2058)	6023 (2280)	5752 (2254)	5871 (2244)	.21
Aβ1–42	443 (110)	447 (91)	437 (92)	429 (105)	.50
Total tau	78.6 (25.4)	81.3 (29.1)	80.9 (29.3)	78.5 (29.7)	.72
p-tau₁₈₁	27.0 (7.8)	28.1 (6.5)	26.4 (7.1)	28.1 (9.2)	.66

Abbreviations: CSF, cerebrospinal fluid; p-tau₁₈₁, phosphorylated tau on threonine 181.

All patients were fasting at 6 am.

Determined by repeated-measures analysis of variance.