Table 1.

Demographics, disease characteristics, and parameters of circadian variations of melatonin secretion in controls and participants with PD.

Variable	PD	Controls	p-value	PD without EDS	PD with EDS	p-value
Demographics / Disease characteristics
N	20	15		8	12
Age	64.1±1.8	64.5±1.5	0.88	59.8±1.6	66.9±2.5	0.075
Gender	9M/11F	3M/12F	0.163*	3M/5F	6M/6F	0.67*
Education			0.58*			0.72*
College 4yrs or >	16	7		6	10
College 1–3 yrs	3	2		2	1
Grade 12 or <	1	2		0	1
Smoking status (Y/N)	1/19	1/14	1.0	1/7	0/12	0.40
Caffeine consumption (cups/day)	1.3±0.2	1.5±0.3	0.42	1.22±0.4	1.30±0.2	0.75
PD duration (yrs)	6.7±1.4			5.4±1.4	7.5±2.1	0.48
LED (mg)	436.6±70.5			378.1±87.2	475.4±103.5	0.59
UPDRS total score	34.1±2.1			30.4±2.8	36.5±2.8	0.23
UPDRS-III score	22.7±1.1			21.3±2.0	23.6±1.2	0.35
ESS score	10.9±1.1	6.1±1.0	0.006	5.6±0.8	14.3±0.9	<0.001
PSQI score	6.1±0.7	6.7±1.1	0.50	6.4±0.5	5.9±1.1	0.56
Circadian markers
Melatonin amplitude (pg/ml)	18.6±3.0	77.2±15.2	<0.001	30.2±4.6	10.8±1.6	0.001
Melatonin AUC (total)	332.7±52.4	1322.7±218.9	<0.001	574.2±81.5	189.7±20.6	0.001
Melatonin AUC (day)	161.6±20.6	490.8±72.4	<0.001	248.3±27.6	103.9±12.1	<0.001
Melatonin AUC (night)	171.1±34.3	831.9±161.0	<0.001	298.9±60.6	85.9±13.6	0.002
DLMO 2SD (CT)	6.6±0.4	7.3±0.6	0.42	6.3±0.8	6.8±0.5	0.61
DLMO 50% (CT)	15.3±0.8	14.3±0.4	0.12	15.2±0.7	15.3±1.2	0.44
DLMO 50% off (CT)	24.0±0.4	22.9±0.5	0.069	23.8±0.5	24.1±0.5	0.74
Midpoint melatonin secretion (CT)	19.8±0.4	18.6±0.4	0.074	19.5±0.5	20.1±0.7	0.56

All values are mean ± SE. p-values in this table were generated by the Kruskal-Wallis test, with the exception of the asterisked p-values that were generated by the Fisher’s exact test. LED – levodopa equivalent dose; UPDRS – Unified Parkinson Disease Rating Scale; ESS – Epworth Sleepiness Scale; PSQI – Pittsburgh Sleep Quality Index; AUC – area under curve; CT–circadian time.