Table 2.

Comparison of app-measured and actigraphy-measured circadian rhythm and sleep indicators in participants across obesity, overweight, and control groups.

Indicators				Obesity, mean (SD)		Overweight, mean (SD)		Control, mean (SD)	P value differences							Comparison
									Groupa		Measurementb		Interactionc
Sleep indicators
	Sleep onsetd								.002		.06		.09		Obe, Cf<Owg
		App	23.74 (1.01)		24.35 (1.14)		23.66 (0.83)
		Actigraphy	23.11 (0.73)		24 (1.08)		23.75 (0.85)
	Wake timed								.04		.50		.68		—h
		App	7.37 (1.27)		7.23 (1.05)		6.91 (0.8)
		Actigraphy	7.08 (0.99)		7.34 (1.18)		6.74 (0.89)
	Midpoint of sleepd								.04		.17		.39		—
		App	3.56 (1.09)		3.79 (1.05)		3.28 (0.69)
		Actigraphy	3.1 (0.7)		3.67 (1.05)		3.24 (0.82)
	Wake after sleep onset (minutes)								.76		<.001		.78		—
		App	17.5 (27)		18.4 (16.4)		14.7 (14.7)
		Actigraphy	2.4 (2.2)		4 (4.7)		3.1 (3.1)
	Total sleep time (minutes)								<.001		.003		.03		Ob>Ow, C
		App	440 (52.3)		394.3 (35.2)		420.5 (48.3)
		Actigraphy	475.8 (63)		436.5 (51.1)		416.4 (36.4)
Circadian rhythm indicators
	Interdaily stability								.001		<.001		.95		Ob<C
		App	0.17 (0.11)		0.22 (0.11)		0.25 (0.09)
		Actigraphy	0.37 (0.12)		0.42 (0.12)		0.44 (0.11)
	Intradaily variability								.54		<.001		.23		—
		App	1.3 (0.3)		1.28 (0.26)		1.22 (0.23)
		Actigraphy	0.91 (0.18)		0.81 (0.22)		0.92 (0.25)

^aThe effect of health controls versus overweight versus obesity.

^bThe effect of app versus actigraphy.

^cThe interaction of group and measurement.

^dTime are in day decimal time, for example, 23.50=23:30 PM.

^eOb: obesity group.

^fC: control group.

^gOw: overweight group.

^hNot applicable.