Table 3.

Characteristics of Latent Groups: Social Jetlag, Total Sleep Time (n=312 participants; 1,297 observations), Energy Balance Study, Columbia, SC, 2011–2014

Variable	Social Jet Lag (h)		p-value1	Total Sleep Time (h)			p-value1
	Low	High		Short	Intermediate	Long
	(0.4±0.04)2	(1.4±0.03)2		(5.6±0.04)2	(6.5±0.02)2	(7.3±0.03)2
	%	%		%	%	%
Sex
Male	55	48	0.20	71*	54	35*	<0.01
Female	45	52		29*	46	65*
Race
European American	64	68		27*	71	82
African American	12	10	0.50	30*	9	2	<0.01
Other3	24	22		43*	20	16
Employment
Student/Other4	52	41	0.05	50	46	43	0.70
Employed	48	59		50	54	57
Income ($)
< 20,000	19	16		24*	16	16
20,000 to < 40,000	36	38		43*	38	30
40,000 to < 60,000	19	19	0.80	23*	21	16	0.02
60,000 to < 80,000	13	14		4*	16	16
≥ 80,000	13	13		6*	9	22
Marital status
Married5	46	46	0.96	70*	50	50	0.02
Single6	54	54		30*	50	50
Children
Yes	17	11	0.10	13	18	8*	0.10
No	83	89		87	82	92*
	Mean±SE	Mean±SE		Mean±SE	Mean±SE	Mean±SE
Chronotype (h)	3.8±0.1	4.3±0.05	0.01	4.6±0.1*	4.1±0.1	3.9±0.05	<0.01
Age (yrs)	27.8±0.2	27.6±0.1	0.30	27.0±0.2*	28.0±0.2	27.7±0.2	<0.01
Physical activity (h/d)	2.2±0.1	2.2±0.1	1.00	2.3±0.2	2.3±1.0	2.0±0.1*	0.04
Caffeine (g/d)	109.0±8.6	117.4±6.8	0.50	79.3±11.7*	120.2±7.9	126.5±8.8	<0.01
E-DII	0.4±0.2	0.6±0.1	0.40	1.1±0.2*	0.4±0.1	0.3±0.2	0.01
BMI (kg/m2)	25.3±0.3	25.3±0.3	0.94	26.0±0.5	25.2±.3	24.9±0.4	0.22

¹Overall F-test p-value for variable of interest.

²Mean±SE in parentheses.

³Hispanic/Latino, Asian, Native American, mixed race.

⁴Out of work (<1 year), homemaker, unable to work.

⁵Includes members of unmarried couples.

⁶Includes divorced and separated.

^*p<0.05 versus intermediate group.

Abbreviations: SE - standard error, E-DII - energy-adjusted Dietary Inflammatory Index.