Social, Biological and Behavioral Factors Associated with Social Jet Lag and Sleep Duration in University Students from a Low Urbanized City

Figures & data

Table 1 Descriptive Analysis of Variables Classified as Social and Biological Factors. Santa Cruz/ RN. Brazil, 2021

Social and Biological Factors	N	%
Socioeconomic class
Class A	11	3.7
Class B	95	31.9
Class C	156	52.3
Class D e E	36	12.1
Work
No	273	91.6
Yes	25	8.4
Knowledge about sleep
≤ 13 hits	156	52.3
≥ 14 hits	142	47.7
Start time of classes
Irregular schedules	124	42.5
Between 7:00 am to 7:49 am	57	19.5
Between 7:50 to 8:55h am	110	37.7
Daily commute
No	281	94.6
Yes	16	5.4
Perception of sleeping place
Good	274	91.9
Poor	24	8.1
Sex
Male	80	26.8
Female	218	73.2
Health problem in the previous month
No	169	56.7
Yes	129	43.3
Age
≤ 25 years	270	90.6
> 25 years	28	9.4
Sleep duration in the week
≤ 6 hours	128	43.0
> 6 hours	170	57.0
Sleep duration in the weekend
≤ 6 hours	23	7.7
> 6 hours	275	92.3
Social Jet lag
< 1 hour	102	34.3
1 to 2 hours	156	52.3
> 2 hours	40	13.4

Table 2 Descriptive Analysis of Behavioral Factors. Santa Cruz/RN. Brazil. 2021

Behavioral Factors
	Yes	No
Physical activity	155 (52%)	143 (48%)
Behavioral factors related to bedtime	Yes	No
Being a smoker	6 (2%)	292(98%)
Consume stimulating drinks	58(19.5%)	240(80.5%)
Consume alcoholic beverages	19 (6.4%)	279(93.6%)
Eat inadequate food	107(35.9%)	191(64.1%)
Academic demand
Week	227(76.2%)	71 (23.8%)
Weekend	207(69.5%)	91 (30.5%)
Use electronic devices
Week	277(76.2%)	71 (23.8%)
Weekend	259(86.9%)	39 (13.1%)
Leisure activities
Week	80 (26.8%)	218(73.2%)
Weekend	85 (28.5%)	213(71.5%)
Household chores
Week	62 (20.8%)	236(79.2%)
Weekend	226(75.8%)	72 (24.2%)
Behavioral factors related to wake up time	Yes	No
Academic demand
Week	250(83.9%)	48 (16.1%)
Weekend	69 (23.2%)	229(76.8%)
Household chores
Week	61 (20.5%)	237(79.5%)
Weekend	93 (31.2%)	205(68.8%)
Recreational and religious activities
Week	43(14.4%)	255(85.6%)
Weekend	88(29.5%)	210(70.5%)

Table 3 Multiple Linear Regression Analysis of Variables Associated with Social Jet Lag in University Students. Santa Cruz/RN. Brazil, 2021

Model I – Outcome: Social Jet Lag (Minutes)	B^a	t	p	IC 95%^b
Variables
Leisure activities in the weekend	23.24	3.90	0.001*	11.52 to 34.95
Academic demand before bedtime in the weekend	19.51	3.36	0.001*	8.09 to 30.92
Household chores before bedtime in the week	17.61	2.60	0.010*	4.32 to 30.89
Consuming stimulant drinks	− 15.17	−2.21	0.028*	−28.67 to −1.67

Notes: Parameters of Multiple regression – Social Jet lag (Constant of model B = 47.45; F= 10.96; p<0.001; R² =0.126) ^aUnstandardized Coefficients ^bConfidence Interval. *p-value <0.05. Social Jet lag was expressed in minutes.

Table 4 Multiple Linear Regression Analysis of Variables Associated with Duration of Sleep in the Week and in the Weekend in University Students. Santa Cruz/RN. Brazil, 2021

Variables	B^a	t^b	p	IC 95%
Model II - Outcome: Duration of sleep in the week (minutes)
Male (sex)	−26.51	−2.92	0.004*	−44.36 to −8.67
Chronotype	−0.56	−11.74	<0.001*	−0.65 to −0.47
Leisure activities before bedtime in the weekend	−27.63	−3.080	0.002*	−45.29 to −9.97
Poor perception about sleeping place	−43.02	−2.917	0.004*	−72.05 to −13.99
Daily Commute	−68.97	−3.86	<0.001*	−104.13 to −33.82
Model III – Outcome: Duration of sleep in the weekend (minutes)
Male (sex)	−36.36	−3.31	0.001*	−57.97 to −14.76
Chronotype	0.25	4.31	<0.001*	0.13 to 0.36
Poor perception about sleeping place	−58.16	−3.21	0.001*	−93.78 to −22.54
Recreational and religious activities upon waking	−31.11	−2.22	0.027*	−58.65 to −3.58
Leisure activities before bedtime in the weekend	−25.10	−2.32	0.021	−46.44 to −3.76
Academic demand before bedtime	−23.60	−2.25	0.025	−44.23 to −2.97

Notes: ^aUnstandardized Coefficients ^bConfidence Interval. *p-value <0.05. Parameters of Multiple regression - Duration of sleep in the week (Constant of model B = 644.01; F=40,52; p<0.001; R²=0.414). Parameters of Multiple regression - Duration of sleep in the weekend (Constant of model B = 402.31; F=9,56; p<0.001; R²=0.168).