Table 1. Socioeconomic, behavioral, and sleep characteristics of adolescents from the 1997–1998 São Luís Birth Cohort. São Luís, MA, Brazil.

Characteristic	n	%
Sex
Male	1,196	47.5
Female	1,319	52.5
Education level of the adolescent
Primary education	83	3.3
Secondary education	1,758	69.9
Higher education	672	26.8
Education level of the head of the family
Primary education	593	26.3
Secondary education	1,339	59.3
Higher education	325	14.4
CCEB
D/E	450	20.2
C	1,116	50.2
B	566	25.4
A	94	4.2
Household monthly income
≤ 1 MW	802	31.9
< 1–2.9 MW	1,085	43.1
< 3–4.9 MW	341	13.6
≥ 5 MW	287	11.4
Alcohol consumption
Low risk	2,026	80.6
High risk	489	19.4
Smoking
No	2,414	96.4
Yes	89	3.6
Use of illicit drugs
Never used	2,037	81.9
Has used or currently uses	450	18.1
Percentage of energy from sugar-sweetened beverages
< 5%	535	21.5
5–9.9%	1,093	43.8
≥ 10%	864	34.7
Caffeine intake
1st quintile	506	20.1
2nd quintile	504	20
3rd quintile	503	20
4th quintile	500	19.9
5th quintile	502	20
Screen time
< 2 hours	945	37.8
2–4.9 hours	698	27.9
≥ 5 hours	856	34.3
Physical inactivity
No	1,379	55.1
Yes	1,123	44.9
Overweight
No	1,905	75.7
Yes	610	24.3
Sleep quality (PSQI)
Good	979	46.3
Poor	1,137	53.7
Excessive daytime sleepiness (ESS)
Normal	1,586	63.2
Presence of sleepiness	924	36.8

CCEB: Brazilian Economic Classification Criterion; MW: minimum wage, PSQI: Pittsburgh Sleep Quality Index; ESS: Epworth Sleepiness Scale.