Table 2. Characterization and methodological quality score of the studies with evidence of association between short sleep duration and high blood pressure (BP).

Author (year)	Design Location	Sample Age group	Measurement method	Sleep duration	Adjustment variables	Association between sleep duration and BP in adolescents	Score*
Paciência et al. 8 (2016)	Cross-sectional and longitudinal Portugal	n=1,403 13-17 years old	Sleep: self-reported BP: auscultatory	≤7 h > 7 h	BMI and physical activity	In the cross-sectional analysis (sleep duration and BP at 17 years old, in girls): sleep duration and SBP: β = 0.730, 95%CI 0.005-1.455)	7
Paciência et al. 22 (2013)	Cross-sectional Portugal	n=1,771 13 years old	Sleep: self-reported BP: auscultatory	≤8.5 h 8.5-9.5 h ≥9.5 h	Girls: caffeine intake, BMI and depressive symptoms. Boys: caffeine intake, playing sports	Sleep duration and elevated BP (>90 h) in girls: sleep duration 8.5-9.5 h: aOR = 1.56 (95%CI 1.07-2.27). Sleep duration ≥9.5 h: aOR =1,83 (95%CI 1.23-2.70)	8
Guo et al. 31 (2011)	Cross-sectional China	n=4,902 5-18 years old	Sleep: reported by parents BP: auscultatory	15-18 years old: <8, 8-9, ≥9 h	Age, BMI, physical activity and waist circumference	Sleep duration <8 h and hypertension (girls 15-18 years old): aOR=0.46, 95% CI 0.23-0.94, p<0.05	7

BMI: body mass index; SBP: systolic blood pressure; β: beta coefficient; 95%CI: 95% confidence interval; aOR: adjusted Odds Ratio; *methodological quality score of the studies: low quality=0 to 3; moderate quality=4 to 7 and high quality=8 to 11.