Associations of short sleep duration with prehypertension and hypertension among Lithuanian children and adolescents: a cross-sectional study

Table 2 Characteristics of the study participants according to blood pressure levels

Variables	Normotensive (n = 4504)		Prehypertensive (n = 875)		Hypertensive (n = 1561)		P*
Categorical variables^¶	n	%	n	%	n	%	P*
Sex:
Boys	1,770	39.3	475	54.3	944	60.5	<0.001
Girls	2,734	60.7	400	45.7	617	39.5
Age (years):
12–13	2,608	57.9	292	33.4	694	44.5	<0.001
14–15	1,896	42.1	583	66.6	867	55.5
Sleep duration (h/day):
≥8	3,406	75.6	529	60.5	947	60.6	<0.001
7– < 8	796	17.7	234	26.7	424	27.2
<7	302	6.7	112	12.8	190	12.2
BMI categories:
Normal weight	4,108	91.2	691	79.0	1,140	73.0	<0.001
Overweight	349	7.8	149	17.0	337	21.6
Obesity	47	1.0	35	4.0	84	5.4
Physical activity (h/day):
≥1	4,066	90.3	762	87.1	1,351	86.5	<0.001
0.5– < 1	339	7.5	85	9.7	169	10.8
<0.5	99	2.2	28	3.2	41	2.7
Smoking:
No	4,171	92.6	782	89.4	1,444	92.5	0.003
Yes	333	7.4	93	10.6	117	7.5
Continuous variables ^#	mean ± SD		mean ± SD		mean ± SD		P**
Age (years)	13.29 ± 1.09		13.89 ± 1.03^a		13.62 ± 1.09^a,b		<0.001
Weight (kg)	49.84 ± 10.15		59.54 ± 11.31^a		60.22 ± 12.66^a		<0.001
Height (cm)	162.37 ± 9.32		169.75 ± 8.87^a		168.20 ± 9.90^a,b		<0.001
BMI (kg/m²)	18.77 ± 2.76		20.59 ± 3.22^a		21.17 ± 3.50^a,b		<0.001
SBP (mmHg)	109.72 ± 6.93		124.85 ± 3.90^a		139.41 ± 9.85^a,b		<0.001
DBP (mmHg)	63.10 ± 6.38		67.22 ± 6.91^a		71.85 ± 8.08^a,b		<0.001

^¶Values are numbers and percentages.
^#Values are means ± SD (standard deviations).
BMI body mass index, SBP systolic blood pressure, DBP diastolic blood pressure.
*Significant differences between the groups were determined by the chi-squared (χ ²) test.
**Significant differences between the three groups were determined by Kruskal-Wallis test and ANOVA (data in italics).
^aSignificantly different (P < 0.05) from normotensive participants (Mann–Whitney U test; t-test).
^bSignificantly different (P < 0.05) from prehypertensive participants (Mann–Whitney U test; t-test).
^a,bSuperscript letters in bold and italics indicate that significant differences (P < 0.05) between groups were determined by the t-test.

ISSN: 1471-2458