Prevalence and risk factors of hypertension based on repeated measurements in Chinese children and adolescents

Figures & data

Table I. Characteristics of participants by gender.

Items	All	Boys	Girls	T/F/χ^2
n (%)	6692	3327 (49.7%)	3365 (50.3%)
Age (mean ± SD)	10.7 ± 5.0	10.6 ± 4.3	10.7 ± 5.6	2261.155
BMI (kg/m^2) (mean ± SD)	19.1 ± 4.5	19.4 ± 4.4	18.7 ± 4.6**	47.623
Overweight n (%)	956 (14.3)	519 (15.6)	437 (13.0)**	9.328
Obesity n(%)	968 (14.5)	567 (17.0)	401(11.9)**	35.523

BMI, body mass index. **p < 0.01.

Figure 1. Results from blood pressure screening.

Table II. Mean blood pressure and prevalence at three separate visits by district.

			Mean ± SD (mmHg)		Prevalence (%)
Sex	Screening	n	SBP	DBP	Elevated SBP	Elevated DBP	HTN
All	1	6692	105 ± 13	68 ± 10	11.1	12.7	18.2
	2	866	113 ± 14	70 ± 10	4.2	2.8	5.1
	3	287	123 ± 14	75 ± 11	2.7	1.6	3.1
F/χ^2			386.129	111.368	409.889	748.248	913.383
p			< 0.001	< 0.001	< 0.001	< 0.001	< 0.001
Urban	1	3465	106 ± 13	69 ± 10	12.7	14.8	21.7
	2	591	112 ± 14	70 ± 10	5.0	3.3	6.3
	3	185	120 ± 14	74 ± 10	3.7	1.9	3.7
F/χ^2			154.428	38.102	239.7	450.4	551.3
p			< 0.001	< 0.001	< 0.001	< 0.001	< 0.001
Rural	1	3228	103 ± 12**	66 ± 9**	9.5**	10.4**	15.1**
	2	275	115 ± 14*	71 ± 11	3.3**	2.2**	4.0**
	3	102	122 ± 16*	75 ± 11*	2.2**	1.2**	2.5**
F/χ^2			223.634	73.391	172.3	301.5	367.5
p			< 0.001	< 0.001	< 0.001	< 0.001	< 0.001

*p < 0.05, **p < 0.01.

Table III. Mean blood pressure and prevalence at three separate visits by gender.

			Mean ± SD (mmHg)		Prevalence (%)
Sex	Screening	n	SBP	DBP	Elevated SBP	Elevated DBP	HTN
All	1	6692	105 ± 13	68 ± 10	11.1	12.7	18.20
	2	866	113 ± 14	70 ± 10	4.2	2.8	5.1
	3	287	123 ± 14	75 ± 11	2.7	1.6	3.1
F/χ^2			386.129	111.368	409.889	748.248	913.38
p			< 0.001	< 0.001	< 0.001	< 0.001	< 0.001
Boys	1	3327	107 ± 13	68 ± 10	12.0	12.6	19.3
	2	445	115 ± 15	71 ± 11	4.8	2.7	5.6
	3	152	126 ± 14	76 ± 10	2.9	1.6	3.3
F/χ^2			215.353	62.106	217.176	217.179	482.08
p			< 0.001	< 0.001	< 0.001	< 0.001	< 0.001
Girls	1	3365	103 ± 12*	70 ± 9	10.3*	12.8	17.1*
	2	421	110 ± 13*	70 ± 10	3.6*	2.8	4.6*
	3	135	119 ± 13*	74 ± 11	2.5*	1.5	3.0*
F/χ^2			173.107	48.401	192.460	192.460	431.013
p			< 0.001	< 0.001	< 0.001	< 0.001	< 0.001

*p < 0.05.

Figure 2. Changes in prevalence by age group at three separate visits.

Table IV. Risk factors associated with hypertension in children at three visits.

		First visit (n = 5651)			Second visit (n = 5349)			Third visit (n = 5316)
		HTN/n^a	OR (95% CI)	p	HTN/n	OR (95% CI)	p	HTN/n	OR (95% CI)	p
BMI categories^b	Normal	475/4037	1		62/3864	1		32/3859	1
	Overweight	190/797	2.64 (2.18–3.31)	0.000	44/747	3.95 (2.65–5.88)	0.000	28/740	4.54 (2.70–7.61)	0.000
	Obesity	382/817	7.07 (5.94–8.42)	0.000	165/738	17.23 (12.63–23.52)	0.000	109/717	20.63 (13.69–31.09)	0.000
Parients with HTN^c	None	891/4958	1		217/4692	1		128/4664	1
	Mother	34/148	1.27 (0.83–1.95)	0.272	13/140	1.36 (0.71–2.60)	0.348	9/137	1.48 (0.70–3.14)	0.312
	Father	109/478	1.26 (0.98–1.61)	0.067	35/451	1.35 (0.90–2.02)	0.149	29/449	1.80 (1.15–2.81)	0.010
	Both	13/67	1.28 (0.66–2.46)	0.467	6/66	1.95 (0.76–4.97)	0.163	3/66	1.39 (0.40–4.82)	0.603
Mother's education^d	Primary	36/282	1		5/270	1		4/270	1
	Secondary	610/3340	1.12 (0.75–1.68)	0.575	183/3181	2.14 (0.82–5.58)	0.118	117/3161	1.66 (0.56–4.89)	0.358
	Tertary	401/2029	1.09 (0.71–1.67)	0.706	83/1898	1.82 (0.67–4.95)	0.243	48/1885	1.27 (0.40–3.97)	0.686
Father's education	Primary	22/205	1		5/199	1		4/199	1
	Secondary	618/3344	1.48 (0.90–2.44)	0.121	185/3187	1.45 (0.55–3.86)	0.453	116/3169	1.22 (0.40–3.66)	0.728
	Tertary	407/2102	1.38 (0.82–2.33)	0.228	81/1963	1.15 (0.41–3.19)	0.792	49/1948	1.08 (0.34–3.46)	0.898
Sleep time^e	Insufficient	626/3501	1		154/3301	1		100/3284	1
	Sufficient	421/2150	1.14 (0.98–1.33)	0.084	117/2048	1.01 (0.77–1.32)	0.947	69/2032	0.85 (0.61–1.19)	0.350

Notes: HTN, hypertension, BMI, body mass index. Binary logistic regression adjusted for gender, age, puberty status, and heart rate. Puberty status was estimated by whether they have menarche for girls and whether they have spermatorrhoea for boys. ^aHTN/n, the number of HTN/the total in that group. ^bWeight status was defined according to the BMI norm for screening overweight and obesity in Chinese children and adolescents (1). ^cParents were considered to have HTN if they have been diagnosed as hypertension by doctors from upper second-class hospital or have been told by a physician or health professional that they have elevated BP and have to take antihypertensive drug regularly. ^dPrimary (lower than primary school), secondary (primary school to middle school) and tertiary (equal to or above university). ^eInsufficient sleep was defined as < 10 h/day for children aged 6–11 years, < 9 h/day for those aged 12–15 years, and < 8 h/day for those aged 16–18 years.

Figure 3. Prevalence of elevated blood pressure (BP) at three separate visits categorized by body mass index (BMI) percentile.

Lawes CM, Vander HS, Law MR, Elliott P, MacMahon S, Rodgers A. Blood pressure and the global burden of disease 2000. Part 1: Estimates of blood pressure levels. J Hypertens. 2006;24:413–422.

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