Eur J Nutr DOI 10.1007/s00394-013-0571-1
ORIGINAL CONTRIBUTION
Comparison of blood pressure levels among children and adolescents with different body mass index and waist circumference: study in a large sample in Shandong, China Ying-Xiu Zhang • Shu-Rong Wang
Received: 28 April 2013 / Accepted: 26 July 2013 Ó Springer-Verlag Berlin Heidelberg 2013
Abstract Purpose Several anthropometric indicators [such as body mass index (BMI), waist circumference (WC), and waistto-height ratio (WHtR)] have been used to investigate the association between adiposity and high blood pressure (BP) in both adults and children. The present study compared the BP levels among children and adolescents with different BMI and WC in a large population in Shandong, China. Methods A total of 38,822 students (19,456 boys and 19,366 girls) aged 7–17 years participated in this study. Height, weight, WC, and BP of all subjects were measured, and BMI was calculated. The prevalence of overweight and obesity was obtained according to the International Obesity Task Force (IOTF) cutoffs; central obesity was defined as WC C 90th percentile (P90); relatively high BP status was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) C 95th percentile for age and gender. Results Within each BMI categories (normal weight, overweight, and obesity), children and adolescents with WC C P90 had higher BP levels than those with WC \ P90 (p \ 0.01). When BMI and WC were combined, the highest and lowest prevalences of relatively high BP were noted in obese with WC C P90 group (54.52 % for boys
Y.-X. Zhang (&) Shandong Center for Disease Control and Prevention, 16992 Jingshi Road, Jinan 250014, Shandong, China e-mail:
[email protected] S.-R. Wang Shandong Blood Center, 22 Shanshidong Road, Jinan 250014, Shandong, China e-mail:
[email protected]
and 48.71 % for girls) and normal weight with WC \ P90 group (17.00 % for boys and 14.13 % for girls). Conclusion Children and adolescents with high BMI and high WC might have an increased risk of elevated BP. Our results suggest that the additional measurement of WC is better than BMI alone to help identify high BP risks. Keywords Body mass index Waist circumference Blood pressure Obesity Adolescent
Introduction Several studies have provided ample evidence that hypertension in adults has its onset in childhood resulting in increasing concern with monitoring arterial blood pressure (BP) in children [1, 2]. More and more evidence showed that children with elevated BP are more likely to become hypertensive adults [3–7]. Unfortunately, the prevalence of high BP has been increasing in children and adolescents [8–11]. The increase in childhood high BP not only increases the prevalence of hypertension in later adulthood decades, but also further correlates with increased cardiovascular morbidity and mortality [9, 12]. Based on these observations, early detection and intervention in children with elevated BP is an important action for the control and prevention of hypertension in adulthood. It is well known that many chronic diseases, such as diabetes, hypertension, and cardiovascular disease (CVD), are related to increased body fat, which can be evaluated by anthropometric indicators. Body mass index (BMI) is perhaps the most commonly used measure for defining overweight and obesity in clinical and public health settings [13]. Several studies have demonstrated that BMI is strongly associated with elevated BP in children and
123
Eur J Nutr
adolescents [14–16]. However, BMI is an indicator of general obesity, reflecting neither abdominal fat nor body fat distribution. Recent evidence suggests that the distribution of adipose tissue influences CVD risk and specifically that abdominal (or visceral) adiposity is more closely related to CVD risk than peripheral, subcutaneous adiposity [17]. For the measurement of central obesity, some anthropometric indicators, such as waist circumference (WC) and waist-to-height ratio (WHtR), are used in general practice. In this article, we compared the BP levels among children and adolescents with different BMI and WC in a large population in Shandong, China.
Subjects and methods The study was approved by the Ethical Committee of the Shandong Center for Disease Control and Prevention, Shandong, China. Study population Data for this study were obtained from a large cross-sectional survey of schoolchildren. A total of 38,822 students (19,456 boys and 19,366 girls) from 16 districts in Shandong Province, students of Han nationality, aged 7–17 years, participated in the National Surveys on Chinese Students’ Constitution and Health, which were carried out in September to October 2010. (The first author is the leader of the investigation team in Shandong.) All subjects voluntarily joined this study with informed consents. The sampling method was stratified multistage sampling based on selected primary and secondary schools. Six public schools (two primary schools, two junior high schools, and two senior high schools) from each of the 16 districts in Shandong were randomly selected and invited to participate in the study. From the selected schools, two classes in each grade were selected, and all students of the selected classes were invited to join the study. All subjects were primary and secondary students, ranging from 7 to 17 years of age, and all were of Han ancestry that accounts for *99.32 % of the total population in Shandong. Age groups were divided according to criteria of ‘exact age’, so that, for example, cohort 7.5 (represented by ‘7.5’ in the plots) designates students aged 7.0–7.9 years.
apparatus and followed the same procedures. Height without shoes was measured using metal column height-measuring stands to the nearest 0.1 cm. Weight was measured using lever scales to the nearest 0.1 kg, while the subjects wore their underwear only. WC was measured midway between the lowest rib and the superior border of the iliac crest with an inelastic measuring tape at the end of normal expiration to the nearest 0.1 cm [18]. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using a mercury sphygmomanometer after each subject had rested for at least 15 min in a sitting position. BP was measured twice on the right arm with an appropriately sized cuff, and the average value was recorded on the study form [19]. DBP was defined via Korotkoff sound 5. Body mass index (BMI) was calculated from their height and weight (kg/m2). Definitions The prevalence rates of overweight and obesity were obtained according to the International Obesity Task Force (IOTF) cutoffs using BMI [20]. Children and adolescents with a BMI below the cutoff point for overweight were defined as normal weight. Central obesity was defined by previously published WC references (C90th percentile, P90) based on Chinese national data [18]. Based on the national data, BP reference standards for Chinese children and adolescents have been established in 2010 [21], and the reference values of SBP and DBP percentiles for Chinese children and adolescents were applied in this study. Relatively high BP status was defined as SBP and/or DBP C 95th percentile for age and gender. Statistical analyses Z-scores of SBP and DBP were calculated from the national reference values [19]. All subjects were classified according to BMI (normal weight, overweight, and obesity) and WC (WC \ P90 and WC C P90), respectively. Comparisons of SBP and DBP among different groups were made by one-way ANOVA and t test. Comparisons of relatively high BP frequencies between different groups were made by Chi-square test. All analyses were performed with the statistical package SPSS/PC ? version 11.5. Significance was defined at the 0.05 level.
Measurements
Results
All measurements were conducted by a team of trained technicians in each of the 16 districts. Each technician is required to pass a training course for anthropometric measurement organized by the investigation team in Shandong. All measurements were taken using the same type of
Distributions of BMI, WC, and BP
123
The anthropometric and BP characteristics for children and adolescents aged 7–17 years in the sample are shown in Table 1. The mean values of BMI, WC, SBP, and DBP
Eur J Nutr
increased with age in both boys and girls, and in all observed age periods, the boys were seen to dominate (p \ 0.05 or 0.01). For boys, the mean values of BMI, WC, SBP, and DBP increased from 17.03 kg/m2, 57.83 cm, 101.53, and 64.57 mmHg at 7 years to 21.70 kg/m2, 74.63 cm, 119.73, and 73.62 mmHg by 17 years and for girls, from 16.26 kg/m2, 54.78 cm, 99.99, and 63.52 mmHg at 7 years to 20.93 kg/m2, 69.56 cm, 109.74, and 70.41 mmHg by 17 years. Prevalences of overweight, obesity, and relatively high BP The overall prevalences of overweight, obesity, and relatively high BP were 16.56, 6.73, and 24.08 % for boys and 11.08, 2.22, and 18.09 % for girls; 20.39 and 16.87 % of boys and girls had a WC C P90, v2 tests indicated that all the figures of boys were significantly higher than girls (p \ 0.01). Comparison of BP levels in different groups The characteristics of BP among different groups based on BMI and WC separately are presented in Table 2. The Z-scores of BP and the prevalence of relatively high BP for both boys and girls were all significantly higher in the WC C P90 groups than in the WC \ P90 groups Table 1 Anthropometric and blood pressure measurements
Age/years
n
(p \ 0.01). For both boys and girls, when BMI was used to diagnose normal weight, overweight, and obese adolescents separately, an increasing trend was observed in SBP, DBP, and the prevalence of relatively high BP from the normal weight group to the overweight and obese groups (p \ 0.01). For example, the prevalence of relatively high BP in the three groups was 17.93, 40.69, and 53.32 % for boys and 15.35, 33.66, and 47.55 % for girls, respectively, and a graded increase trend is very obvious. The characteristics of BP in subgroups based on BMI ? WC are presented in Table 3. Within each BMI categories (normal weight, overweight, and obesity), children and adolescents with WC C P90 had higher BP levels than those with WC \ P90 (p \ 0.01). When BMI and WC were combined, the highest and lowest prevalences of relatively high BP were noted in obese with WC C P90 group (54.52 % for boys and 48.71 % for girls) and normal weight with WC \ P90 group (17.00 % for boys and 14.13 % for girls); normal weight with WC C P90 group had similar prevalence to overweight with WC \ P90 group (35.32 vs 33.93 % for boys, 29.40 vs 27.12 % for girls). Figures 1 and 2 show the mean values of SBP and DBP in normal weight with WC \ P90 and obese with WC C P90 children and adolescents. Boys and girls in obese with WC C P90 group had higher SBP and DBP
BMI (kg/m2)
WC (cm)
SBP (mm Hg)
DBP (mm Hg)
Boys 7.5
1755
17.03 ± 3.04
57.83 ± 8.69
101.53 ± 12.38
64.57 ± 10.78
8.5
1872
17.47 ± 3.21
60.48 ± 8.82
102.40 ± 12.51
64.67 ± 10.91
9.5 10.5
1742 1809
18.08 ± 3.43 18.81 ± 3.54
62.41 ± 9.68 64.72 ± 10.48
103.67 ± 12.00 105.19 ± 12.23
65.97 ± 11.14 66.84 ± 10.52
11.5
1796
19.21 ± 3.75
66.78 ± 10.98
107.69 ± 12.54
68.36 ± 10.42
12.5
1782
19.70 ± 3.87
68.97 ± 10.93
108.82 ± 12.33
68.77 ± 8.99
13.5
1762
20.14 ± 3.90
69.75 ± 10.78
112.65 ± 11.78
69.42 ± 8.71
14.5
1672
20.26 ± 3.67
71.83 ± 10.14
114.52 ± 11.97
70.20 ± 8.45
15.5
1811
20.94 ± 3.74
73.35 ± 10.22
117.80 ± 11.75
72.08 ± 8.24
16.5
1718
21.25 ± 3.62
73.80 ± 9.37
119.42 ± 11.68
73.24 ± 8.26
17.5
1737
21.70 ± 3.41
74.63 ± 9.17
119.73 ± 11.62
73.62 ± 8.55
1790
16.26 ± 2.51**
54.78 ± 6.90**
Girls 7.5
Data presented as mean ± SD. Gender difference: * p \ 0.05, ** p \ 0.01
99.99 ± 12.43**
63.52 ± 11.46**
8.5
1797
16.38 ± 2.53**
57.23 ± 6.91**
100.12 ± 11.93**
63.64 ± 11.00**
9.5
1822
16.97 ± 2.82**
58.86 ± 7.81**
101.43 ± 12.14**
64.78 ± 10.02**
10.5
1824
17.74 ± 3.02**
61.44 ± 8.49**
104.33 ± 12.24*
66.02 ± 10.38*
11.5
1757
18.12 ± 3.09**
62.76 ± 8.43**
106.11 ± 12.36**
67.58 ± 9.90*
12.5
1721
18.59 ± 3.07**
65.00 ± 8.06**
106.41 ± 11.50**
68.03 ± 8.78*
13.5 14.5
1761 1706
19.28 ± 2.98** 19.93 ± 3.12**
66.67 ± 8.26** 67.61 ± 7.74**
108.71 ± 10.11** 109.26 ± 11.06**
68.55 ± 8.13** 69.31 ± 8.28**
15.5
1782
20.38 ± 3.04**
68.49 ± 7.29**
109.57 ± 10.71**
69.54 ± 7.78**
16.5
1681
20.78 ± 2.85**
69.42 ± 7.14**
109.68 ± 11.28**
69.67 ± 8.34**
17.5
1725
20.93 ± 2.72**
69.56 ± 8.08**
109.74 ± 10.78**
70.41 ± 8.33**
123
123 F = 402.83, P = 0.000
F = 736.68, P = 0.000
0.78 ± 1.01 1.12 ± 1.03
1.44 ± 1.13
0.99 ± 1.12
0.44 ± 0.97
t = 26.84, P = 0.000
t = 34.97, P = 0.000
0.46 ± 1.06
0.44 ± 0.98 0.91 ± 1.00
ZDBP
0.48 ± 1.06 1.15 ± 1.14
ZSBP
x2 = 1407.32, P = 0.000
53.32 (50.62–56.02)
40.69 (38.99–42.39)
17.93 (17.31–18.55)
x2 = 1316.25, P = 0.000
18.45 (17.84–19.06) 46.05 (44.50–47.60)
RHBP (95 %CI)
429
2145
16792
16098 3268
n
Girls
F = 344.73, P = 0.000
1.44 ± 1.29
0.96 ± 1.13
0.46 ± 1.09
t = 23.61, P = 0.000
0.45 ± 1.09 0.95 ± 1.17
ZSBP
F = 237.17, P = 0.000
1.24 ± 1.09
0.80 ± 1.01
0.45 ± 0.99
t = 21.51, P = 0.000
0.44 ± 0.99 0.85 ± 1.01
ZDBP
x2 = 687.05, P = 0.000
47.55 (42.82–52.28)
33.66 (31.66–35.66)
15.35 (14.80–15.90)
x2 = 750.58, P = 0.000
14.68 (14.13–15.23) 34.91 (33.28–36.54)
RHBP (95 %CI)
756
15445
1347
WC \ P90
WC C P90
0.43 ± 0.99 0.73 ± 0.98a
0.65 ± 1.12a
0.72 ± 0.93a
0.44 ± 1.08
0.42 ± 0.97
0.65 ± 1.11a
ZDBP
0.45 ± 1.06
ZSBP
29.40b
14.13
35.32b
17
RHBP (%)
1533
612
1984
1238
n
1.07 ± 1.11a
0.70 ± 1.13
1.14 ± 1.11a
0.75 ± 1.08
ZSBP
Overweight
0.85 ± 1.00a
0.69 ± 1.03
0.85 ± 1.00a
0.67 ± 1.01
ZDBP
b
a
Statistically significant compared with WC \ P90 group by t test (p \ 0.01) Statistically significant compared with WC \ P90 group by x2 test (p \ 0.01)
Data of ZSBP and ZDBP presented as mean ± SD, relatively high BP presented as percentage. RHBP, relatively high BP
Girls
14169
WC \ P90
WC C P90
Boys
n
Normal weight
Subgroup
Gender
36.27b
27.12
44.91b
33.93
RHBP (%)
82
388
41
1227
n
Obesity
1.50 ± 1.29a
0.89 ± 1.04
1.48 ± 1.09a
0.90 ± 1.24
ZSBP
1.29 ± 1.07a
0.83 ± 1.02
1.14 ± 1.03a
0.83 ± 1.07
ZDBP
48.71
36.59
54.52b
35.37
RHBP (%)
Table 3 Comparisons of Z-score of SBP and DBP and the prevalence of relatively high BP in subgroups based on BMI ? WC among children and adolescents aged 7–17 years
Data of ZSBP and ZDBP presented as mean ± SD, relatively high BP presented as percentage. RHBP, relatively high BP
3222
14925
1309
Normal weight
BMI
15489 3967
Overweight
WC \ P90 WC C P90
WC
n
Boys
Obesity
Group
Target
Table 2 Comparisons of Z-score of SBP and DBP and the prevalence of relatively high BP in different groups based on BMI and WC among children and adolescents aged 7–17 years
Eur J Nutr
Eur J Nutr 140 130 120
mm Hg
110 100 90 80 70 60 50 40
SBP2
SBP1 7
8
9
10
11
12
DBP1 13
14
DBP2 15
16
17
Age/years
Fig. 1 Comparison of the mean values of SBP and DBP for boys with different BMI and WC levels. 1. Normal weight with WC \ P90; 2. Obesity with WC C P90
levels than their counterparts in normal weight with WC \ P90 group in all age groups (7–17 years), the range of differences being 7.9–14.7, 5.6–7.3 mmHg for boys and 9.2–15.7, 5.6–9.8 mmHg for girls. Figure 3 shows the prevalence of relatively high BP in children and adolescents categorized by BMI ? WC. All subjects were divided into four groups (normal BMI with normal WC, high BMI with normal WC, normal BMI with high WC, and high BMI with high WC), high BMI (overweight or obesity) with high WC (CP90) group had the highest prevalence of relatively high BP (48.58 % for boys and 38.78 % for girls), followed by normal BMI with high WC and high BMI with normal WC groups, and no statistical significant differences were observed between the normal BMI with high WC group and the high BMI with normal WC group (p [ 0.05).
Discussion 140 130 120
mm Hg
110 100 90 80 70 60 50 40
SBP2
SBP1
7
8
9
10
11
12
DBP1
13
14
DBP2
15
16
17
Age/years
Fig. 2 Comparison of the mean values of SBP and DBP for girls with different BMI and WC levels. 1. Normal weight with WC \ P90; 2. Obesity with WC C P90
60 50
%
40
Girls 34.02 27.71
30 20
48.58
Boys
17.00
35.32
38.78
29.40
14.13
10 0
Nomal BMI with normal WC
High BMI with Normal BMI with normal WC high WC
High BMI with high WC
Fig. 3 Prevalence of relatively high BP in children and adolescents categorized by BMI and WC (High BMI: overweight or obesity; High WC: WC C P90)
Several anthropometric indicators (such as BMI, WC, and WHtR) have been used to investigate the association between adiposity and high BP in both adults and children. However, It has been recognized that BMI is often used to reflect total body fat amounts (general obesity), while WC and WHtR are used as surrogates for body fat centralization (central obesity). Compared with general obesity, central obesity appears to be more strongly associated with CVD risk factors [17, 22, 23]. To the best of our knowledge, this is the first study examining the relationship between BP level and two commonest anthropometric measurements for obesity (BMI and WC) among children and adolescents in Shandong, china, and the results of this article will provide valuable evidence for the control of obesity and high BP. A number of studies have demonstrated that there is a strong positive relationship between BMI and BP level in children and adolescents [14–16, 24], conclusively demonstrating that BP is significantly elevated in children within the upper percentiles of BMI relative to their leaner peers. Recent studies in both children and adults indicate that WC, a measure of central obesity, is more closely related to CVD risk factors than BMI [22, 23]. The 90th percentile of WC is commonly suggested as a cutoff point at and above which the risk for CVD increases substantially [25–27]. In a sample of Italian children aged 3–11, those with WC greater than the 90th percentile were more likely (19 %) to have multiple CVD risk factors, compared with children with values below the 90th percentile (9.4 %) [28]. The WHtR has also been proposed as a measure of central obesity, and studies in adults and children have suggested a cut point of 0.5 as a simple means of indicating whether the amount of central fat is excessive [29, 30]. In
123
Eur J Nutr
our study, we found that the BP level and the prevalence of relatively high BP were all significantly higher in the WC C P90 group than in the WC \ P90 group, even within the same BMI category. These findings strongly suggest that central obesity is a key determinant of elevated BP and a major contributing factor to the rising prevalence of high BP in children and adolescents. It has been recognized that individuals with a similar BMI can vary considerably in their abdominal fat mass, particularly among Asian populations where individuals may exhibit a ‘normal’ BMI but have a disproportionately large WC [31]. In the current study, we found that 5.07 and 8.02 % of the normal weight boys and girls had central obesity (WC C P90), normal weight with WC C P90 group had significantly higher prevalence of relatively high BP than those with normal WC values; even similar to those overweight with WC \ P90 group, these findings indicated that normal weight children with central obesity should be considered to be high risk children and would be missed if screening by BMI alone. We also found that obese children with central obesity had the highest prevalence of relatively high BP, while normal weight children with normal WC had the lowest. Our results, together with those of previous studies [32–34], suggest that the additional measurement of WC is better than BMI alone to help identify high BP risks, measurement of WC within BMI categories as a screening tool for high BP among children and adolescents. The worldwide increase in the prevalence of childhood overweight and obesity is a cause for serious concern, since it is associated with potential short- and long-term impacts on public health [35, 36]. The ongoing rise in the prevalence of hypertension in children and adolescents is considered to be accompanied with the epidemic of childhood overweight and obesity. Freedman et al. [37] reported that overweight children in the Bogalusa Heart Study were 4.5 and 2.4 times as likely to have elevated SBP and DBP, respectively; Sorof and Daniels [38] reported a 3 times greater prevalence of hypertension in obese compared with nonobese adolescents in a school-based hypertension and obesity screening study; Croix and Feig [39] also reported that overweight and obese children face an approximately threefold higher risk for essential hypertension than do normal weight children. Interestingly, national survey data have indicated a trend toward an overall rise in average BP values in children in the United States, which the authors attributed to the increasing prevalence of overweight in youth [24]. Shandong Province is an important littoral province in East China (with a population of 95.79 million in 2010). The national data confirmed that Shandong Province is one of the areas of China with higher prevalence of overweight and obesity among children and adolescents [40]. Shandong Province is also one of the areas of China with higher prevalence of hypertension; data of the China Health and
123
Nutrition Survey conducted in 2002 show that the prevalence of hypertension among adults in Shandong had reached 29.22 % [41]. In the current study, we found that the prevalence rates of combined overweight and obesity had reached 23.29 % (boys) and 13.30 % (girls); corresponding prevalence rates of relatively high BP were 24.08 % (boys) and 18.09 % (girls). These figures confirmed that the prevalence of overweight/obesity and high BP among Shandong children and adolescents has become a serious public health problem, which would arouse special attention. Comprehensive strategies of intervention should include periodical monitoring, education on pattern of nutrition, healthy dietary behavior, and oxygen-consuming physical exercises. The major strength of this study is that, considered the dual effects of general and central obesity on blood pressure, compares the BP level among children and adolescents with different BMI and WC in a large population. However, this study has several limitations. First, the BP reading was recorded as the average of two measurements, which were taken after a 15-min rest, but on one occasion only (the definition of high BP should be based on BP measured on at least three separate occasions [42]); Thus, the possibility that errors may have occurred in classifying adolescents as having high BP or normal BP cannot be ruled out. However, the purpose of using BP categories in the analysis was to obtain a general idea of the extent of elevated BP in the studied adolescents rather than to diagnose the presence of hypertension among them. Thus, in this paper, we use the term ‘relative high BP’ rather than ‘high BP’. Second, the absence of detailed information concerning living environments, nutritional status, dietary pattern, and physical activity at the individual level also limited our study. Third, because of various restraints, other biochemical indicators (e.g., blood lipids and blood glucose) were not measured. We hope that future studies to be conducted will address this area. In summary, the present study further highlights that BMI and WC are associated with BP level in children and adolescents. Children and adolescents with high BMI and high WC might have an increased risk of elevated BP. Our results suggest that the additional measurement of WC is better than BMI alone to help identify high BP risks, measurement of WC within BMI categories as a screening tool for high BP among children and adolescents. These findings also emphasize the importance of the prevention of overweight and obesity in order to prevent future-related problems such as hypertension in children and adolescents. Acknowledgments This study was supported by the medical and health program of Shandong, China (2009-HZ049). Surveys on students’ constitution and health are conducted under the auspices of the department of education in Shandong Province, China. We thank all the team members and all participants. Special thanks to Mr. B Yu for providing access to the survey data.
Eur J Nutr Conflicts of interest any of the authors.
There are no conflicts of interest on behalf of
References 1. Rosner B, Prineas RJ, Loggie JMH, Daniels SR (1993) Blood pressure nomograms for children and adolescents, by height, sex and age, in the United States. J Pediatr 123:871–886 2. Lurbe E, Redon J (2000) Ambulatory blood pressure monitoring in children and adolescents: the future. J Hypertens 18:1351–1354 3. Bao W, Threefoot SA, Srinivasan SR, Berenson GS (1995) Essential hypertension predicted by tracking of elevated blood pressure from childhood to adulthood: the bogalusa heart study. Am J Hypertens 8:657–665 4. Cook NR, Gillman MW, Rosner BA, Taylor JO, Hennekens CH (1997) Prediction of young adult blood pressure from childhood blood pressure, height, and weight. J Clin Epidemiol 50:571–579 5. Vos LE, Oren A, Bots ML, Gorissen WH, Grobbee DE, Uiterwaal CS (2003) Does a routinely measured blood pressure in young adolescence accurately predict hypertension and total cardiovascular risk in young adulthood? J Hypertens 21:2027–2034 6. Sun SS, Grave GD, Siervogel RM, Pickoff AA, Arslanian SS, Daniels SR (2007) Systolic blood pressure in childhood predicts hypertension and metabolic syndrome later in life. Pediatrics 119:237–246 7. Chen X, Wang Y (2008) Tracking of blood pressure from childhood to adulthood: a systematic review and meta-regression analysis. Circulation 117:3171–3180 8. Nguyen M, Mitsnefes M (2007) Evaluation of hypertension by the general pediatrician. Curr Opin Pediatr 19:165–169 9. Feber J, Ahmed M (2010) Hypertension in children: new trends and challenges. Clin Sci 119:151–161 10. Liang YJ, Xi B, Hu YH, Wang C, Liu JT, Yan YK, Xu T, Wang RQ (2011) Trends in blood pressure and hypertension among Chinese children and adolescents: China Health and Nutrition Surveys 1991–2004. Blood Press 20:45–53 11. Zhang YX, Zhao JS, Sun GZ, Lin M, Chu ZH (2012) Prevalent trends in relatively high blood pressure among children and adolescents in Shandong, China. Ann Hum Biol 39:259–263 12. Daniels SR, Pratt CA, Hayman LL (2011) Reduction of risk for cardiovascular disease in children and adolescents. Circulation 124:1673–1686 13. Barton M (2010) Screening for obesity in children and adolescents: US Preventive Services Task Force recommendation statement. Pediatrics 125:361–367 14. Makgae PJ, Monyeki KD, Brits SJ, Kemper HCG, Mashita J (2007) Somatotype and blood pressure of rural South African children aged 6–13 years: Ellisras longitudinal growth and health study. Ann Hum Biol 34:240–251 15. Ataei N, Hosseini M, Iranmanesh M (2009) The relationship of body mass index and blood pressure in Iranian children, 7 years old. J Trop Pediatr 55:313–317 16. Zhang YX, Wang SR (2011) The relationship of body mass index distribution to relatively high blood pressure among children and adolescents in Shandong, China. Ann Hum Biol 38:630–634 17. Despres JP, Lemieux I (2006) Abdominal obesity and metabolic syndrome. Nature 444:881–887 18. Ji CY, Sung RYT, Ma GS, Ma J, He ZH, Chen TJ (2010) Waist circumference distribution of Chinese school-age children and adolescents. Biomed Environ Sci 23:12–20 19. Research Section of the Constitution and Health of Chinese Students (RSCHCS) (2007) Report on the physical fitness and health surveillance of Chinese school students. Higher Education Press, Beijing, pp 161–177 [in Chinese]
20. Cole TJ, Bellizzi MC, Flegal KM, Dietz WH (2000) Establishing a standard definition for child overweight and obesity worldwide: international study. BMJ 320:1240–1243 21. Mi J, Wang TY, Meng LH, Zhu GJ, Han SM, Zhong Y, Liu GM, Wan YP, Xiong F, Shi JP, Yan WL, Zhou PM (2010) Development of blood pressure reference standards for Chinese children and adolescents. Chin J Evid Based Pediatr 15:4–14 [in Chinese] 22. Savva SC, Tornaritis M, Savva ME, Kourides Y, Panagi A, Silikiotou N, Georgiou C, Kafatos A (2000) Waist circumference and waist-to-height ratio are better predictors of cardiovascular disease risk factors in children than body mass index. Int J Obes Relat Metab Disord 24:1453–1458 23. Janssen I, Katzmarzyk PT, Ross R (2004) Waist circumference and not body mass index explains obesity-related health risk. Am J Clin Nutr 79:379–384 24. Muntner P, He J, Cutler JA, Wildman RP, Whelton PK (2004) Trends in blood pressure among children and adolescents. JAMA 91:2107–2113 25. Weiss R, Dziura J, Burgert TS, Tamborlane WV, Taksali SE, Yeckel CW, Allen K, Lopes M, Savoye M, Morrison J, Sherwin RS, Caprio S (2004) Obesity and the metabolic syndrome in children and adolescents. New Engl J Med 350:2362–2374 26. Lee JM, Davis MM, Woolford SJ, Gurney JG (2009) Waist circumference percentile thresholds for identifying adolescents with insulin resistance in clinical practice. Pediatr Diabetes 10:336–342 27. Poh BK, Jannah AN, Chong LK, Ruzita AT, Ismail MN, Mccarthy D (2011) Waist circumference percentile curves for Malaysian children and adolescents aged 6.0–16.9 years. Int J Pediatr Obes 6:229–235 28. Maffeis C, Pietrobelli A, Grezzani A, Provera S, Tato L (2001) Waist circumference and cardiovascular risk factors in prepubertal children. Obes Res 9:179–187 29. McCarthy HD, Ashwell M (2006) A study of central fatness using waist-to-height ratios in UK children and adolescents over two decades supports the simple message: ‘keep your waist circumference to less than half your height’. Int J Obes (Lond) 30:988–992 30. Garnett SP, Baur LA, Cowell CT (2008) Waist-to-height ratio: a simple option for determining excess central adiposity in young people. Int J Obes (Lond) 32:1028–1030 31. Huxley R, Mendis S, Zheleznyakov E, Reddy S, Chan J (2010) Body mass index, waist circumference and waist:hip ratio as predictors of cardiovascular risk: a review of the literature. Eur J Clin Nutr 64:16–22 32. Lee S, Bacha F, Arslanian SA (2006) Waist circumference, blood pressure, and lipid components of the metabolic syndrome. J Pediatr 149:809–816 33. Kovacs VA, Gabor A, Fajcsak Z, Martos E (2010) Role of waist circumference in predicting the risk of high blood pressure in children. Int J Pediatr Obes 5:143–150 34. Khoury M, Manlhiot C, Dobbin S, Gibson D, Chahal N, Wong H, Davies J, Stearne K, Fisher A, McCrindle BW (2012) Role of waist measures in characterizing the lipid and blood pressure assessment of adolescents classified by body mass index. Arch Pediatr Adolesc Med 166:719–724 35. Ebbeling CB, Pawlak DB, Ludwig DS (2002) Childhood obesity: public health crisis, common sense cure. Lancet 360:473–482 36. Lobstein T, Baur L, Uauy R (2004) Obesity in children and young people: a crisis in public health. Obes Rev 5(Suppl 1):4–85 37. Freedman DS, Dietz WH, Srinivasan SR, Berenson GS (1999) The relation of overweight to cardiovascular risk factors among children and adolescents: the Bogalusa Heart Study. Pediatrics 103:1175–1182 38. Sorof J, Daniels S (2002) Obesity hypertension in children. A problem of epidemic proportions. Hypertension 40:441–447
123
Eur J Nutr 39. Croix B, Feig DI (2006) Childhood hypertension is not a silent disease. Pediatr Nephrol 21:527–532 40. Ji CY, Cheng TO (2008) Prevalence and geographic distribution of childhood obesity in China in 2005. Int J Cardiol 131:1–8 41. Zhou JY, Zhang JL (2008). Dietary nutrition and health status of Shandong population. Jinan, Shandong, China: Shandong electronic audio & video publishing house p. 17 [in Chinese]
123
42. National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents (2004) The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics 114:555–576
