5.2.1 Characteristics of children
Clinical characteristics of the children are presented in Table 12. According to modified NCEP and modified IDF definitions, the prevalence of MetS was 20.2% and 14.5%, respectively. According to the pediatric NCEP and IDF definitions, the prevalence of MetS was 1.7%.
Table 12. Clinical characteristics of the children in Study II.
All children
(n=173) Boys
(n=83) Girls
(n=90) Age (years) 7.7 (0.4 | 2.2) 7.7 (0.4 | 2.2) 7.6 (0.4 | 1.5) Body height (cm) 129 (5.1 | 28.7) 130.3 (4.5 | 23.8) 127.9 (5.4 | 28.7) Body height SDS 0.7 (0.9 | 4.9) 0.8 (0.8 | 4) 0.6 (0.9 | 4.9) Body weight (kg) 26.9 (4.3 | 23.9) 27.5 (4.3 | 21.6) 26.3 (4.2 | 23.9) Body weight SDS 0.4 (0.9 | 4.8) 0.5 (1 | 4.5) 0.3 (0.9 | 4.7) Body mass index (kg/m2) 16.1 (1.9 | 10.1) 16.1 (1.9 | 10) 16.0 (1.9 | 9.2) Body mass index SDS 0 (1 | 5.3) 0.1 (1.1 | 5.3) 0 (0.9 | 4.6) Waist circumference (cm) 56.4 (5 | 33) 57.3 (4.8 | 27.9) 55.6 (5.1 | 33) HDL cholesterol (mmol/l) 1.6 (0.3 | 2) 1.7 (0.3 | 1.4) 1.6 (0.3 | 2) Triglycerides (mmol/l) 0.6 (0.3 | 1.4) 0.6 (0.3 | 1.4) 0.6 (0.2 | 1.3) Glucose (mmol/l) 4.9 (0.4 | 3.2) 4.9 (0.4 | 3.2) 4.8 (0.4 | 2.5) Insulin (mU/l) 4.7 (2.4 | 12.7) 4.5 (2.2 | 12) 4.9 (2.5 | 12.5) Systolic blood pressure (mmHg) 100.2 (7. 0 | 40.7) 100.9 (6.9 | 40) 99.5 (7.0 | 34.7) Diastolic blood pressure (mmHg) 61.7 (7.3 | 42.7) 62.1 (8.2 | 42.7) 61.3 (6.4 | 34.7) Metabolic syndrome score 0.01 (3.4 | 20.4) 0.2 (3.3 | 15.2) -0.2 (3.5 | 20.4) Values are means, standard deviations, and differences between the highest and lowest values, expressed as: mean (SD | range). SDS, standard deviation score; HDL, high-density lipoprotein. All biochemical analyses were done from fasting plasma samples, except insulin from fasting serum samples.
A FST before the exercise test (°C) B FST after the exercise test (°C)
--- 95% limits of agreement (-8.7 and 4.6)
- - - - Mean of difference between visits (-2.0) --- 95% limits of agreement (-5.3 and 3.4) - - - - Mean of difference between visits (-1.0) Figure 8. Bland-Altman plots of finger skin temperature (FST) before and after the exercise test.
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5.2.2 SI, RI, and FST before and after the exercise test
As presented in Figure 9, the mean values of SI, RI, and FST before and after the exercise test were similar in boys and girls. RI decreased substantially and FST increased in response to exercise among boys and girls (p<0.001). The decrease in RI in response to exercise was greater among girls than boys (p=0.043). FST and RI at rest (r=-0.393, p<0.001) and their responses to acute exercise (r=-0.239, p=0.002) significantly correlated with each other, whereas FST and SI (r=-0.061, p=0.425) and RI and SI (r=0.148, p=0.053) at rest had no significant intercorrelations.
The within-subject coefficient of variation (CV) was 7.4% for SI, 12.2% for RI, and 1.0%
for FST before the exercise test and 5.3% for SI, 19.6% for RI, and 0.9% for FST after the exercise test.
5.2.3 Associations of arterial stiffness, arterial tone, and arterial reactivity with cardiometabolic risk factors
MetS score correlated positively with SI and FST and negatively with RI (Table 13). WC was positively correlated with FST, but negatively correlated with RI. Insulin and triglycerides were positively correlated with SI. HDL cholesterol was negatively correlated with FST. SBP was positively correlated with SI and FST, but negatively with RI. Furthermore, DBP was positively correlated with SI.
SI was also higher in those with MetS according to all definitions used (Figure 10 and 11).
Also FST was higher in those with MetS according to the modified NCEP and modified IDF definitions (Figure 10).
The MetS score and its components showed no statistically significant correlations with RI∆ and RI∆% among boys and girls combined (Table 13). However, gender modified the associations of WC with RI∆ (p=0.008 for interaction) and RI∆% (P=0.002 for interaction) and the associations of SBP with RI∆ (p=0.048 for interaction) and RI∆% (p<0.001 for interaction).
WC and SBP had negative correlations with RI∆ (r=-0.244, p=0.026 and r=-0.208, p=0.060) and RI∆% (r=-0.220, p=0.046 and r=-0.287, p=0.008) in boys and positive correlations with RI∆% in girls (r=0.266, p=0.011 and r=0.254, p=0.016), but WC and SBP were not correlated with RI∆
in girls. Gender also modified the association of MetS score with RI∆% (p=0.012 for interaction). MetS score correlated positively with RI∆% among girls (r=0.209, p=0.049) but had a borderline negative correlation with RI∆% in boys (r=-0.179, p=0.105).
HDL cholesterol correlated negatively with FST∆ and FST∆% among boys and girls combined (Table 13).
The MetS score remained a statistically significant determinant of SI after adjustment for age, gender, and heart rate (standardized regression coefficient β=0.230, p=0.001). Insulin (β=0.213, p=0.003) and triglycerides (β=0.171, p=0.016) also remained statistically significant determinants of SI after adjustment for age, gender, heart rate, and SBP measured just before exercise in supine position. The means of SI increased statistically significantly with increasing quartiles of the MetS score adjusted for age, gender, and heart rate (Figure 12).
The means of SI also increased statistically significantly with increasing quartiles of insulin adjustied for age, gender, heart rate, and SBP measured in the supine position just before exercise (Figure 12).
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Figure 9. Stiffness index, reflection index and finger skin temperature before and after the exercise test. In a paired samples t-test, statistically significant exercise-induced change in RI and FST was seen in both genders (** = p<0.001), but in an independent samples t test, the change in RI was statistically significantly smaller in boys (*= p=0.043).
Illustration as in Figure 4.
Figure 10. The means of the A stiffness index and B reflection index (RI), and finger skin temperature (FST) in groups of clustering of components (comp.) of metabolic syndrome (MetS) according to modified- definitions together with p value as assessed with independent samples t-test when compared to those having no features of MetS. NCEP , National Education Cholesterol Program; IDF, International Diabetes Federation.
tiffness index and eflection index (RI) and finger skin A B
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Table 13. Partial correlation coefficients of the metabolic syndrome (MetS) score and its components with stiffness index (SI), reflection index (RI), and finger skin temperature (FST) after adjustment for gender and age.
MetS
score Waist
circ. Insulin Glucose TRI HDL
chol SBP DBP
SI .258 .068 .238 .080 .199 -.042 .235 .190
(.001) (.379) (.002) (.299) (.009) (.583) (.002) (.013)
RI -.173 -.191 -.077 -.065 .053 .139 -.161 -.123
(.024) (.012) (.320) (.397) (.495) (.070) (.035) (.111)
FST .209 .228 -.034 .079 .033 -.223 .212 .099
(.006) (.003) (.662) (.308) (.672) (.004) (.005) (.199)
RI∆ -.067 -.050 -.086 -.051 .060 .029 -.062 -.063
(.383) (.513) (.267) (.508) (.439) (.712) (.422) (.412)
RI∆% -.002 .015 -.037 -.018 .046 -.013 -.017 -.027
(.980) (.842) (.632) (.814) (.556) (.866) (.828) (.726)
FST∆ .112 .096 -.066 .059 .028 -.205 .022 .077
(.147) (.210) (.390) (.448) (.717) (.007) (.775) (.320)
FST∆% .140 .114 -.065 .061 .038 -.241 .054 .095
(.068) (.138) (.400) (.430) (.623) (.002) (.486) (.220) Values are partial correlation coefficients and their P-values in parenthesis below. Values in bold indicate statistical significance at P<0.05. circ., circumference; ∆, exercise induced change (before-after); ∆%, percentual exercise induced change from baseline value: HDL chol, high-density lipoprotein cholesterol;
TRI, triglycerides; SBP/DBP, systolic/diastolic blood pressure.
Figure 11. The means of the A stiffness index and B reflection index (RI), and finger skin temperature (FST) in groups of clustering of components (comp.) of metabolic syndrome (MetS) according to pediatric - definitions together with p value as assessed with independent samples t-test when compared to those having no features of MetS.
NCEP, National Education Cholesterol Program; IDF, International Diabetes Federation.
A B
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5.3 ASSOCIATIONS OF CARDIORESPIRATORY FITNESS, PHYSICAL