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Table 1 Characteristics of the included subjects

From: School-based surveillance on visit-to-visit blood pressure variability and high blood pressure in children and adolescents

Variables, n (%) or mean (SD) Total population (N = 330,618) Normotensive (n = 252,342) HNBP (n = 35,722) HBP (n = 42,554) P value
Age, n (%)a      < 0.0001
 Child (9–9.9 years) 55,666 (16.84%) 39,255 (15.56%) 4841 (13.55%) 5964 (14.02%)  
 Adolescent (10–18 years) 274,952 (83.16%) 213,087 (84.44%) 30,881 (86.45%) 36,590 (85.98%)  
Body mass index (kg/m2)a 19.43 ± 3.67 19.09 ± 3.45 20.17 ± 3.90 20.83 ± 4.29  
Body mass indexa,b 0.40 ± 1.26 0.30 ± 1.23 0.64 ± 1.26 0.83 ± 1.28 < 0.0001
Sex, n (%)      < 0.0001
 Boys 177,905 (53.81%) 135,069 (53.53%) 19,408 (54.33%) 23,428 (55.05%)  
 Girls 152,713 (46.19%) 117,273 (46.47%) 16,314 (45.67%) 19,171 (44.95%)  
Region, n (%)      < 0.0001
 Rural 166,547 (50.37%) 127,465 (50.51%) 18,169 (50.86%) 20,913 (49.14%)  
 Urban 164,071 (49.63%) 124,877 (49.49%) 17,553 (49.14%) 21,641 (50.86%)  
Socioeconomic status, n (%)      < 0.0001
 HSES 155,239 (46.95%) 115,793 (45.89%) 18,292 (51.21%) 21,154 (49.71%)  
 LSES 175,379 (53.05%) 136,549 (54.11%) 17,430 (48.79%) 21,400 (50.29%)  
Median BP measurement times 5.19 ± 0.97 5.19 ± 0.97 5.21 ± 0.97 5.20 ± 0.97 0.341
BP at first attendance of HPPCA      
 SBP (mmHg) 98.19 ± 10.12 97.73 ± 9.90 99.19 ± 10.88 100.06 ± 10.51 < 0.0001
 DBP (mmHg) 62.48 ± 7.46 62.19 ± 7.36 63.17 ± 7.82 63.63 ± 7.58 < 0.0001
 SBPb − 0.08 ± 0.93 − 0.10 ± 0.92 0.04 ± 0.93 0.09 ± 0.96 < 0.0001
 DBPb 0.34 ± 0.66 0.32 ± 0.66 0.41 ± 0.66 0.43 ± 0.67 < 0.0001
BP in 2018      
 SBP (mmHg) 109.24 ± 13.18 105.09 ± 10.86 117.95 ± 8.98 126.71 ± 10.57 < 0.0001
 DBP (mmHg) 68.20 ± 8.21 65.73 ± 6.51 74.70 ± 6.62 77.46 ± 8.79 < 0.0001
 SBPb 0.18 ± 1.14 − 0.21 ± 0.91 0.98 ± 0.70 1.80 ± 0.83 < 0.0001
 DBPb 0.45 ± 0.71 0.23 ± 0.55 1.02 ± 0.57 1.27 ± 0.79 < 0.0001
Mean BP during 2012–2017      
 SBP (mmHg) 103.00 ± 7.82 102.09 ± 7.54 105.16 ± 7.69 106.62 ± 8.15 < 0.0001
 DBP (mmHg) 65.14 ± 5.26 64.59 ± 5.13 66.54 ± 5.20 67.23 ± 5.36 < 0.0001
 SBPb 0.11 ± 0.62 − 0.03 ± 0.57 0.41 ± 0.54 0.68 ± 0.57 < 0.0001
 DBPb 0.41 ± 0.41 0.33 ± 0.39 0.62 ± 0.39 0.72 ± 0.42 < 0.0001
VVV during 2012–2017      
 SBP-SDc 0.86 ± 0.39 0.82 ± 0.37 0.89 ± 0.41 1.06 ± 0.43 < 0.0001
 SBP-ARVc 1.01 ± 0.50 0.96 ± 0.47 1.05 ± 0.50 1.30 ± 0.57 < 0.0001
 SBP-CVc 14.27 ± 53,983.00 − 5.99 ± 61,536.74 31.62 ± 12,102.74 119.87 ± 7950.35 0.260
 DBP-SDc 0.59 ± 0.27 0.57 ± 0.26 0.63 ± 0.27 0.70 ± 0.29 < 0.0001
 DBP-ARVc 0.70 ± 0.35 0.67 ± 0.34 0.76 ± 0.35 0.85 ± 0.40 < 0.0001
 DBP-CVc 129.22 ± 26,661.00 57.83 ± 17,534.74 141.27 ± 3633.13 542.44 ± 60,727.95 0.108
  1. HBP, high blood pressure; HNBP, high normal blood pressure; SBP, systolic blood pressure; DBP, diastolic blood pressure; SD, standard deviation; ARV, actual real variability; CV, coefficient of variation; LSES, low socioeconomic status; HSES, high socioeconomic status
  2. aAge and Body mass index were measured when participants took examinations in 2018
  3. bAbsolute BP levels and BMI values were converted into z-scores
  4. cBP variability parameters were calculated based on BP z-scores during 2012–2017