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Table 1 Descriptive characteristics of participants stratified by sex and group

From: Sleep and BMI in South African urban and rural, high and low-income preschool children

  All (n = 198) Boys (n = 98) Girls (n = 100) P-value Rural Low (n = 111) Urban Low (n = 65) Urban High (n = 22) P-value
Age (y) 5.19 ± 0.69 5.29 ± 0.70 5.09 ± 0.67 0.037 5.05 ± 0.64a 5.36 ± 0.71a 5.38 ± 0.74 0.006
BMI (kg/m2) 15.4 (14.3, 16.2) 15.5 (14.9, 16.2) 14.9 (14.1, 16.1) 0.009 15.1 (14.1, 16.0) 15.8 (14.9, 16.7)b 14.8 (14.3, 15.5) 0.001
BMI-z score 0.05 (−0.72, 0.68) 0.16 (− 0.34, 0.73) − 0.23 (− 0.85, 0.53) 0.017 −0.08 (− 0.83, 0.53) 0.39 (− 0.27, 0.99)b −0.38 (− 0.88, 0.11) 0.001
HAZ −0.31 ± 1.01 −0.34 ± 0.98 −0.27 ± 1.04 0.658 −0.36 ± 0.97 −0.42 ± 1.03b 0.32 ± 0.99 0.007
WAZ − 0.17 ± 1.02 −0.09 ± 0.90 −0.25 ± 1.13 0.271 −0.30 ± 0.96 −0.02 ± 1.15 −0.02 ± 0.87 0.167
Thinness (%) 20.7 14.0 27.0 0.062 26.1 10.8b 22.7  
Normal (%) 71.2 77.0 64.0 68.5 73.8 77.3 0.017
Overweight/obese (%) 8.1 7.0 9.0 5.4 15.4b 0  
SB (min/d) 308.8 (279.3, 340.3) 308.2 (272.8, 337.3) 310.0 (281.6, 341.7) 0.509 292.1 (263.8, 330.6)b 321.1 (298.2, 345.7) 321.3 (304.5, 347.8) < 0.001
LPA (min/d) 337.8 ± 37.2 334.3 ± 37.3 341.3 ± 39.7 0.072 343.6 ± 35.6 339.1 ± 37.1 304.9 ± 29.0b < 0.001
MVPA (min/d) 123.6 (102.4, 146.9) 138.2 (110.3, 155.4) 112.6 (91.9, 134.4) < 0.001 121.8 (97.5, 146.9) 132.6 (112.8, 154.0) 112.0 (94.3, 132.0) 0.125
LMVPA (min/d) 464.1 ± 56.3 471.5 ± 56.9 456.8 ± 55.1 0.065 469.9 ± 54.8 469.8 ± 55.2 417.5 ± 46.9b < 0.001
  1. Data are presented as mean ± SD, median with interquartile range or percentage
  2. Significance was determined using independent t-tests, Mann Whitney-U, one-way ANOVA, Kruskal-Wallis ANOVA or Chi2 analyses
  3. Significance was accepted at p < 0.05
  4. BMI Body mass index, HAZ Height-for-age z-score, WAZ Weight-for-age z-score, SB Sedentary behaviour, LPA Light-intensity physical activity, MVPA Moderate- to vigorous-intensity physical activity, LMVPA Light- to vigorous-intensity physical activity
  5. aPost hoc analyses indicate significant differences between two marked groups
  6. bPost hoc analyses indicate that marked group is significantly different to the other two groups