Table 2

Differences in outcome and predictor variables, based on children’s age, sex, socioeconomic status and ethnicity of 650 children from Port Elizabeth, South Africa, in February and March 2018

AgeSex
10–12 years13–15 yearsBoysGirls
MSDMSDFη2MSDMSDFη2
Systolic blood pressure (mm Hg)108.511.0111.111.68.7**0.001109.112.1109.910.60.8
Diastolic blood pressure (mm Hg)65.97.867.58.46.4**0.01065.88.267.28.04.5*0.007
Skinfolds (mm)11.46.210.66.12.88.95.213.06.381.1***0.111
Total cholesterol (mmol/L)3.60.73.50.62.43.50.63.60.73.8
HDL cholesterol (mmol/L)1.40.31.40.32.21.40.41.40.30.0
LDL cholesterol (mmol/L)1.80.51.80.60.91.70.51.80.63.0
Triglycerides (mmol/L)0.80.30.80.30.00.80.30.80.37.2**0.011
HbA1c (%)5.50.25.50.32.55.50.25.50.28.3**0.013
Clustered risk index0.02.80.03.10.2−0.52.90.42.816.4***0.025
Sedentary activity670.577.8652.393.47.2**0.011643.488.5680.477.332.4***0.048
Light physical activity (min/day)266.846.3254.255.49.9**0.015269.847.8255.151.614.0***0.021
Moderate physical activity (min/day)48.519.254.219.413.6***0.02160.518.742.516.0174.9***0.213
Vigorous physical activity (min/day)20.814.923.316.53.9*0.00630.517.514.48.3235.1***0.266
Moderate-to-vigorous physical activity (min/day)69.332.377.533.49.7**0.01591.033.556.822.8236.2***0.266
Cardiorespiratory fitness (laps in 20 m shuttle run test)33.318.741.121.723.2***0.03648.020.226.414.0250.7***0.284
Socioeconomic status† Ethnicity‡
Lower (0–7)Higher (8–9)Black AfricanColoured
MSDMSDFη2 MSDMSDFη2
Systolic blood pressure (mm Hg)109.711.3109.311.40.2108.811.6110.310.82.7
Diastolic blood pressure (mm Hg)66.48.066.68.20.165.48.468.47.420.7***0.033
Skinfolds (mm)10.05.311.76.69.1**0.01511.96.510.05.713.70.022
Total cholesterol (mmol/L)3.60.63.50.71.53.50.63.70.712.7***0.020
HDL cholesterol (mmol/L)1.40.31.40.31.11.40.31.40.32.6
LDL cholesterol (mmol/L)1.80.51.80.62.71.70.51.80.64.8*0.008
Triglycerides (mmol/L)0.80.30.80.32.20.80.30.90.315.6**0.025
HbA1c (%)5.50.25.50.20.35.50.25.50.23.0
Clustered risk index0.02.8−0.23.00.1−0.13.00.12.90.6
Sedentary activity662.384.4665.583.40.2676.678.2643.788.323.2***0.036
Light physical activity (min/day)259.849.0261.851.30.2268.546.1250.055.719.8***0.031
Moderate physical activity (min/day)51.419.549.719.21.147.818.154.920.819.9***0.031
Vigorous physical activity (min/day)21.315.021.615.90.120.114.623.917.08.5**0.014
Moderate-to-vigorous physical activity (min/day)72.732.271.333.00.267.930.778.735.316.2***0.026
Cardiorespiratory fitness (laps in 20 m shuttle run test)40.020.735.020.17.8**0.01333.519.541.720.823.0***0.037
  • †N=37 participants had missing values for SES.

  • ‡ N=34 participants had missing values for ethnicity.

  • *p<0.05, **p<0.01, ***p<0.001.

  • Age: 10–12 years (n=395), 13–15 years (n=255); sex: boys (n=299), girls (n=351); socioeconomic status: lower (n=194), higher (n=419); ethnicity: black African (n=384), coloured (n=232).

  • HbA1c, blood glucose; HDL, high-density lipoprotein; LDL, low-density lipoprotein.