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Table 1 Characteristics of the study population

From: How are academic achievement and inhibitory control associated with physical fitness, soil-transmitted helminth infections, food insecurity and stunting among South African primary schoolchildren?

   Total Males Females    
Age and anthropometry N M (SD) M (SD) M (SD) F p-value η2
 Age (years) 1277 8.3 (1.4) 8.4 (1.5) 8.2 (1.4) 6.2 0.013 0.005
 Height (cm) 1240 124.7 (9.2) 125.1 (9.0) 124.3 (9.4) 2.9 0.087 0.002
 Weight (kg) 1240 25.4 (6.9) 25.4 (6.6) 25.4 (7.2) 0.0 0.884 0.000
 BMI (kg/m2) 1240 16.1 (2.6) 16.0 (2.4) 16.1 (2.8) 0.5 0.470 0.000
Sociocultural characteristics N M (SD) M (SD) M (SD) F p-value η2
 Socioeconomic status (SES) 740 3.0 (1.2) 3.0 (1.2) 3.0 (1.2) 0.4 0.539 0.001
 Food insecurity* 940 1.3 (0.6) 1.3 (0.6) 1.2 (0.6) 2.6 0.111 0.003
Helminth infections and stunting N n (%) n (%) n (%) χ2 p-value  
 Infected 1245 89 (7.1) 50 (7.8) 39 (6.5) 0.8 0.383  
 Stunted 1231 112 (9.1) 48 (7.6) 64 (10.7) 3.6 0.057  
Physical fitness N M (SD) M (SD) M (SD) F p-value η2
 Grip strength (in kg) 1277 10.3 (12.0) 11.8 (12.9) 9.7 (10.9) 2.5 0.114 0.002
 Cardiorespiratory fitness (VO2max; in ml kg−1 min−1) 1277 43.9 (22.9) 44.1 (22.9) 43.7 (22.9) 0.1 0.761 0.000
Academic achievement N M (SD) M (SD) M (SD) F p-value η2
 End of year results 1045 4.6 (1.3) 4.4 (1.2) 4.8 (1.3) 35.9 0.000 0.033
 Language 1045 4.5 (1.3) 4.3 (1.2) 4.8 (1.3) 36.3 0.000 0.034
 Mathematics 1045 4.7 (1.3) 4.4 (1.2) 4.9 (1.4) 30.4 0.000 0.028
 Life skills 1045 5.0 (1.0) 4.8 (1.0) 5.2 (1.0) 39.7 0.000 0.037
Flanker task N M (SD) M (SD) M (SD) F p-value η2
 Accuracy (congruent stimuli) 1223 92.8 (10.8) 92.6 (11.1) 92.9 (10.5) 0.2 0.651 0.000
 Accuracy (incongruent stimuli) 1223 84.9 (19.4) 85.4 (18.2) 84.4 (20.6) 0.7 0.397 0.001
 Reaction time (congruent stimuli) 1223 1187.9 (240.4) 1155.7 (243.5) 1222.2 (232.3) 23.9 0.000 0.019
 Reaction time (incongruent stimuli) 1223 1273.6 (266.6) 1238.6 (262.5) 1310.9 (266.0) 22.7 0.000 0.018
  1. Notes. *26 children (2.8%) had a score of 0 (fully food secure), 685 children (72.9%) had a score of 1, 172 children (18.3%) had a score of 2 and 57 children (6.1%) had a score of 3 (severe food insecurity)