Table 2.
Characteristics of schoolchildren by hookworm infection
| Parameter | Noninfected by hookworm | Infected by hookworm | All | P value |
|---|---|---|---|---|
| N | 1,450 | 288 | 1,738 | |
| Age | 9.82 ± 2.19 | 9.88 ± 2.25 | 9.83 ± 2.20 | 0.654 |
| % Inflammation | 37.7 (N = 538) | 37.2 (N = 109) | 37.8 (N = 647) | 0.894 |
| Anthropometric status | ||||
| WAZ (only for < 10 years) | −1.88 ± 0.93 (N = 783) | −1.81 ± 0.93 (N = 155) | −1.87 ± 0.93 (N = 938) | 0.364 |
| % WAZ < −2SD | 31.0 (N = 243) | 34.1 (N = 53) | 31.5 (N = 938) | |
| % WAZ < −3SD | 11.8 (N = 93) | 10.3 (N = 16) | 11.6 (N = 109) | |
| HAZ | −1.81 ± 1.05 | −1.83 ± 1.09 | −1.81 ± 1.06 | 0.691 |
| % HAZ < −2SD | 28.6 (N = 416) | 30.5 (N = 88) | 28.9 (N = 503) | |
| % HAZ < −3SD | 13.1 (N = 190) | 13.9 (N = 40) | 13.2 (N = 230) | |
| BAZ | −1.50 ± 0.89 | −1.44 ± 0.86 | −1.49 ± 0.89 (N = 1,738) | 0.257 |
| % BAZ < −2SD | 27.8 (N = 403) | 24.3 (N = 70) | 27.2 (N = 471) | |
| % BAZ < −3SD | 0.0 (N = 1) | 0.0 (N = 0) | 0.0 (N = 1) | |
| Micronutrient status | ||||
| Hb (g/L) | 124.47 ± 9.2 | 122.33 ± 11.2 | 124.43 ± 9.6 (N = 1,738) | < 0.001 |
| % Anemia | 14.3 (N = 207) | 20.5 (N = 59) | 15.3 (N = 1,738) | < 0.01 |
| % Severe anemia | 0.00 (N = 0) | 0.01 (N = 2) | 0.01 (N = 2) | < 0.01 |
| FER*† (μg/L) | 80.83 ± 37.88 | 58.65 ± 29.61 | 77.13 ± 37.55 | < 0.001 |
| % FER* < 15 μg/L | 0.6 (N = 9) | 3.1 (N = 9) | 1.1 (N = 18) | < 0.01 |
| TfR† (mg/L) | 8.65 ± 2.33 | 9.42 ± 3.84 | 8.78 ± 2.66) | < 0.001 |
| % TfR > 8.3 mg/L | 49.9 (N = 711) | 56.3 (N = 161) | 50.9 (N = 872) | < 0.05 |
| % ID‡ total | 50.0 (N = 714) | 56.6 (N = 162) | 51.1 (N = 876) | < 0.05 |
| % ID‡ with anemia | 7.9 (N = 113) | 15.7 (N = 45) | 9.2 (N = 102) | < 0.05 |
| Body iron (mg/kg) | 6.77 ± 1.96 | 5.23 ± 2.85 | 6.51 ± 2.20 | < 0.001 |
| % Body iron < 0 | 0.7 (N = 10) | 6.7 (N = 19) | 1.7 (N = 29) | < 0.001 |
| % Body iron < 4 | 6.8 (N = 99) | 24.7 (N = 71) | 9.8 (N = 170) | < 0.001 |
| RBP* (μmol/L) | 1.59 ± 0.43 | 1.54 ± 0.43 | 1.58 ± 0.43 | 0.074 |
| % Marginal VA status§ | 8.1 (N = 116) | 10.8 (N = 31) | 8.6 (N = 147) | 0.132 |
| % Zinc deficiency‡‡ | 91.0 (N = 1,093) | 92.5 (N = 222) | 91.26 (N = 1,315) | 0.455 |
| Cognitive scores (raw score adjusted by age) | ||||
| Picture completion | 8.12 ± 4.7 | 7.58 ± 4.48 | 8.03 ± 4.67 | < 0.05 |
| Block design | 14.9 ± 9.82 | 13.14 ± 9.32 | 14.6 ± 9.76 | < 0.001 |
| Raven progressive test | 17.46 ± 4.89 | 16.87 ± 4.75 | 17.34 ± 4.87 | < 0.05 |
| Socioeconomic status of household (on a subgroup N = 454) | ||||
| Income§§ ($/year/household) | 1,825 (375, 4,290) | 1,672 (262, 2,940) | 1,815 (375, 4,147) | < 0.05 |
| % No or informal schooling (caregiver) | 15.3 (N = 60) | 20.0 (N = 10) | 15.8 (N = 70) | 0.819 |
| % Primary school (caregiver) | 61.3 (N = 241) | 54.0 (N = 27) | 60.5 (N = 268) | |
| % Secondary school (caregiver) | 23.4 (N = 92) | 26.0 (N = 50) | 23.7 (N = 105) | |
BAZ = BMI-for-age z-score; BMI = body mass index; FER = ferritin; HAZ = height-for-age z-score; Hb = hemoglobin; ID = iron deficiency; RBP = retinol-binding protein; SD = standard deviation; TfR = transferrin receptor; UIC = urinary iodine concentration; VA = vitamin A; VAD = vitamin A deficiency; WAZ = weight-for-age z-score. Results are mean ± SD, unless otherwise stated.
*
Corrected for inflammation.
†
Geometric mean ± SD.
‡
Based on FER* < 15 μg/L and/or TfR 0.8.3 mg/L.
§
0.7 ≤ RBP* < 1.05 μmol/L.
‡‡
Serum zinc < 9.9 μmol/L for age 4–9 years, < 10.1 μmol/L for girls ≥ 10 years of age, < 10.7 μmol/L for boys ≥ 10 years of age.
§§
Median (10th; 90th).