Effect of supplements on children’s IQ by adherence, BMI in pregnancy, mothers’ haemoglobin status in pregnancy, birth weight and sex
| Control (n=409) No (%) | Intervention (n=404) No (%) | Difference in means (95% CI) | P value* | Coefficient (95% CI)† | P value | |
| Adherence to supplements | ||||||
| Children, N | 409 (100) | 404 (100) | – | – | – | – |
| Children whose mothers adhered ≥95%, n (%) | 277 (67.7) | 265 (65.6) | – | – | – | – |
| Full-scale IQ, mean (SD) | 76.5 (13.6) | 78.4 (12.2) | 1.94 (−0.25 to 4.13) | 0.08 | 1.56 (−0.44 to 3.56) | 0.13 |
| Mothers who adhered <95%, n (%) | 132 (32.2) | 139 (34.4) | – | |||
| Full-scale IQ, mean (SD) | 76.1 (14.8) | 76.1 (12.3) | −0.06 (−3.30 to 3.19) | 0.97 | 0.40 (−2.47 to 3.27) | 0.78 |
| BMI in pregnancy | ||||||
| Children, N | 408 (100) | 403 (100) | – | – | ||
| Children whose mothers had BMI <18.5, n (%) | 126 (30.9) | 120 (29.8) | – | – | 0.22 | |
| Full-scale IQ, mean (SD) | 75.6 (13) | 76.3 (13) | 0.75 (−2.50 to 4.01) | 0.65 | 1.89 (−1.12 to 4.91) | |
| Children whose mothers had BMI ≥18.5, n (%) | 282 (69.1) | 283 (70.2) | – | – | – | |
| Full-scale IQ, mean (SD) | 76.7 (14.5) | 78.2 (12) | 1.41 (−0.78 to 3.61) | 0.21 | 0.92 (−1.05 to 2.89) | 0.36 |
| Haemoglobin (Hb) concentration during pregnancy | ||||||
| Children, N | 409 (100) | 404 (100) | – | – | ||
| Children whose mothers had Hb <11 g/dL, n (%) | 96 (23.5) | 88 (21.8) | – | – | ||
| Full-scale IQ, mean (SD) | 78 (15.1) | 77.8 (11.7) | −0.12 (−4.08 to 3.84) | 0.95 | 0.28 (−3.38 to 3.93) | 0.88 |
| Children whose mothers had Hb ≥11 g/dL, n (%) | 313 (76.5) | 316 (78.2) | – | – | ||
| Full-scale IQ, mean (SD) | 76 (13.6) | 77.6 (12.5) | 1.67 (−0.37 to 3.71) | 0.11 | 1.26 (−0.56 to 3.07) | 0.17 |
| Birth weight | ||||||
| Children weighed within 72 hours at birth, N | 398 (100) | 396 (100) | – | – | ||
| Children with birth weight <2500 g | 98 (24.6) | 71 (17.9) | – | – | ||
| Full-scale IQ, mean (SD) | 73.3 (15.1) | 75.4 (11.5) | 2.12 (−2.10 to 6.34) | 0.32 | 2.77 (−0.92 to 6.45) | 0.14 |
| Children with birth weight ≥2500 g | 300 (75.4) | 325 (82.1) | – | – | ||
| Full-scale IQ, mean (SD) | 77.5 (13.5) | 78.1 (12.4) | 0.55 (−1.48 to 2.49) | 0.59 | 0.51 (−1.35 to 2.37) | 0.59 |
| Children’s sex | ||||||
| Children, N | 409 | 404 | – | – | – | |
| Male, n (%) | 204 (49.9) | 208 (51.5) | – | – | – | |
| Full-scale IQ, mean (SD) | 80.4 (12.6) | 78.6 (12.1) | −1.75 (−4.15 to 0.64) | 0.15 | −0.76 (−2.99 to 1.46) | 0.50 |
| Female, n (%) | 203 (49.6) | 196 (48.5) | – | – | – | – |
| Full-scale IQ, mean (SD) | 72.3 (14.2) | 76.6 (12.4) | 4.25 (1.62 to 6.89) | <0.01‡ | 2.85 (0.53 to 5.17) | 0.02 |
*Unadjusted, derived from independent-samples t-test.
†Adjusted coefficients derived from linear regression models that included residence (rural vs rural), maternal literacy (cannot read vs can read easily or with difficulty), tester (categorical), HOME score (continuous) and children’s age in days as covariates.
‡Exact P value: 0.0016.
BMI, body mass index; HOME, Early Adolescent Home Observation Tool.