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Table 6 Summary of results for multiple micronutrient fortification in children

From: Micronutrient fortification of food and its impact on woman and child health: a systematic review

Outcome/quality of evidence Combined effect   Age groups Country Number of micronutrients used Duration of fortification
General/healthy population Deficient population Infants Preschool and school-going children Low- and lower middle-income countries Upper middle- and higher-income countries 5 or less 6 to 12 More than 12 Less than 6 months 6 to 11 months 12 months or more
Hemoglobin levels SMD: 0.75 (95% CI: 0.41, 1.08) SMD: 0.72 (95% CI: 0.37, 1.07) SMD: 1.06 (95% CI: 0.75, 1.38) SMD: 1.05 (95% CI: 0.48, 1.63) SMD: 0.45 (95% CI: 0.12, 0.79) SMD: 0.50 (95% CI: 0.21, 0.78) SMD: 1.25 (95% CI: 0.45, 2.06) SMD: 1.50 (95% CI: -0.23, 3.23) SMD: 0.51 (95% CI: 0.24, 0.78) SMD: 0.71 (95% CI: 0.32, 1.09) SMD: 0.07 (95% CI: -0.17, 0.31) SMD: 1.05 (95% CI: 0.55, 1.56) SMD: 0.52 (95% CI: 0.07, 0.98)
Quality of evidence: Moderate   13 studies 2,876 participants 1 study 175 participants 7 studies 1,508 participants 7 studies 1,543 participants 8 studies 1,769 participants 6 studies 1,282 participants 4 studies 747 participants 6 studies 1,449 participants 4 studies 855 participants 2 studies 310 participants 8 studies 2,025 participants 4 studies 716 participants
Serum ferritin levels SMD: 0.37 [0.13, 0.62) SMD: 0.37 (95% CI: 0.13, 0.62) No studies identified SMD: 0.43 (95% CI: 0.17, 0.68) SMD: 0.06 (95% CI: -0.17, 0.29) SMD: 0.47 (95% CI: 0.14, 0.80) SMD: 0.18 (95% CI: -0.03, 0.40) SMD: 0.45 (95% CI: 0.00, 0.90) SMD: 0.62 (95% CI: 0.18, 1.06) SMD: 0.17 (95% CI: -0.16, 0.50) SMD: 0.45 (95% CI: 0.00, 0.90) SMD: 0.48 (95% CI: 0.07, 0.89) SMD: 0.20 (95% CI: -0.23, 0.64)
Quality of evidence: Low   7 studies 1,848 participants   6 studies 1,547 participants 1 study 301 participants 4 studies 1,380 participants 3 studies 468 participants 1 study 79 participants 2 studies 748 participants 4 studies 1,021 participants 1 study 79 participants 3 studies 1,049 participants 3 studies 7,20 participants
Serum zinc levels SMD: 0.08 [−0.02, 0.19) SMD: 0.08 (95% CI: -0.02, 0.19) No studies identified SMD: 0.04 (95% CI: -0.10, 0.17) SMD: 0.17 (95% CI: 0.04, 0.30) SMD: 0.12 (95% CI: 0.01, 0.23) SMD: -0.02 (95% CI: -0.26, 0.23) SMD: -0.12 (95% CI: -0.75, 0.51) SMD: 0.13 (95% CI: -0.02, 0.29) SMD: 0.06 (95% CI: -0.05, 0.17) SMD: 0.31 (95% CI: 0.06, 0.57) SMD: 0.06 (95% CI: -0.09, 0.21) SMD: 0.02 (95% CI: -0.11, 0.15)
Quality of evidence: Moderate   11 studies 2,972 participants   7 studies 1,780 participants 4 studies 1,192 participants 7 studies 1,960 participants 4 studies 1,012 participants 2 studies 232 participants 4 studies 1,820 participants 5 studies 920 participants 1 study 223 children 6 studies 1,128 participants 4 studies 1,221 participants
Serum retinol levels SMD: -0.05 [−0.23, 0.13) SMD: 0.05 (95% CI: -0.23, 0.13) No studies identified SMD: 0.04 (95% CI: -0.22, 0.30) SMD: -0.21 (95% CI: -0.34, -0.07) SMD: -0.06 (95% CI: -0.25, 0.14) SMD: 0.01 (95% CI: -0.63, 0.64) SMD: -0.28 (95% CI: -0.45, -0.11) SMD: -0.03 (95% CI: -0.33, 0.27) SMD: 0.02 (95% CI: -0.27, 0.31) No studies identified SMD: -0.08 (95% CI: -0.29, 0.13) SMD: 0.03 (95% CI: -0.37, 0.43)
Quality of evidence: Low   8 studies 1,927 participants   4 studies 964 participants 4 studies 963 participants 6 studies 1,320 participants to 2 studies 607 participants 2 studies 533 participants 5 studies 878 participants 3 studies 516 participants   3 studies 1,676 participants 3 studies 251 participants
Effect on anemia RR: 0.55 (95% CI: 0.42, 0.71) RR: 0.59 (95% CI: 0.46, 0.75) RR: 0.20 (95% CI: 0.10, 0.40) RR: 0.59 (95% CI: 0.50, 0.70) RR: 0.45 (95% CI: 0.22, 0.89) RR: 0.50 (95% CI: 0.37, 0.67) RR: 0.69 (95% CI: 0.41, 1.15) No studies identified No studies identified No studies identified RR: 0.77 (95% CI: 0.43, 1.36) RR: 0.54 (95% CI: 0.36, 0.83) RR: 0.50 (95% CI: 0.33, 0.77)
Quality of evidence: Low   9 studies 2,880 participants 1 study 175 participants 5 studies 1809 participants 5 studies 1246 participants 7 studies 2,229 participants 3 studies 826 participants     1 study 223 children 4 studies 1,097 participants 5 studies 1,726 participants
Effect on vitamin A deficiency RR: 0.90 (95% CI: 0.76, 1.06) RR: 0.90 (95% CI: 0.76, 1.06) No studies identified RR: 0.85 (95% CI: 0.69, 1.03) RR: 1.02 (95% CI: 0.76, 1.38) RR: 0.88 (95% CI: 0.73, 1.07) RR: 0.95 (95% CI: 0.66, 1.36) No studies identified No studies identified No studies identified No studies identified RR: 0.85 (95% CI: 0.71, 1.03) RR: 1.14 (95% CI: 0.76, 1.71)
Quality of evidence: Low   6 studies 2,036 participants   3 studies 687 participants 3 studies 1349 participants 4 studies 1,391 participants 2 studies 645 participants      3 studies 1,308 participants 3 studies 728 participants
Height-for-age Z-score SMD: 0.13 (95% CI: -0.04, 0.29) SMD: 0.12 (95% CI: -0.09, 0.32) SMD: 0.22 (95% CI: -0.04, 0.47) SMD: 0.26 (95% CI: 0.12, 0.40) SMD: -0.01 (95% CI: -0.21, 0.20) SMD: 0.09 (95% CI: -0.17, 0.34) SMD: 0.18 (95% CI: 0.02, 0.34) SMD: -0.00 (95% CI: -0.19, 0.18) SMD: 0.11 (95% CI: -0.12, 0.34) SMD: 0.18 (95% CI: -0.07, 0.42) SMD: 0.01 (95% CI: -0.13, 0.15) SMD: 0.11 (95% CI: -0.12, 0.34) SMD: 0.39 (95% CI: 0.24, 0.55)
Quality of evidence: Low   6 studies 1,853 participants 2 studies 245 participants 5 studies 1,083 participants 3 studies 1,009 participants 5 studies 1,485 participants 3 studies 607 participants 2 studies 624 participants 1 study 288 participants 5 studies 1,180 participants 5 studies 1,170 participants 1 study 288 participants 2 studies 634 participants
Weight-for-age Z-score SMD: -0.12 (95% CI: -0.43, 0.20) SMD: 0.05 (95% CI: -0.09, 0.18) SMD: 0.18 (95% CI: -0.14, 0.49) SMD: -0.28 (95% CI: -0.85, 0.29) SMD: 0.09 (95% CI: -0.16, 0.33) SMD: 0.10 (95% CI: -0.13, 0.32) SMD: -0.48 (95% CI: -1.45, 0.49) SMD: -0.02 (95% CI: -0.28, 0.24) SMD: -0.03 (95% CI: -0.26, 0.20) SMD: -0.22 (95% CI: -0.76, 0.33) SMD: -0.25 (95% CI: -0.90, 0.41) SMD: 0.06 (95% CI: -0.09, 0.21) SMD: -0.68 (95% CI: -2.79, 1.42)
Quality of evidence: Low   6 studies 1,853 participants 2 studies 245 participants 5 studies 1083 participants 3 studies 1,009 participants 5 studies 1,485 participants 3 studies 607 participants 2 studies 624 participants 1 study 288 participants 5 studies 1,180 participants 5 studies 1,170 participants 1 study 288 participants 2 studies 634 participants
Weight-for-height Z-score SMD: -0.11 (95% CI: -0.40, 0.17) SMD: -0.17 (95% CI: -0.56, 0.22) SMD: -0.56 (95% CI: -1.42, 0.31) SMD: 0.08 (95% CI: -0.06, 0.21) SMD: -0.39 (95% CI: -1.06, 0.28) SMD: 0.07 (95% CI: -0.07, 0.20) SMD: -0.40 (95% CI: -1.17, 0.38) SMD: -0.01 (95% CI: -0.29, 0.26) SMD: -0.14 (95% CI: -0.37, 0.09) SMD: -0.16 (95% CI: -0.66, 0.34) SMD: -0.10 (95% CI: -0.75, 0.56) SMD: -0.23 (95% CI: -0.64, 0.18) SMD: 0.18 (95% CI: 0.02, 0.34)
Quality of evidence: Low   6 studies 1,853 participants 2 studies 245 participants 5 studies 1,083 participants 3 studies 1,009 participants 5 studies 1,485 participants 3 studies 607 participants 2 studies 624 participants 1 study 288 participants 5 studies 1,180 participants 5 studies 1,170 participants 1 study 288 participants 2 studies 634 participants
  1. Estimates in BOLD show significant impacts. CI, confidence intervals; RR: relative risk; SMD: standard mean difference.