From: Micronutrient fortification of food and its impact on woman and child health: a systematic review
 |  | Iodine fortification | ||
---|---|---|---|---|
Outcome/quality of evidence | Combined effect | Â | ||
Serum thyroxin levels | SMD: 0.45 (95% CI: -1.15, 2.06) | 2 studies 1,131 participants reported this outcome. The studies were conducted in Africa on school-going children. | ||
Quality of evidence: Low | Â | |||
Urinary iodine concentrations | SMD: 6.39 (95% CI: 2.69, 10.08) | 2 studies 1,016 participants reported this outcome. The studies were conducted in Africa on school-going children. | ||
Quality of evidence: Moderate | Â | |||
 |  | Vitamin A fortification | ||
Outcome/quality of evidence | Combined effect | Â | ||
Hemoglobin levels | SMD: 0.48 (95% CI: 0.07, 0.89) | 2 studies with1,538 participants reported the outcome. The study by Zhang et al.[132] used four different comparison groups. The first group received low amounts of vitamin A-fortified biscuits for 9 months daily. The second group received high amount of vitamin A-fortified biscuits for 3 months daily. The third group received very high amounts of vitamin A-fortified biscuits for 3 months weekly. The standard mean differences for the three groups were 0.73 (95% CI: 0.42, 1.04), 0.62 (95% CI: 0.38, 0.85) and 0.63 (95% CI: 0.38, 0.88) respectively. | ||
Quality of evidence: Low | ||||
Serum vitamin A concentration | SMD: 0.61 (95% CI: 0.39, 0.83) | 3 studies with 2,362 participants reported the outcome. The study by Zhang et al.[132] used four different comparison groups as explained in comments for hemoglobin levels. The standard mean differences for the three groups were 0.52 (95% CI: 0.21, 0.82), 0.73 (95% CI: 0.49, 0.97) and 0.44 (95% CI: 0.22, 0.66). | ||
Quality of evidence: Low | ||||
Vitamin A deficiency | RR: 0.39 (95% CI: 0.09, 1.74) | 2 studies with 1,465 participants reported the outcome. The study by Zhang et al.[132] showed positive impacts in reducing vitamin A deficiency whereas the study by Solon et al.[110] showed negative impacts. The latter used monosodium glutamate for vitamin A fortification and the quantity of vitamin A used was much less than that used by Zhang et al. | ||
Quality of evidence: Moderate | ||||
Calcium and vitamin D fortification | ||||
Outcome/quality of evidence | Combined effect | Calcium only | Vitamin D only | Calcium and vitamin D |
Serum parathyroid hormone levels | SMD: -0.40 (95% CI: -0.56, -0.24) | SMD: -0.28 (95% CI: -0.50, -0.06) | No studies identified | SMD: -0.52 (95% CI: -0.74, -0.29) |
Quality of evidence: Low | 2 studies 317 participants | 2 studies 327 participants | ||
Serum vitamin D levels | SMD: 1.23 (95% CI: 0.35, 2.11) | SMD: -0.15 (95% CI: -0.41, 0.10) | SMD: 1.76 (95% CI: 0.37, 3.15) | SMD: 1.58 (95% CI: 1.28, 1.87) |
Quality of evidence: Moderate | 1 study 233 participants | 2 studies 651 participants | 1 study 235 participants | |
Serum calcium levels | SMD: -0.40 (95% CI: -0.59, -0.20) | SMD: -0.30 (95% CI: -0.56, -0.04) | No studies identified | SMD: -0.50 (95% CI: -0.76, -0.24) |
Quality of evidence: Low | 1 study 231 participants | Â | 1 study 235 participants |