Micronutrient supplementation for adolescents
A total of 31 studies were included, of which 23 were conducted
in LMICs [30e59,76]. Studies evaluated the effectiveness of
iron, folic acid, vitamin A, vitamin D, vitamin C, calcium, zinc, and
multiple micronutrients supplementation to adolescent population.
Thirteen studies evaluated the impact of iron/iron folic acid supplementation alone, nine studies evaluated the impact
of iron/iron folic acid in combinationwith other micronutrients,
two studies evaluated the impact of multiple micronutrients
alone, two studies evaluated zinc supplementation while
five studies supplemented with calcium and vitamin D.
The intervention was mostly implemented in schools with the
exception of five community-based studies [27e31]. Most
studies evaluated the impact of micronutrient supplementation on adolescent girls except for nine studies that included
adolescent boys and girls.
Findings from moderate-quality evidence suggest an overall
significant reduction in anemia (as defined by study authors)
with iron/iron folic acid supplementation alone or in combination
with other micronutrient supplementation (RR: .69; 95%
CI: .62e.76; Figure 2). Subgroup analysis according to the delivery
settings suggests that school-based delivery significantly
reduced anemia (RR: .67; 95% CI: .60e.74) while evidence from
community-based delivery was underpowered. School-based
delivery of iron/iron folic acid supplementation alone or in
combination with other micronutrient supplementationwas also
associated with improved serum hemoglobin (mean difference
[MD]: 1.94 g/dl; 95% CI: 1.48e2.41), ferritin (MD: 3.80 mcg/L; 95%
CI: 2.00e5.59), and iron (MD: 6.97 mmol/L; 95% CI: .19e13.76).
Zinc supplementation led to improved serum zinc concentrations
(MD: .96 mcg/dl; 95% CI: .81e1.12) while calcium and
vitamin D supplementation did not have a clear impact on
vitamin D levels and parathyroid hormone. Gender-specific
subgroup analysis suggests significant improvements in both
genders; however, most of the studies were conducted on
adolescent girls.