Effects of iron intake on neurobehavioural outcomes in African children: a systematic review and meta-analysis of randomised controlled trials.

Iron deficiency and developmental delay are common in African children. While experimental studies indicate an important role of iron in brain development, effects of iron on child development remain unclear. We aimed to evaluate the effects of iron supplementation or fortification on neurobehavioural outcomes in African children and further summarise these effects in children living in non-African countries for comparison. We searched PubMed, EMBASE, PsycINFO, Scopus and Cochrane Library for studies published up to 9 March 2021. We included randomised controlled trials (RCTs) evaluating effects of iron supplementation or fortification on neurobehavioural outcomes in children. Due to heterogeneity in study methods, we analysed the studies qualitatively and only seven RCTs with 11 arms were meta-analysed. We identified 2155 studies and included 34 studies (n=9808) in the systematic review. Only five studies (n=1294) included African children while 29 (n=8514) included children living in non-African countries. Of the five African studies, two (n=647) reported beneficial effects of iron supplementation on neurobehavioural outcomes in anaemic children while three (n=647) found no beneficial effects. Of 29 studies in children living in non-African countries, nine (n=2925) reported beneficial effects of iron supplementation or fortification on neurobehavioural outcomes, seven (n=786) reported beneficial effects only in children who had iron deficiency, iron deficiency anaemia or anaemia while 13 (n=4803) reported no beneficial effects. Meta-analysis of seven studies (n=775) in non-African countries showed no beneficial effects of iron supplementation on cognitive or motor development in children. There are few studies in African children despite the high burden of iron deficiency and developmental delay in this population. Evidence on the effects of iron supplementation on neurobehavioural outcomes remains unclear and there is need for further well-powered studies evaluating these effects in African populations. CRD42018091278 (20/03/2018).