Effect of iron intervention on growth during gestation, infancy, childhood, and adolescence: a systematic review with meta-analysis

Abstract

To evaluate the effect of iron intervention on physical growth in fetuses, infants, children, and adolescents up to 18 years of age, a systematic review with meta-analysis of randomized controlled trials (RCTs) was conducted. Structured electronic searches were conducted to February 2010 using MEDLINE, Embase, and the Cochrane Library databases. RCTs that included iron-fortified foods, iron-fortified formula, or iron supplements and in which height, weight, mid-arm circumference (MAC), head circumference, birth weight, or length of gestation was evaluated were analyzed for inclusion. In total, 21 RCTs in infants, children, and adolescents and 7 studies in pregnant women met the inclusion criteria. The overall pooled result (random-effects model) showed no significant effects of iron intervention on any of the parameters measured. To accommodate wide heterogeneity, studies were stratified according to dose of iron, duration of intervention, age, and baseline iron status. However, only doses of 40-66 mg of supplemental iron and intervention in children ≥ 6 years of age showed a slight but significant association with weight and MAC.

Safety and benefits of antenatal oral iron supplementation in low‐income countries: a review

“…This effect on birth weight is small compared to the normal variability in birth weight (the usual standard deviation is ~450 g) and corroborates findings from other recent meta‐analyses that found no effect on birth weight (Vucic et al , 2013) or an increase of only 41 g (Haider et al , 2013). …”

Screening and Routine Supplementation for Iron Deficiency Anemia: A Systematic Review

“…23,26,28,30 We found no evidence of important or clear benefit in growth outcomes, which is consistent with the findings of a recent meta-analysis of 21 randomized controlled trials that included studies from any country. 18 Although the study findings are not consistent, the evidence from 10 trials of iron supplementation in children indicates no benefit in terms of incidence of IDA, anemia, or hemoglobin; the findings were inconsistent regarding incidence of iron deficiency and serum ferritin concentrations. [22][23][24][25][26][27][28][29][30][31][32] Some of the variation in findings may have been due to inadequate sample sizes for specific outcomes.…”

“…16,17 Because the previous research focused on systematic reviews and key studies of treatments for IDA, we also searched the reference lists of systematic reviews [18][19][20] to identify any additional, relevant studies published before 1996.…”

Nutrition During Pregnancy, Lactation and Early Childhood and its Implications for Maternal and Long-Term Child Health: The Early Nutrition Project Recommendations

“…In addition, systematic reviews of published data were performed on the impact of paternal and maternal body mass index (BMI) on offspring obesity risk [12], on effects of dietary and lifestyle interventions in pregnant women with a normal BMI [13] and on effects of protein concentration in infant formula on growth and later obesity risk [14]. We also considered the data of systematic reviews on the effects of growth in term infants and later obesity risk [15], the effects of growth in preterm infants on later health [16], on the age of introduction of complementary foods [17], and on the pre-and postnatal effects of dietary iron [18] and of long-chain polyunsaturated fatty acids (LC-PUFA) [19]. Moreover, we performed systematic reviews of published systematic reviews on nutritional interventions or exposures in pregnancy [19] and in infants and young children aged up to 3 years [20] that describe effects on subsequent overweight, obesity and body composition.…”