Lower iron stores were associated with suboptimal gross motor scores in infants at 3–7 months

Abstract

Aim: To investigate associations between iron status and gross motor scores in infants aged 3–7 months. Methods: In a prospective study, 252 infants aged 3–7 months were examined using the age-standardised Alberta Infant Motor Scale (AIMS) prior to analysing iron status in 250 infants. Combined AIMS and ferritin results were assessed in 226 infants, whereas AIMS and reticulocyte haemoglobin (ret-Hb) results were obtained for 61 infants. We used logistic regressions and receiver operator characteristics to analyse our data. Results: With AIMS z-score <10th percentile as outcome measure, optimal cut-off value for ferritin was 51 μg/L (sensitivity 86%, specificity 81%) and 28 pg for ret-Hb (sensitivity 86%, specificity 85%). The area under the curve for ferritin and ret-Hb was 0.886 and 0.896, respectively (n = 61). Ferritin <51 μg/L predicted an AIMS z-score <10th percentile in a logistic regression (OR 3.3, 95% CI 1.4–7.5, p = 0.006, n = 226). Six of 14 (43%) infants with ret-Hb <28 pg scored <10th percentile on AIMS compared to 1/47 (2.1%) infants with ret-Hb ≥28 μg/L (Exact, p < 0.001). Conclusion: Reticulocyte haemoglobin of <28 pg and ferritin <51 μg/L were associated with suboptimal gross motor scores in infants 3–7 months.