Microcytosis is associated with low cognitive outcomes in healthy 2-year-olds in a high-resource setting. Issue 5 (13th September 2017)

• Record Type: Journal Article
• Authors: McCarthy, Elaine K.; Kiely, Mairead E.; Hannon, Geraldine; Ahearne, Caroline; Kenny, Louise C.; Hourihane, Jonathan O'B.; Irvine, Alan D.; Murray, Deirdre M.
• Is Part Of: British journal of nutrition. Volume 118:Issue 5(2017)
• Page Start: 360
• Page End: 367
• Publication Date: 2017-09-13
• Subjects: Bayley Scales of Infant and Toddler Development, -- Microcytosis, -- Serum ferritin, -- Neurodevelopment, -- Cognition; Nutrition -- Periodicals; 572.4
• DOI: 10.1017/S0007114517001945
• Languages: English
• ISSNs: 0007-1145

Abstract

Abstract: Fe deficiency in early childhood is associated with long-term consequences for cognitive, motor and behavioural development; however explorations in healthy children from low risk, high-resource settings have been limited. We aimed to explore associations between Fe status and neurodevelopmental outcomes in low risk, healthy 2-year-olds. This study was a secondary analysis of a nested case–control subgroup from the prospective, maternal-infant Cork Babies after Screening for Pregnancy Endpoints: Evaluating the Longitudinal Impact using Neurological and Nutritional Endpoints (BASELINE) Birth Cohort Study. At 2 years, serum ferritin, Hb and mean corpuscular volume (MCV) were measured and neurodevelopment was assessed using the Bayley Scales of Infant and Toddler Development ( n 87). Five children had Fe deficiency (ferritin <12 µg/l) and no child had Fe deficiency anaemia (Hb<110 g/l+ferritin<12 µg/l). Children with microcytosis (MCV<74 fl, n 13) had significantly lower mean cognitive composite scores (88·5 (sd 13·3) v . 97·0 (sd 7·8), P =0·04, Cohen's d effect size=0·8) than those without microcytosis. The ferritin concentration which best predicted microcytosis was calculated as 18·4 µg/l (AUC=0·87 (95% CI 0·75, 0·98), P <0·0001, sensitivity 92 %, specificity 75 %). Using 18·5 µg/l as a threshold, children with concentrations <18·5 µg/l had significantly lower mean cognitive composite scores (92·3 (sd 10·5) v . 97·8 (sd 8·1), P =0·012, Cohen's d effect size=0·6) compared with those with ferritin ≥18·5 µg/l. All associations were robust after adjustment for potential confounding factors. Despite a low prevalence of Fe deficiency using current diagnostic criteria in this healthy cohort, microcytosis was associated with lower cognitive outcomes at 2 years. This exploratory study emphasises the need for re-evaluation of the diagnostic criteria for Fe deficiency in young children, with further research in adequately powered studies warranted.