Iron Deficiency Anemia, Not Iron Deficiency, Is Associated with Reduced Attention in Healthy Young Women.

Rebecca Cook,Cheyne Donges,Hoi Cheng,Helen Parker,Manohar Garg,Janet Franklin,Eka Cox,Helen O’Connor,Katharine Steinbeck,Kieron Rooney,Nicholas O’Dwyer

doi:10.3390/nu9111216

Abstract

Women of reproductive age are at increased risk for iron deficiency (ID) and iron deficiency anemia (IDA), with both implicated in decreased cognitive function (CF). Obesity may complicate this association via inflammatory-mediated ferritin elevation. This cross-sectional study examined the association between hematological iron status (iron replete (IR), ID or IDA) and CF in healthy, young (18–35 years) women of normal-weight (NW: BMI 18.5– 24.9 kg/m2) or obese-weight (OB: BMI >30 kg/m2). Participants completed a validated, computer-based cognition assessment evaluating impulsivity, attention, information processing, memory and executive function; CF reported as z-scores (mean ± SD). Iron status and CF were compared between groups via ANOVA, with adjustment for potential confounders (BMI, physical activity, C-reactive protein) via ANCOVA. A total of 157 NW and 142 OB women (25.8 ± 5.1 years) participated. Prevalence of ID and IDA were 14% and 6% respectively, with no significant difference between NW and OB groups. Women with IDA scored significantly lower on attention (although within normal range; ±1 z-score), compared to ID (IDA: −0.75 ± 1.89; ID: 0.53 ± 1.37; p = 0.004) but not IR (0.03 ± 1.33, p = 0.21) groups; there were no significant differences between ID and IR groups (p = 0.34). Adjustment for confounders did not significantly alter these results. In conclusion, women with IDA showed significantly reduced attention compared to women with ID.

Highlights

Iron is an essential nutrient and has a number of key roles in the body including erythropoiesis and oxygen transportation, energy production, enzyme synthesis, and immune function [1]
Data reported as mean ± SD. * p-Value for continuous variables: unpaired t-test, NW vs. OB. p-Value for categorical variables: Chi-square test, NW vs. OB. ** Ferritin corrected for inflammatory status (CRP ≥ 5 mg/L; α1GP > 1.0 mg/L) [28]
The cognitive function of the three groups based on iron status (IR, iron deficiency (ID) and iron deficiency anemia (IDA)) was assessed across five domains: impulsivity, attention, information processing, memory and executive function

Summary

Introduction

Iron is an essential nutrient and has a number of key roles in the body including erythropoiesis and oxygen transportation, energy production, enzyme synthesis, and immune function [1]. Iron deficiency (ID), including its more severe form iron deficiency anemia (IDA), is the most prevalent single nutrient deficiency worldwide, affecting both developed and developing countries [4]. A recent (2013) systematic review in women of reproductive age [10] examined the relationship between iron status and cognitive function, and whether a change in iron status affects cognitive performance via iron supplementation. Lower cognitive performance was reported in those with IDA or ID compared to iron replete (IR) women in four out of eight studies, across various psychometric tasks measuring attention, memory, learning, intelligence and arithmetic scores. Seven out of 10 studies reported improved cognition after iron supplementation intervention

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