The relationship between inherited blood disorders and measures of iron status among young children in Kenya Open Access

Derby, Kiersten Smith (2013)

Permanent URL: https://etd.library.emory.edu/concern/etds/dv13zt44h?locale=en%5D
Published

Abstract

Abstract:

Background: Inherited blood disorders may influence iron indicators, which would have implications in areas with high burden of disease.

Objective: To determine if there is an association between inherited blood disorders and iron biomarkers.

Design: We conducted a population-based, cross-sectional survey of 854 children aged 6-35 months in western Kenya. Participants were tested for sickle cell, α-thalassemia, and G6PD deficiency. Ferritin, transferrin receptor (TfR), and zinc protoporphyrin (ZP) were measured, and TfR/ferritin index was calculated. Linear regression, adjusting for sociodemographic characteristics, malaria, and inflammation, was used to assess the association between blood disorders and iron biomarkers.

Results: Inherited blood disorders were common; 18.7% had sickle cell disease or trait, 48.0% had abnormal α-thalassemia genotype, and 6.8% had G6PD deficiency. The percentage of the population with abnormal iron biomarkers varied by indicator, ranging from 19.2% according to ferritin < 12 ug/L to 97.8% using ZP > 80 μmol/mol. Mean unadjusted TfR was highest among children with HbSS genotype compared to HbAS and HbAA (ANOVA p<0.0001). Mean unadjusted ZP was higher among boys with normal genotype compared to those with G6PD deficiency (p=0.02). In multivariate analysis, G6PD deficiency was an independent predictor of ZP among boys (β-coefficient = -0.17, p=0.04). There was interaction between sickle cell and malaria (p=0.01); malaria was a predictor of ZP among children without sickle cell, but not a predictor of ZP among those with sickle cell.

Conclusions: In areas with high prevalence of inherited blood disorders, genotypic differences may independently affect iron biomarkers, particularly TfR and ZP.

Table of Contents:
Thesis documents

Thesis body and references...10-23
Thesis figures and tables...24-30

Appendices

Appendix 1: Questionnaire...31-54
Appendix 2: Expanded literature review of key manuscripts...55-59
Appendix 3: Distribution plots of iron indicators: Pre- and post-log transformation...60-62
Appendix 4: Tables assessing confounding and interaction...63-68

a) ZP and Sickle Cell Trait/Disease
b) TfR and Sickle Cell Trait/Disease
c) SF and Sickle Cell Trait/Disease
d) Index and Sickle Cell Trait/Disease
e) TfR and alpha-thalassemia
f) ZP and G6PD deficiency among boys

Appendix 5: Multiple linear regression models...69-83

a) ZP and Sickle Cell Trait/Disease