Iron status and inherited haemoglobin disorders modify the effects of micronutrient powders on linear growth and morbidity among young Lao children in a double-blind randomised trial.

Sonja Y Hess,Supan Fucharoen,Maxwell A Barffour,Charles D Arnold,K Ryan Wessells,Kenneth H Brown,Sengchanh Kounnavong,Charles P Larson,Kanokwan Sanchaisuriya,Guy-Marino Hinnouho

doi:10.1017/s0007114519001715

Abstract

Some studies found that providing micronutrient powder (MNP) causes adverse health outcomes, but modifying factors are unknown. We aimed to investigate whether Fe status and inherited Hb disorders (IHbD) modify the impact of MNP on growth and diarrhoea among young Lao children. In a double-blind controlled trial, 1704 children of age 6–23 months were randomised to daily MNP (with 6 mg Fe plus fourteen micronutrients) or placebo for about 36 weeks. IHbD, and baseline and final Hb, Fe status and anthropometrics were assessed. Caregivers provided weekly morbidity reports. At enrolment, 55·6 % were anaemic; only 39·3 % had no sign of clinically significant IHbD. MNP had no overall impact on growth and longitudinal diarrhoea prevalence. Baseline Hb modified the effect of MNP on length-for-age (LAZ) (P for interaction = 0·082). Among children who were initially non-anaemic, the final mean LAZ in the MNP group was slightly lower (–1·93 (95 % CI –1·88, –1·97)) v. placebo (–1·88 (95 % CI –1·83, –1·92)), and the opposite occurred among initially anaemic children (final mean LAZ –1·90 (95 % CI –1·86, –1·94) in MNP v. –1·92 (95 % CI –1·88, –1·96) in placebo). IHbD modified the effect on diarrhoea prevalence (P = 0·095). Among children with IHbD, the MNP group had higher diarrhoea prevalence (1·37 (95 % CI 1·17, 1·59) v. 1·21 (95 % CI 1·04, 1·41)), while it was lower among children without IHbD who received MNP (1·15 (95 % CI 0·95, 1·39) v. 1·37 (95 % CI 1·13, 1·64)). In conclusion, there was a small adverse effect of MNP on growth among non-anaemic children and on diarrhoea prevalence among children with IHbD.

Highlights

Anaemia and deficiencies of Fe, iodine, Zn and vitamin A remain public health concerns in many low-income countries[1]
Attrition was similar across intervention groups, with the largest difference between groups occurring for end line anthropometry where micronutrient powder (MNP) had 82·3 % and placebo had 86·9 % follow-up, which resulted in a difference of 4·6 %
Among children enrolled in the two groups (n 1704), 1336 provided a venous blood sample at baseline for assessment of Fe status, and Inherited Hb disorders (IHbD) was assessed in 1412 children

Summary

Introduction

Anaemia and deficiencies of Fe, iodine, Zn and vitamin A remain public health concerns in many low-income countries[1]. A large percentage of the population in Southeast Asia has non-severe IHbD, such as the α-thalassaemia trait (20–30 %), the β-thalassaemia trait (3–9 %) and the Hb E trait (up to 60 %)(8,10) These latter milder forms of IHbD result from deletions or mutations in one or more, but not all, of the α- or β-globin alleles and often lead to only mild microcytosis, with or without anaemia[11]. There is a risk that the insufficient down-regulation of Fe absorption in Fe-replete individuals with asymptomatic types of IHbD, which are prevalent in the populations of Southeast Asia, may cause adverse health outcomes when consuming supplementary Fe in products like MNP

Objectives

Methods

Results

Conclusion