Protein supplementation delivered alone or in combination with presumptive azithromycin treatment for enteric pathogens did not improve linear growth in Bangladeshi infants: results of a cluster-randomized controlled trial.

BACKGROUND

Protein requirements established for healthy populations may be insufficient to support healthy growth in infants consuming largely cereal-based complementary foods and frequently exposed to enteric pathogens.

OBJECTIVES

This study aimed to assess independent and combined effects of protein supplementation and antibiotic treatment on linear growth of infants aged 6-12 mo.

METHODS

We conducted a 2 × 4 factorial cluster-randomized trial in northwestern Bangladesh, allocating 566 clusters to masked azithromycin (10 mg/kg × 3 d) or placebo at 6 and 9 mo of age and unmasked delivery of an egg white protein-rich blended food supplement (250 kcal; 10 g added protein), a rice-based isocaloric supplement, egg, or nutrition education from 6 to 12 mo. We measured length at 6 and 12 mo. For this cluster-level intention-to-treat analysis of the 2 × 2 antibiotic and protein interventions, we used multiple linear or log-binomial regression with generalized estimating equations to assess changes in length-for-age z (LAZ) score and stunting (LAZ < -2), respectively.

RESULTS

We enrolled 2055 infants (283 clusters) and included 1821 infants (281 clusters) with complete anthropometry data at 6 and 12 mo in our analysis. There were no significant interactions between the protein and antibiotic interventions for any outcomes. Independently, protein supplement did not improve LAZ (β: 0.05; 95% CI: 0.00, 0.11; P = 0.07) or reduce stunting (prevalence ratio: 1.12; 95% CI: 0.85, 1.49; P = 0.41) compared with the isocaloric supplement. The antibiotic intervention had no effect on LAZ (β: -0.05; 95% CI: -0.11, 0.01; P = 0.09) or stunting (prevalence ratio: 0.99; 95% CI: 0.75, 1.31; P = 0.96), relative to the placebo.

CONCLUSIONS

Supplementation to increase intakes of high-quality protein, provided with or without presumptive treatment for enteric pathogens, did not improve linear growth from 6 to 12 mo of age. This trial was registered at clinicaltrials.gov as NCT03683667.