Effect of Docosahexaenoic Acid Supplementation vs Placebo on Developmental Outcomes of Toddlers Born Preterm: A Randomized Clinical Trial.

Importance: Intake of dietary docosahexaenoic acid (DHA) among toddlers is low. Supplementation may benefit developmental outcomes of toddlers who were born preterm.

Objective: To determine whether 6 months of daily DHA supplementation improves developmental outcomes of toddlers who were born preterm.

Design, Setting, and Participants: A randomized, fully masked, placebo-controlled trial was conducted from April 26, 2012, to March 24, 2017, at a large US pediatric academic center with 9 neonatal intensive care units. Children born at less than 35 weeks' gestation who were 10 to 16 months corrected age underwent 6 months of intervention. Of 2363 children assessed, 982 were eligible, 605 declined, and 377 enrolled and were randomized. Analyses were according to intent to treat.

Interventions: One-to-one allocation to receive daily microencapsulated DHA, 200 mg, and arachidonic acid (AA), 200 mg (DHA+AA), or microencapsulated corn oil (placebo).

Main Outcomes and Measures: The primary outcome specified a priori was Bayley Scales of Infant and Toddler Development, third edition (Bayley-III), cognitive composite score at 16 to 22 months corrected age. Secondary outcomes were Bayley-III language and motor composite scores and Infant Behavior Questionnaire-Revised and Early Childhood Behavior Questionnaire effortful control and activity level scores. Subgroup analyses defined a priori were by income, sex, and birth weight.

Results: Among 377 children randomized and included in the analysis (182 girls and 195 boys; median corrected age, 15.7 months), 338 children (89.7%) had complete data on the primary outcome. Bayley-III cognitive scores did not differ between the DHA+AA and placebo groups (difference in change, 0.5 [95% CI, -1.8 to 2.8]; effect size, 0.05; P = .66). Assignment to the DHA+AA group had a small to medium negative effect on Bayley-III language scores among children with lower birth weights (eg, a child with a birth weight of 1000 g assigned to receive DHA+AA experienced a 4.1-point relative decrease, while a child assigned to placebo did not; P = .03 for interaction). Supplementation had a similar negative effect on effortful control scores among children with annual household incomes greater than $35 000 (difference in change, -0.3 [95% CI, -0.4 to -0.1]; effect size, -0.37; P = .01). Bayley-III motor scores and activity level scores were unaffected.

Conclusions and Relevance: Daily supplementation with 200 mg of DHA and 200 mg of AA for 6 months resulted in no improvement in cognitive development and early measures of executive function vs placebo, and may have resulted in negative effects on language development and effortful control in certain subgroups of children. These findings do not support DHA supplementation in the second year of life for children who are born preterm.

Trial Registration: ClinicalTrials.gov Identifier: NCT01576783.