Mediation Analysis to Untangle Opposing Associations of High-Dose Docosahexaenoic Acid With IQ and Bronchopulmonary Dysplasia in Children Born Preterm

Maternal high-dose docosahexaenoic acid supplementation and neurodevelopment at 5 Years of preterm children

BACKGROUND & AIMS

Docosahexaenoic acid (DHA) is the most abundant omega-3 fatty acid in the brain and is accumulated by the fetal brain during the last trimester of pregnancy. Our objective was to determine whether high-dose DHA supplementation during the neonatal period, vs. placebo, improves behavioral functioning at 5 years in children born very preterm.

METHODS

This is a follow-up at 5 years corrected age of a subset of children who participated in a multicenter randomized controlled trial. The participants received a high-dose DHA supplementation, or a placebo, through maternal breastmilk until 36 weeks' postmenstrual age. Primary outcome was child behavioral functioning, assessed by the Total Difficulties Score from the Strengths and Difficulties Questionnaire (SDQ). Secondary outcomes included behavioral scores from the SDQ, executive functions assessment and global developmental performance. Neurodevelopmental outcomes were assessed through interviews with parents. Mean differences between DHA and placebo groups were estimated using mixed linear models. Subgroup analyses were conducted for sex and gestational age (GA) at birth.

RESULTS

Among 177 eligible children, 132 (74.6 %) completed neurodevelopmental assessment at 5 years (DHA, N = 64, placebo, N = 68). Total Difficulties Score did not differ between the DHA and placebo groups (mean differences, -0.9 [95 % confidence interval, -2.7 to 0.8], P = 0.30), nor any of the secondary outcomes. There was no significant interaction between treatment groups and sex, nor GA, for the primary outcome. However, significant interactions between treatment groups and sex or GA were found for some secondary outcomes.

CONCLUSIONS

In very preterm infants, high-dose DHA supplementation did not improve behavioral functioning at 5 years.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02371460, https://clinicaltrials.gov/study/NCT02371460.

Evidence on docosahexaenoic acid and arachidonic acid supplementation for preterm infants

PURPOSE OF REVIEW

For many decades, docosahexaenoic acid (DHA) supplementation was tested in premature infants to achieve an intake equivalent to the average level in breast milk, but this approach has led to conflicting results in terms of development and health outcomes. Higher doses of DHA closer to fetal accumulation may be needed.

RECENT FINDINGS

The efficacy of DHA supplementation for preterm infants at a dose equivalent to the estimated fetal accumulation rate is still under investigation, but this may be a promising approach, especially in conjunction with arachidonic acid supplementation. Current data suggest benefit for some outcomes, such as brain maturation, long-term cognitive function, and the prevention of retinopathy of prematurity. The possibility that supplementation with highly unsaturated oils increases the risk of neonatal morbidities should not be ruled out, but current meta-analyzes do not support a significant risk.

SUMMARY

The published literature supports a DHA intake in preterm infants that is closer to the fetal accumulation rate than the average breast milk content. Supplementation with DHA at this level in combination with arachidonic acid is currently being investigated and appears promising.

High-Dose Docosahexaenoic Acid in Newborns Born at Less Than 29 Weeks' Gestation and Behavior at Age 5 Years: Follow-Up of a Randomized Clinical Trial

Importance

Children born at less than 29 weeks' gestation are at risk of behavioral difficulties. This may be due in part to the lack of transplacental supply of docosahexaenoic acid (DHA), a key fatty acid with structural and functional roles in the brain.

Objective

To determine whether meeting the neonatal DHA requirement through supplementation is associated with improved behavioral functioning of children born at less than 29 weeks' gestation.

Design, Setting and Participants

This was a follow-up of children from 10 Australian participating centers in a multi-center, blinded, parallel group randomized clinical trial of infants born at less than 29 weeks' gestation conducted from June 2012 and September 2015, excluding those with additional fatty acid supplementation or major congenital or chromosomal abnormalities. Follow-up took place from August 2018 to May 2021. Parents of surviving children who had not withdrawn from the original trial were invited to complete questionnaires when the child turned 5 years' corrected age.

Interventions

Infants were randomized to receive daily enteral emulsions providing 60 mg/kg/d of DHA or a soy-oil emulsion (with no DHA) from within the first 3 days of enteral feeding until 36 weeks' postmenstrual age or discharge home, whichever occurred first.

Main Outcomes and Measures

The primary outcome of this follow-up was parent-rated behavior and emotional functioning as indicated by the Total Difficulties score of the Strengths and Difficulties Questionnaire. Parents also completed questionnaires about their child's behavioral manifestations of executive functioning, as well as a range of health outcomes to assess potential longer-term side effects of DHA intervention.

Results

Primary outcome data were available for 731 children (76% of 958 surviving eligible children; 361 in the intervention group and 370 in the control group). Of these 731, 452 (47%) were female, and the mean (SD) corrected age at follow-up was 5.4 (0.5) years. Following imputation for missing data, the mean Total Difficulties score was the same in both groups (intervention group, n = 465; mean [SD], 11.8 [6.3]; control group, n = 493; mean [SD], 11.8 [6.0]; mean difference adjusted for sex, gestational age stratum, and hospital, 0.01; 95% CI, -0.87 to 0.89; P = .98). There was no evidence for differences between the groups in any secondary outcomes of behavior, executive functioning, or health.

Conclusions and Relevance

In this follow-up of a randomized clinical trial, enteral DHA supplementation at the equivalent of the estimated in utero dose for infants born at less than 29 weeks' gestation did not improve behavioral functioning at age 5 years. There were no indications of adverse effects with DHA supplementation.

Trial Registration

Australian New Zealand Clinical Trial Registry: ACTRN12612000503820.