Long-term effect of high-dose supplementation with DHA on visual function at school age in children born at < 33 wk gestational age: Results from a follow-up of a randomized controlled trial

Background: Children born preterm are at risk of visual-processing impairments. Several lines of evidence have contributed to the rationale that docosahexaenoic acid (DHA) supplementation of preterm infants may improve outcomes in visual processing. Objective: The aim was to determine whether at 7 y of age children who were born very preterm and who received a high-DHA diet have better visual-processing outcomes than do infants fed a standard-DHA diet. Design: This was a follow-up study in a subgroup of children from a randomized controlled trial. Infants were randomly assigned to milk containing a higher concentration of DHA (1% of total fatty acids; high-DHA group) or a standard amount of DHA (0.2-0.3% of total fatty acids as DHA; control group). The randomization schedule was stratified by sex and birth weights of < 1250 or ≥1250 g. A total of 104 (49 in the high-DHA group and 55 in the standard-DHA group) children aged 7 y were assessed on a range of visual-processing measures, including visual acuity, contrast sensitivity, vernier acuity, binocular stereopsis, and visual perception. Results: There was no evidence of differences between the high-DHA and standard-DHA groups in any of the visual-processing measures. In the majority (12 of 13) of variables assessed, the direction of effect favored the control group. The study was large enough to detect a moderate treatment effect, if one truly existed. Conclusion: Supplementing human milk with DHA at a dose of w1% of total fatty acids given in the first months of life to very preterm infants does not appear to confer any long-term benefit for visual processing at school age.