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

Abstract

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.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.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.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.Supplementing human milk with DHA at a dose of ∼1% 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. This trial was registered at anzctr.org/au as ACTRN12606000327583.