Background and Objective:

Omega-3 polyunsaturated fatty acids are important for brain development and cognition. Maternal supplementation during pregnancy has shown mixed impacts on child cognitive performance. This study assessed whether offspring FADS genotype modified the impact of prenatal DHA supplementation on cognitive scores at age 5 years.

Methods:

POSGRAD (Prenatal Omega-3 Supplementation and Child Growth And Development) was a double-blind randomized controlled trial conducted in Mexico, in which 1094 women were randomly assigned at 18-22 weeks gestation to receive 400 mg/day algal docosahexaenoic acid (DHA) or placebo through delivery. We included children born to mothers enrolled in the original trial who had genetic data and cognitive outcomes at age 5 years assessed using the McCarthy Scales of Child Abilities (MSCA) which includes subscales for verbal, perceptual, quantitative, memory, and motor abilities. Generalized linear models were used to assess interactions between FADS1 and FADS2 SNPs (rs175446, rs174602, rs1535, rs174448, rs174583) and DHA supplementation on child cognitive outcomes at age 5 years.

Results:

502 children (DHA= 254, placebo = 248) were included. Mean (SD) composite MSCA scores (sum of verbal, perceptual, quantitative) at age 5 years were 121.5 (22.5), and 121.0 (23.5) for the DHA and placebo groups, respectively. There were no significant differences by offspring FADs genotype (overall) on cognitive scores (all p > .05), neither was there evidence of effect modification of prenatal DHA supplementation (all p-interaction >.05).

Conclusions:

Variations in offspring FADS genotype appear not to influence child cognition at age 5 years and not to modify the impact of DHA on cognition.