Interactions between a polygenic risk score for plasma docosahexaenoic fatty acid concentration, eating behaviour, and body composition in children

Background: The relationship between eating behaviour and current body weight has been described. However little is known about the effect of polyunsaturated fatty acids (PUFA) in this relationship. Genetic contribution to a certain condition is derived from a combination of small effects from many genetic variants, and polygenic risk scores (PRS) summarize these effects. A PRS based on a GWAS for plasma docosahexaenoic fatty acid (DHA) has been created, based on SNPs from 9 genes.

Objective: To analyze the interaction between the PRS for plasma DHA concentration, body composition and eating behaviour (using the Children Eating Behaviour Questionnaire) in childhood.

Subjects/methods: We analyzed a subsample of children from the Maternal, Adversity, Vulnerability and Neurodevelopment (MAVAN) cohort with PRS and measurements of eating behaviour performed at 4 years of age (n = 210), 6 y (n = 177), and body fat determined by bioelectric impedance at 4 y and 6 y or by air displacement plethysmography and dual-energy X-ray absorptiometry at 8 y (n = 42 and n = 37). PRS was based on the GWAS from Lemaitre et al. 2011 (p threshold = p < 5*10^-6), and a median split created low and high PRS groups (high PRS = higher DHA level).

Results: In ALSPAC children, we observed an association between PRS and plasma DHA concentration (β = 0.100, p < 0.01) and proportion (β = 0.107, p < 0.01). In MAVAN, there were interactions between PRS and body fat on pro-intake scores in childhood, in which low PRS and higher body fat were linked to altered behaviour. There were also interactions between PRS and pro-intake scores early in childhood on body fat later in childhood, suggesting that the genetic profile and eating behaviour influence the development of adiposity at later ages.

Conclusions: A lower PRS (lower plasma PUFA) can be a risk factor for developing higher body fat associated with non-adaptive eating behaviour in childhood; it is possible that the higher PRS (higher plasma PUFA) is a protective feature.