Effect modification of FADS2 polymorphisms on the association between breastfeeding and intelligence: results from a collaborative meta-analysis. (11th December 2018)

• Record Type: Journal Article
• Authors: Hartwig, Fernando Pires; Davies, Neil Martin; Horta, Bernardo Lessa; Ahluwalia, Tarunveer S; Bisgaard, Hans; Bønnelykke, Klaus; Caspi, Avshalom; Moffitt, Terrie E; Poulton, Richie; Sajjad, Ayesha; Tiemeier, Henning W; Dalmau-Bueno, Albert; Guxens, Mònica; Bustamante, Mariona; Santa-Marina, Loreto; Parker, Nadine; Paus, Tomáš; Pausova, Zdenka; Lauritzen, Lotte; Schnurr, Theresia M; Michaelsen, Kim F; Hansen, Torben; Oddy, Wendy; Pennell, Craig E; Warrington, Nicole M; Davey Smith, George; Victora, Cesar Gomes
• Is Part Of: International journal of epidemiology. Volume 48:Number 1(2019)
• Page Start: 45
• Page End: 57
• Publication Date: 2018-12-11
• Subjects: Breastfeeding -- intelligence -- FADS2 -- fatty acids -- effect modification -- meta-analysis; Epidemiology -- Periodicals; 614.4
• DOI: 10.1093/ije/dyy273
• Languages: English
• ISSNs: 0300-5771

Abstract

Abstract: Background: Accumulating evidence suggests that breastfeeding benefits children's intelligence, possibly due to long-chain polyunsaturated fatty acids (LC-PUFAs) present in breast milk. Under a nutritional adequacy hypothesis, an interaction between breastfeeding and genetic variants associated with endogenous LC-PUFAs synthesis might be expected. However, the literature on this topic is controversial. Methods: We investigated this gene × environment interaction through a collaborative effort. The primary analysis involved >12 000 individuals and used ever breastfeeding, FADS2 polymorphisms rs174575 and rs1535 coded assuming a recessive effect of the G allele, and intelligence quotient (IQ) in Z scores. Results: There was no strong evidence of interaction, with pooled covariate-adjusted interaction coefficients (i.e. difference between genetic groups of the difference in IQ Z scores comparing ever with never breastfed individuals) of 0.12[(95% confidence interval (CI): −0.19; 0.43] and 0.06 (95% CI: −0.16; 0.27) for the rs174575 and rs1535 variants, respectively. Secondary analyses corroborated these results. In studies with ≥5.85 and <5.85 months of breastfeeding duration, pooled estimates for the rs174575 variant were 0.50 (95% CI: −0.06; 1.06) and 0.14 (95% CI: −0.10; 0.38), respectively, and 0.27 (95% CI: −0.28; 0.82) and −0.01 (95% CI: −0.19; 0.16) for the rs1535 variant. Conclusions: Our findings did not support an interaction between ever breastfeeding and FADS2 polymorphisms. However, subgroup analysis suggested that breastfeeding may supply LC-PUFAs requirements for cognitive development if breastfeeding lasts for some (currently unknown) time. Future studies in large individual-level datasets would allow properly powered subgroup analyses and further improve our understanding on the breastfeeding × FADS2 interaction.