TY - JOUR
T1 - Effect modification of FADS2 polymorphisms on the association between breastfeeding and intelligence
T2 - Protocol for a collaborative meta-analysis
AU - Hartwig, Fernando Pires
AU - Davies, Neil Martin
AU - Horta, Bernardo Lessa
AU - Victora, Cesar Gomes
AU - Smith, George Davey
PY - 2016/6/1
Y1 - 2016/6/1
N2 - Introduction: Evidence from observational studies and randomised controlled trials suggests that breastfeeding is positively associated with IQ, possibly because breast milk is a source of long-chain polyunsaturated fatty acids. Different studies have detected gene-breastfeeding interactions involving FADS2 variants and intelligence. However, findings are inconsistent regarding the direction of such effect modification. Methods/design: To clarify how FADS2 and breastfeeding interact in their association with IQ, we are conducting a consortium-based meta-analysis of independent studies. Results produced by each individual study using standardised analysis scripts and harmonised data will be used. Inclusion criteria: breastfeeding, IQ and either rs174575 or rs1535 polymorphisms available; and being of European ancestry. Exclusion criteria: twin studies; only poorly imputed genetic data available; or unavailability of proper ethics approval. Studies will be invited based on being known to have at least some of the required data, or suggested by participating studies as potentially eligible. This inclusive approach will favour achieving a larger sample size and be less prone to publication bias. Discussion: Improving current understanding of FADS2-breastfeeding interaction may provide important biological insights regarding the importance of longchain polyunsaturated fatty acids for the breastfeeding- IQ association. This meta-analysis will help to improve such knowledge by replicating earlier studies, conducting additional analysis and evaluating different sources of heterogeneity. Publishing this protocol will minimise the possibility of bias due to post hoc changes to the analysis protocol.
AB - Introduction: Evidence from observational studies and randomised controlled trials suggests that breastfeeding is positively associated with IQ, possibly because breast milk is a source of long-chain polyunsaturated fatty acids. Different studies have detected gene-breastfeeding interactions involving FADS2 variants and intelligence. However, findings are inconsistent regarding the direction of such effect modification. Methods/design: To clarify how FADS2 and breastfeeding interact in their association with IQ, we are conducting a consortium-based meta-analysis of independent studies. Results produced by each individual study using standardised analysis scripts and harmonised data will be used. Inclusion criteria: breastfeeding, IQ and either rs174575 or rs1535 polymorphisms available; and being of European ancestry. Exclusion criteria: twin studies; only poorly imputed genetic data available; or unavailability of proper ethics approval. Studies will be invited based on being known to have at least some of the required data, or suggested by participating studies as potentially eligible. This inclusive approach will favour achieving a larger sample size and be less prone to publication bias. Discussion: Improving current understanding of FADS2-breastfeeding interaction may provide important biological insights regarding the importance of longchain polyunsaturated fatty acids for the breastfeeding- IQ association. This meta-analysis will help to improve such knowledge by replicating earlier studies, conducting additional analysis and evaluating different sources of heterogeneity. Publishing this protocol will minimise the possibility of bias due to post hoc changes to the analysis protocol.
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U2 - 10.1136/bmjopen-2015-010067
DO - 10.1136/bmjopen-2015-010067
M3 - Article
AN - SCOPUS:84975467172
SN - 2044-6055
VL - 6
JO - BMJ Open
JF - BMJ Open
IS - 6
M1 - A87
ER -