Background Lipid mediators derived from omega-6 and omega-3 polyunsaturated fatty acids (PUFA) contribute to the regulation of inflammatory processes in the lung. Adolescence represents an important stage of lung growth, and modifying the availability of PUFA through diet might hold potential for improved lung function. However, effects may depend on individual differences in PUFA metabolism. We assessed the association of rich sources of dietary PUFA with lung function in adolescents, and evaluated the modifying role of 17 single nucleotide polymorphisms (SNP) in the FADS gene cluster involved in PUFA metabolism.

Methods 1931 participants of the 15-year follow-up of the GINIplus and LISA birth cohort studies, with data on dietary intake (food-frequency questionnaire), spirometry, and genotyped SNPs of the FADS cluster, were included. Cross-sectional associations of rich dietary sources of omega-6 (margarine) and omega-3 (oily fish) PUFA with lung function z-scores (FVC and FEV1), were assessed by linear regression, adjusting for covariates (sex, age, height, BMI, parental education, asthma, daily calories). Genotypes were coded following an additive model (minor allele count: 0/1/2). Interactions between dietary PUFA and each SNP were independently tested. Following a significant interaction, analyses were additionally stratified by the relevant SNP genotype. Correction for multiple testing was performed according to Nyholt.

Results Mean GLI z-scores of FVC and FEV1 were -0.51 and -0.54, respectively. Margarine and oily fish each represented <1% of daily caloric intake. No significant cross-sectional associations were observed between these sources of PUFA and lung function. Although a single nominal effect was found for the interaction between oily fish and rs174449, with respect to FVC (see figure 1 for the association of oily fish and FVC stratified by genotype), it was no longer significant after correction for multiple testing.