Prenatal polyunsaturated fatty acids and child asthma: Effect modification by maternal asthma and child sex.

Abstract

Findings on prenatal polyunsaturated fatty acid (PUFA) intake and child wheeze and asthma have been inconsistent. We sought to examine associations between prenatal PUFA status and child wheeze/asthma and modifying effects of maternal asthma/atopy, child sex, and maternal race. Analyses included 1019 mother-child dyads with omega-3 (n-3) and omega-3 (n-6) PUFAs measured in second-trimester plasma; n-6/n-3 ratios were calculated. Child wheeze/asthma outcomes ascertained at age 4 to 6 years included ever physician-diagnosed asthma, current wheeze (symptoms past 12 months), current asthma (diagnosis and medication and/or symptoms past 12 months), and current diagnosed asthma. Each PUFA indicator and outcome was analyzed in separate models using modified Poisson regression with interaction terms. In quartile (Q) analyses, higher n-6 PUFAs were associated with increased risk of ever (risk ratio [RR] high vs low [RR Q4 vs Q1], 1.70; 95% CI, 1.07-2.71) and current (RR Q4 vs Q1, 1.70; 95% CI, 1.07-2.71) diagnosed asthma, whereas n-3 PUFAs were associated with lower risk (RR Q4 vs Q1, 0.59; 95% CI, 0.33-1.03) of current diagnosed asthma (P_trend < .05 for all). Higher n-6 PUFAs were associated with a higher risk of all respiratory outcomes among children born to women with asthma (P_interaction < .05 for all outcomes). A significant 3-way interaction between child sex, maternal asthma, and n-6/n-3 PUFA indicated that male children born to women with asthma and a higher ratio had the highest risk across wheeze/asthma outcomes (P_interaction < .05). Associations between prenatal PUFA status and childhood wheeze/asthma were modified by maternal history of asthma and child sex.