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

BACKGROUND: Findings on prenatal polyunsaturated fatty acid (PUFA) intake and child wheeze and asthma have been inconsistent.

OBJECTIVE: 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.

METHODS: 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.

RESULTS: 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 < .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 < .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 < .05).

CONCLUSIONS: Associations between prenatal PUFA status and childhood wheeze/asthma were modified by maternal history of asthma and child sex.