Western dietary pattern during pregnancy and early childhood increases risk of childhood asthma dependent on socioeconomic status

Abstract Background A Western dietary pattern (WDP) is linked to socioeconomic status (SES) and has been proposed as a risk factor for childhood asthma. However, how SES influences the relationship between dietary patterns and asthma risk remains poorly understood. Objective We aimed to investigate the interplay between SES and WDP during pregnancy and early childhood on risk of childhood asthma. Methods We analyzed 594 mother–child pairs from the COPSAC 2010 cohort. Maternal food frequency questionnaires (FFQs) were completed during pregnancy, and children were followed for asthma/wheeze until age 10 years. Untargeted plasma metabolomics profiles were obtained at pregnancy week 24 and child ages 6 and 18 months. A WDP score derived from FFQs was used to compute WDP metabolite scores using sparse partial least squares (sPLS). Associations between WDP and asthma/wheeze and their interactions with SES were evaluated by regression models. Replication was performed in 772 mother–child pairs from VDAART with comparable metabolomics data and in 388 children from COPSAC 2000 with neonatal dried blood spot metabolomics. SES was defined using principal component analysis of household income, maternal education, and maternal age. Results In COPSAC 2010 , SES was inversely correlated with WDP ( r = −0.40 to −0.14; p < .01). Significant WDP–SES interactions were observed for multiple asthma/wheeze outcomes ( p < .05). Among children with low SES, higher maternal WDP FFQ‐scores were associated with an increased risk of recurrent wheeze until 3 years (aHR = 1.29 [1.03–1.60], p = .023) and asthma until 10 years (aHR = 1.32 [1.06–1.65], p = .015) and higher child WDP metabolite‐score were associated with asthma until 10 years (aHR = 1.87 [1.21–2.90], p = .005). No significant WDP–SES interactions were observed in the replication cohorts; however, low SES was independently associated with asthma/wheeze in VDAART, and higher WDP‐scores were associated with increased risk in COPSAC 2000 among low‐SES children. Conclusions WDP during pregnancy and early childhood is associated with increased risk of childhood asthma/wheeze, with evidence supporting a directional association with SES rather than effect modification.