Holistic evaluation of the impact of pregnancy urban exposome on infant wheezing and chest infections: an outcome-wide approach

Background Few studies have considered the complex interplay of the urban exposome in association with multiple respiratory outcomes during infancy. Aim Utilizing an outcome-wide exposome approach, we aimed to assess associations of pregnancy urban exposome with offspring wheezing and chest infections at different time points within the first 18 months of life. Methods The analysis included data from 1032 mother–child pairs from the Barcelona Life Study Cohort (BiSC) (2018–2021). In total, 44 urban exposome factors were assessed during pregnancy, including air pollution, noise, temperature, humidity, green and blue spaces, and socioeconomic and lifestyle factors. Wheezing and chest infection were evaluated simultaneously at 2, 6, 12, and 18 months. We applied mixed-response sparse reduced-rank regression (MsRRR), with resampling procedures, adjusting for potential confounders. This many-to-many modelling approach identifies exposures concurrently associated with multiple interrelated outcomes. Results We found 13 exposures consistently associated with wheezing and chest infection across four time-points. Maternal education was the most consistent protective factor with odds ratios (OR) ranging from 0.65 to 0.81 for university and 0.88 to 0.96 for secondary education (vs. primary education) (all p < 0.05). Other important protective factors were size of nearest green space and maternal light-intensity physical activity. NO₂ (OR 1.02–1.08), outdoor temperature (OR 1.02–1.04), and noise annoyance (OR 1.01–1.03) were consistently associated with increased risk. Area-level socioeconomic status indicators showed inverse associations. Conclusion Pregnancy urban exposome may influence both wheezing and chest infections in infancy. Identifying key determinants through an outcome-wide exposome approach can inform targeted public health interventions towards more holistic urban planning strategies.