Early-life exposure to phthalates and bisphenols may increase the risk of asthma, wheezing, and rhinitis in children under five, according to a new pooled analysis of over 5,000 participants.
Researchers assessed the impact of prenatal and early childhood exposure to phthalates and bisphenols, chemical additives commonly found in plastics, on allergic conditions including asthma, wheeze, eczema, and rhinitis. The study combined data from four birth cohorts in Australia, Canada, and the United States, analyzing urinary biomarkers of these chemicals collected during pregnancy and early life.
Findings revealed a statistically significant association between prenatal exposure to dibutyl phthalates (DBP) and benzyl butyl phthalate (BBzP) and an increased risk of childhood asthma. Specifically, a two-fold increase in maternal urinary DBP and BBzP was linked to an 8% and 6% higher asthma risk, respectively. Additionally, prenatal levels of mono-(3-carboxypropyl) phthalate (MCPP) were associated with increased rhinitis in early childhood.
Postnatal exposure was also found to elevate the risk of wheezing. Children with higher postnatal levels of BBzP, di(2-ethylhexyl) phthalate (DEHP), and MCPP had a 5–9% increased risk of wheezing. Interestingly, these same chemicals showed an inverse association with eczema, suggesting a possible divergent effect on different allergic pathways.
Researchers also analyzed the effects of combined chemical exposures using a mixture model. A one-quartile increase in the postnatal chemical mixture was associated with a 14% increased risk of wheezing. Despite previous concerns, the study found minimal evidence that sex modified the associations.
These findings reinforce growing concerns about ubiquitous chemical exposure during critical developmental windows. The study highlights the need for clinicians to consider environmental risk factors when addressing early childhood allergic conditions and underscores the importance of ongoing public health efforts to reduce prenatal and early-life exposure to potentially harmful plastic additives.
Reference:
Boissiere-O’Neill T et al. Phthalates and bisphenols early-life exposure, and childhood allergic conditions: a pooled analysis of cohort studies. J Expo Sci Environ Epidemiol. 2025. https://doi.org/10.1038/s41370-025-00790-2.
