Prenatal Exposure to Endocrine-Disrupting Chemicals and Asthma and Allergic Diseases

Endocrine-disrupting chemicals (EDCs) interfere with endogenous hormones and are present in many consumer products. In addition, they affect the development and functions of the immune system. The prenatal period is critical, because exposure to EDCs can induce irreversible changes in the immune system and increase susceptibility to asthma and allergies later in life. Nonpersistent EDCs are of most concern owing to their high annual production and potential toxicity. In this review, we summarize the literature on the effects of prenatal exposure to nonpersistent EDCs-phthalates and phenols-on asthma and allergic diseases, describe the underlying biological mechanisms, and make recommendations. Between 2011 and 2020, a total of 19 prospective studies were published. Most of these were focused on phthalates and bisphenol A and few on other bisphenols, parabens, triclosan, and benzophenone-3. Evidence remains insufficient owing to differences in chemical use between countries, sociodemographic characteristics of the study populations, misclassification of exposure due to the high within-subject variability, and heterogeneity in the definition of health outcomes. EDCs can alter airway cell differentiation and gut microbiota, shift the immune response towards TH2, alter expression of T regulatory cells and TH17, and weaken innate immunity. In order to better understand the burden of EDCs on the respiratory and immune systems, we require thoughtfully designed studies to assess exposure, appropriately characterize asthma and allergic phenotypes, and evaluate biological mechanisms and EDC mixtures.