Epidemiological research advances on antibiotic exposure in early life and child health

Early life is a critical window period that determines the growth and development of children, but this delicate and complex period is highly susceptible to the disturbance of various exogenous chemicals, which in consequence may lead to short-term or long-term adverse health effects in human beings. The massive use of antibiotics has contributed to widespread exposure in early life, along with the potentially adverse effects on child health, and has caused great concern in public health. This review summarized recent epidemiological studies on the population with early-life antibiotic exposure and associated health outcomes such as growth and development, allergies, and psycho-behavioral problems in children, as well as potential biological mechanisms underlying these associations. Current findings suggested that antibiotic exposure early in life, including pregnancy and infancy, is strongly associated with childhood allergic diseases (e.g., atopic dermatitis and asthma), growth and development (e.g., obesity and birth length), and childhood psycho-behavioral problems (e.g., autism and anxiety). It also suggested that antibiotic exposure may affect individual health through gut microbiota, thyroid function, inflammation factors, mitochondrial function, and epigenetic mechanisms. In the future, more large prospective birth cohorts should be established to determine the levels of internal exposure to different types of antibiotics at multiple time points in early life and to explore their associations with child health outcomes, as well as to further validate relevant mechanisms, aiming to provide high-quality scientific evidence for research on child health associated with environmental exposure in early life.