Genetic and environmental risk factors of asthma: a narrative review.

Asthma is a heterogeneous and polygenic disease, with numerous genes involved in immune regulation and respiratory epithelial function. However, currently identified genetic variants explain only part of asthma heritability. Environmental factors including smoking, stress, obesity, diet, occupational exposure, respiratory viral infections, early-life allergen exposure, low physical activity and air pollution (PM2.5) play an important role in disease development. The literature results also suggest that exposure to PM2.5 may increase the risk of asthma, particularly in genetically susceptible individuals. The aim of this narrative review was to provide an overview of environmental and genetic factors associated with asthma and to analyze the role of genetic risk variants and fine particulate matter (PM2.5) in the development of the disease. This review summarizes the current evidence on genetic and environmental factors involved in both the development of bronchial asthma and the determination of its severity, with an emphasis on their interaction.