Genetic and environmental risk factors for asthma: towards prevention

Asthma is a common chronic airway disease affecting an estimated 260 million individuals of all ages worldwide, contributing to substantial morbidity, mortality, and economic burden. Asthma is heterogeneous in age at onset (childhood vs adult onset), clinical presentation, type of underlying airway inflammation (type 2 high vs type 2 low), prognosis, and treatment response. Asthma is caused by multiple genetic and environmental factors, and possibly their interaction, across the life course. Genetic studies have provided important insights into the pathogenesis, biology, and immunology of asthma, fostering drug discovery. The role of polygenic risk scores in aiding asthma diagnostics and delineating individuals at high risk of asthma development is becoming more evident. Four modifiable environmental, social, and lifestyle risk factors for asthma are responsible for nearly 30% of the global disability-adjusted life-years asthma burden: high BMI, occupational exposures, NO₂ (as a proxy for traffic-related air pollution), and smoking. These modifiable risk factors offer substantial opportunities for primary prevention of asthma, at the individual and societal level. National, regional, and global strategies aligned with the UN Sustainable Development Goals are urgently needed to attenuate the predicted increase in asthma cases by 2050.