Sex-Based Differences in Asthma: Pathophysiology, Hormonal Influence, and Genetic Mechanisms

Asthma is a chronic inflammatory disease characterized by airway hyperresponsiveness, variable airflow obstruction, and persistent inflammation. While its pathophysiology is well established, growing evidence highlights significant sex-based differences in its prevalence, severity, and treatment response. Epidemiological studies indicate that asthma is more common in prepubertal boys but shifts toward a female predominance after puberty, with adult women experiencing higher morbidity and greater healthcare utilization. These disparities suggest a crucial role for sex hormones, genetic predisposition, and epigenetic regulation in asthma pathogenesis. Sex hormones modulate immune responses, contributing to disease progression. Estrogen enhances type 2 inflammation, increases eosinophilic infiltration, and upregulates IL-4 and IL-13 expression, leading to greater airway hyperreactivity in women. Additionally, progesterone fluctuations correlate with perimenstrual asthma exacerbations, while testosterone appears to exert a protective effect by dampening Th2-driven inflammation and airway remodeling. These hormonal influences contribute to sex-specific asthma phenotypes and treatment responses. Genetic and epigenetic factors further shape sex-related differences in asthma. The X chromosome harbors immune-regulatory genes, including TLR7 and TLR8, which amplify inflammatory responses in females. The sex-dependent expression of IL13 and ORMDL3 influences eosinophilic inflammation and airway remodeling. Epigenetic modifications, such as DNA methylation and microRNA regulation, further impact immune activation and corticosteroid responsiveness. For instance, Let-7 miRNAs modulate IL-13 expression, contributing to sex-specific inflammatory profiles. Environmental factors, including air pollution, obesity, and diet, interact with hormonal and genetic influences, exacerbating sex disparities in asthma severity. Obesity-related metabolic dysfunction promotes systemic inflammation, airway remodeling, and steroid resistance, disproportionately affecting women. Given these complex interactions, sex-specific approaches to asthma management are essential. Personalized treatment strategies targeting hormonal pathways, immune regulation, and metabolic health may improve outcomes for both men and women with asthma. Future research should focus on sex-based therapeutic interventions to optimize disease control and mitigate healthcare disparities.