The cystic fibrosis gender gap: potential roles of estrogen

Cystic fibrosis (CF) is a complex, multi-system, autosomal recessive disease predominantly affecting Caucasians that leads to vigorous airway inflammation and chronic respiratory infection, commonly with Pseudomonas aeruginosa. A variety of factors significantly modify the progression and severity of CF lung disease and the timing of the resulting mortality. We summarize here data indicating that there is in CF a female disadvantage in survival and morbidity, called the "CF gender gap". Although controversy exists regarding the nature and relative importance of the various contributing mechanisms involved, gender affects the progression of CF disease with respect to lung infection, decline in pulmonary function and nutritional status. These interrelated factors in turn have a negative impact on survival. This review will emphasize the increasing evidence that suggest a role for the effects of gender, and particularly the female sex hormone estrogen, on infection, inflammation and transepithelial ion transport, all major determinants of CF lung disease. Future elucidation of the pathophysiology of hormonal aggravation of CF lung disease may pave the way for novel therapeutic interventions. This, combined with the magnitude of the gender gap in CF mortality, strongly suggests that further work in this field is well justified.