Sex Differences in Respiratory Physiology

There is substantial evidence for intrinsic sex differences in respiratory and pulmonary anatomy and physiology across the life span, indeed starting in utero and extending through aging. Such differences are likely modulated by gonadal hormones throughout life, further influenced by environmental and behavioral factors. Furthermore, intrinsic sex differences also modulate pathophysiology, incidence, morbidity, and mortality of several lung diseases including inflammatory and allergic diseases such as asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, cancers, and pulmonary vascular disease. In this introductory chapter, we establish the existence and portfolio of inherent sex differences in the structure and function of the respiratory system across the age spectrum, setting the stage in subsequent chapters to understand their potential role in disease pathways, along with the modulatory role of sex steroids and the environment. The importance of focusing on sex differences lies in the increasing incidence of lung diseases particularly in women and the need to address lung diseases across the life span from neonatal wheezing, asthma, and bronchopulmonary dysplasia through both obstructive and restrictive diseases in the elderly for example.