Beyond BMI

The worldwide prevalence of obesity has increased rapidly in the last 3 decades, and this increase has led to important changes in the pathogenesis and clinical presentation of many common diseases. This review article examines the relationship between obesity and lung disease, highlighting some of the major findings that have advanced our understanding of the mechanisms contributing to this relationship. Changes in pulmonary function related to fat mass are important, but obesity is much more than simply a state of mass loading, and BMI is only a very indirect measure of metabolic health. The obese state is associated with changes in the gut microbiome, cellular metabolism, lipid handling, immune function, insulin resistance, and circulating factors produced by adipose tissue. Together, these factors can fundamentally alter the pathogenesis and pathophysiology of lung health and disease.