Obesity and respiratory infections: does excess adiposity weigh down host defense?

Pulm Pharmacol Ther. 2013 Aug;26(4):412-9. doi: 10.1016/j.pupt.2012.04.006. Epub 2012 May 24.


The number of overweight and obese individuals has dramatically increased in the US and other developed nations during the past 30 years. While type II diabetes and cardiovascular disease are well recognized co-morbid conditions associated with obesity, recent reports have demonstrated a greater severity of illness in obese patients due to influenza during the 2009 H1N1 pandemic. Consistent with these reports, diet-induced obesity has been shown to impair anti-viral host defense in murine models of influenza infection. However, the impact of obesity on the risk of community-acquired and nosocomial pneumonia in human patients is not clear. Relatively few studies have evaluated the influence of diet-induced obesity in murine models of bacterial infections of the respiratory tract. Obese leptin deficient humans and leptin and leptin-receptor deficient mice exhibit greater susceptibility to respiratory infections suggesting a requirement for leptin in the pulmonary innate and adaptive immune response to infection. In contrast to these studies, we have observed that obese leptin receptor signaling mutant mice are resistant to pneumococcal pneumonia highlighting the complex interaction between leptin receptor signaling and immune function. Given the increased prevalence of obesity and poor responsiveness of obese individuals to vaccination against influenza, the development of novel immunization strategies for this population is warranted. Additional clinical and animal studies are needed to clarify the relationship between increased adiposity and susceptibility to community-acquired and nosocomial pneumonia.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adiposity*
  • Animals
  • Bacterial Infections / etiology
  • Bacterial Infections / microbiology
  • Bacterial Infections / physiopathology
  • Disease Models, Animal
  • Humans
  • Influenza, Human / etiology
  • Influenza, Human / physiopathology
  • Influenza, Human / virology
  • Leptin / metabolism
  • Mice
  • Obesity / complications*
  • Obesity / epidemiology
  • Obesity / physiopathology
  • Pneumonia / etiology
  • Pneumonia / microbiology
  • Pneumonia / physiopathology
  • Receptors, Leptin / metabolism
  • Respiratory Tract Infections / etiology
  • Respiratory Tract Infections / microbiology
  • Respiratory Tract Infections / physiopathology*
  • Severity of Illness Index
  • United States


  • Leptin
  • Receptors, Leptin