How does obesity affect the susceptibility of a patient to respiratory viral infections like COVID-19?

Bottom Line:

This review article explores how obesity affects immune function and the specific mechanisms involved. Obesity is associated with high levels of leptin, a hormone produced by fat cells that regulates appetite.

Reference:

Rebello, C. et al. Obesity, the most common comorbidity in SARS-CoV-2: is leptin the link? International Journal of Obesity (2020). https://doi.org/10.1038/s41366-020-0640-5

Date Published:

9 July 2020

Synopsis:

Previous literature shows that patients that suffer from obesity have increased disease severity when infected with COVID-19. In six university ICUs across New York, a significant inverse relationship between BMI and age were found in patients positive for COVID-19. While older patients were at an increased risk for detrimental infectious outcomes, younger patients that suffer from obesity were more likely to experience severe forms of the infection. This review article explores how obesity affects immune function and the specific mechanisms involved. Obesity is associated with high levels of leptin, a hormone produced by fat cells that regulates appetite. Leptin is also found to modulate T-cell number and function. Moreover, high levels of leptin results in activation of a protein called SOCS3 (suppressor of cytokine signaling 3) which decreases the responsiveness of regulatory T-cells, which are responsible for controlling the immune response. By disrupting T-cell function, the immune response is reduced resulting in greater susceptibility to respiratory viral infections.

Summary by: Eugenia Yeung