How does obesity increase the Covid-19 morbidity?

[Capn_Carl]

Is it only because obesity is associated with other Covid complications, like diabetes?

[DSeid]

https://science.sciencemag.org/content/369/6509/1280

The physical pathologies that render people with obesity vulnerable to severe COVID-19 begin with mechanics: Fat in the abdomen pushes up on the diaphragm, causing that large muscle, which lies below the chest cavity, to impinge on the lungs and restrict airflow. This reduced lung volume leads to collapse of airways in the lower lobes of the lungs, where more blood arrives for oxygenation than in the upper lobes. “If you are already starting [with] this mismatch, you are going to get worse faster” from COVID-19, Dixon says.

Other issues compound these mechanical problems. For starters, the blood of people with obesity has an increased tendency to clot—an especially grave risk during an infection that, when severe, independently peppers the small vessels of the lungs with clots ( Science , 5 June, p. 1039). In healthy people, “the endothelial cells that line the blood vessels are normally saying to the surrounding blood: ‘Don’t clot,’” says Beverley Hunt, a physician-scientist who’s an expert in blood clotting at Guy’s and St. Thomas’ hospitals in London. But “we think that signaling is being changed by COVID,” Hunt says, because the virus injures endothelial cells, which respond to the insult by activating the coagulation system.

Add obesity to the mix, and the clotting risk shoots up. In COVID-19 patients with obesity, Hunt says, “You’ve got such sticky blood, oh my—the stickiest blood I have ever seen in all my years of practice.”

Immunity also weakens in people with obesity, in part because fat cells infiltrate the organs where immune cells are produced and stored, such as the spleen, bone marrow, and thymus, says Catherine Andersen, a nutritional scientist at Fairfield University. “We are losing immune tissue in exchange for adipose tissue, making the immune system less effective in either protecting the body from pathogens or responding to a vaccine,” she says.

The problem is not only fewer immune cells, but less effective ones …

[Capn_Carl]

Excellent. Thank you.

[panache45]

Thanks so much from someone who’s borderline obese. You’ve given me additional motivation to get my weight down.

[Deeg]

Very interesting. I didn’t realize we had good explanations for the problems linked with obesity.

[DavidNRockies]

I think there’s also the inflammation/cytokine storm piece:

https://www.nature.com/articles/s41366-020-0597-4