Low Cholesterol Reduces Immune Function

A potential concern during the covid19 pandemic.

Low cholesterol, viral immunity, and risks associated with an earlier death.

These studies are not specific to the new coronavirus, but to other infectious respiratory viral diseases (and in all cause mortality).

Patients taking a cholesterol lowering statin had 38-67% lower titers for influenza which indicates an immunosuppressant effect on vaccine immune response.

This particular finding doesn’t necessarily apply to this new virus or in the infection versus a vaccine immune response, but it may. Further studies need to be done, but this is a new virus so they have not been done at this point.

Other studies mentioned in the article find greater flu hospitalizations in those on statins.

https://www.uspharmacist.com/article/the-impact-of-statin-therapy-on-influenzavaccine-response

While other studies demonstrate higher all cause mortality in older people (75 and older) with lower cholesterol versus those with higher cholesterol that weren’t taking cholesterol lowering medications.

“High cholesterol did not predict mortality in our (untreated) study population. On the contrary, low cholesterol levels were associated with higher mortality.”

This again raises potential concerns about having low cholesterol during this crisis in this case in the highest risk group of covid 19 complications, those 75 or older.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3442317/

The large 2001, Lancet Honolulu Heart study finds…

“Only the group with low cholesterol concentration at both examinations had a significant association with mortality.”

https://pubmed.ncbi.nlm.nih.gov/11502313/

A 2012, paper “Lipids and All-Cause Mortality among Older Adults: A 12-Year Follow-Up Study” finds…

“The mortality showed a positive association with low total cholesterol and a negative association with high total cholesterol. 

After the exclusion of underweight and premature mortality, there was a positive association only with total cholesterol <170 mg/dl. 

They showed higher mortality among older adults with low total cholesterol.”

https://www.hindawi.com/journals/tswj/2012/930139/#discussion

A 2016, paper in The British Medical Journal also finds “High LDL Cholesterol is inversely associated with mortality in most people over 60 years.”

The interesting reason why higher “bad” cholesterol in those 60 and above results in lower all cause deaths is largely lower infection and cancer related deaths. These appear to be immune related responses. 

https://bmjopen.bmj.com/content/6/6/e010401

Numerous papers have shown the benefits of higher versus low cholesterol in immune responses.

This might be important during this time. 

There is substantial evidence that low cholesterol increases risks of bad outcomes in general and specifically with infections. 

Every person of course is different. Individual risks and benefits should be thoroughly evaluated.

It’s a complex issue.