Could Low Vitamin D Influence Long-COVID Risk?

Summary: New research suggests a link between low vitamin D levels and an increased risk of long COVID. The condition, which extends COVID-19 symptoms beyond 12 weeks, affects a significant percentage of previously hospitalized patients.

In this controlled study, researchers found lower vitamin D levels in patients with long COVID, particularly those experiencing ‘brain fog’ symptoms.

While further studies are required, this research paves the way for potential vitamin D supplementation to mitigate the risk of long COVID.

Key Facts:

1. New research indicates a potential link between low vitamin D levels and an increased risk of long COVID, a condition in which COVID-19 symptoms persist beyond 12 weeks.
2. This study involved a highly-controlled group of patients who were hospitalized for COVID-19 but did not require intensive care, and found that those with long COVID had lower vitamin D levels, especially among those experiencing ‘brain fog’ symptoms.
3. While the research suggests vitamin D deficiency could be a factor in long COVID, further studies are needed to confirm this link and to investigate whether vitamin D supplementation could help reduce the risk or severity of the condition.

Source: European Society of Endocrinology

Long COVID risk has been found to increase with low levels of vitamin D, according to research presented at the 25th European Congress of Endocrinology in Istanbul. The findings suggest that individuals should have their vitamin D levels checked after COVID-19.

Also known as post-COVID-19 syndrome, long COVID is a new condition in which the effects of COVID-19 last for more than 12 weeks after contracting the initial infection. Studies have shown that it affects 50-70% of patients previously hospitalized for COVID-19, yet very little is known about the condition.

One risk factor for worse outcomes for hospitalized COVID-19 patients, such as intubation and mechanical ventilation or death, is low vitamin D levels, but its role in long COVID has not been adequately investigated.

For this study, supported by Abiogen Pharma SpA, researchers from the Vita-Salute San Raffaele University and IRCCS San Raffaele Hospital in Milan examined 100 patients aged 51-70 years, with and without long COVID.

They measured their vitamin D levels when first admitted to hospital for COVID-19 and six months after being discharged, and found lower vitamin D levels in patients with long COVID compared to those without.

This result was more evident in patients who experienced ‘brain fog’ symptoms, such as confusion, forgetfulness and poor concentration, at the six-month follow-up.

The researchers included patients without any bone conditions and only those who went to hospital for COVID-19, without ending up in the intensive care units (ICUs). They matched the two groups, with and without long COVID, in terms of age, sex, pre-existing chronic diseases and COVID-19 severity.

“Previous studies on the role of vitamin D in long COVID were not conclusive mainly due to many confounding factors,” said lead investigator Professor Andrea Giustina.

“The highly-controlled nature of our study helps us better understand the role of vitamin D deficiency in long COVID, and establish that there is likely a link between vitamin D deficiency and long COVID.”

While Professor Giustina acknowledges that larger studies are needed to confirm this link, he and his team are now focused on finding out whether vitamin D supplements can reduce the risk of long COVID.

“Our study shows that COVID-19 patients with low vitamin D levels are more likely to develop long COVID but it is not yet known whether vitamin D supplements could improve the symptoms or reduce this risk altogether.”

About this Long-COVID research news

Author: Joanna Williams
Source: European Society of Endocrinology
Contact: Joanna Williams – European Society of Endocrinology
Image: The image is credited to Neuroscience News

Original Research: Open access.
“Low Vitamin D Levels Are Associated With Long COVID Syndrome in COVID-19 Survivors ” by Andrea Giustina et al. Journal of Clinical Endocrinology & Metabolism

Abstract

Low Vitamin D Levels Are Associated With Long COVID Syndrome in COVID-19 Survivors 

Context

Long COVID is an emerging syndrome affecting 50% to 70% of COVID-19 survivors that still lacks predicting factors.

Objective

Due to the extraskeletal effects of vitamin D, we retrospectively assessed the association between 25(OH) vitamin D levels and long COVID in COVID-19 survivors 6 months after hospitalization.

Methods

Long COVID was defined according to NICE guidelines. Fifty long COVID and 50 non–long-COVID subjects matched on a 1:1 basis were enrolled from an outpatient clinic post-COVID cohort seen from August to November 2020. Therapies/comorbidities affecting calcium/vitamin D/bone metabolism, and/or admission to the intensive care unit during hospitalization were exclusion criteria. 25(OH) Vitamin D was measured at hospital admission and 6 months after discharge.

Results

We observed lower 25(OH) vitamin D levels, evaluated at follow-up, in subjects with long COVID than those without (20.1 vs 23.2 ng/mL, P = .03). Regarding the affected health areas evaluated in the entire cohort, we observed lower 25(OH) vitamin D levels in those with neurocognitive symptoms at follow-up (n = 7) than those without (n = 93) (14.6 vs 20.6 ng/mL, P = .042). In patients presenting vitamin D deficiency (<20 ng/mL), both at admission and at follow-up (n = 42), those affected by long COVID (n = 22) presented lower 25(OH) vitamin D levels at follow-up than those not affected (n = 20) (12.7 vs 15.2 ng/mL, P = .041). In multiple regression analyses, lower 25(OH) vitamin D levels at follow-up were the only variable significantly associated with long COVID in our cohort (P = .008, OR 1.09, CI 1.01-1.16).

Conclusion

COVID-19 survivors with long COVID have lower 25(OH) vitamin D levels than matched patients without long COVID. Our data suggest that vitamin D levels should be evaluated in COVID-19 patients after hospital discharge. The role of vitamin D supplementation as a preventive strategy of COVID-19 sequelae should be tested in randomized controlled trials.