Decreased level of vitamin D in Post- COVID-19 patients compared to a control group

ABSTRACT

Before the COVID-19 pandemic started Vitamin D was discussed as a preventative strategy in acute respiratory tract infections. There is a growing evidence of beneficial effects of vitamin D supplementation in COVID-19 patients. The term post-COVID-19 syndrome (PCS) describes new, returning or ongoing symptoms more than 12 weeks after COVID-19 infection which cannot be explained by any other disorders or illnesses. The most common symptoms of PCS includes fatigue, difficulty breathing, memory/concentration/sleep problems persistent cough, muscle aches, depression, and others. We conducted a retrospective analysis of vitamin D level in a PCS cohort without hospitalisation. Taking of blood samples was part of the routine assessment in PCS consultation hours. We found significant lower vitamin D levels in the PCS cohort compared to a non-COVID control group. Within the non-COVID cohort there were no differences regarding vitamin D levels. Our results recorded for the first-time decreased vitamin D values in a PCS cohort compared to a control group. There are several potential reasons for these observations. The decrease could be the consequence of overcoming the infection by consumption of vitamin D. The reduction could also be the consequence of a longer duration of illness without exposure to sunlight or malnutrition. Similarly, reduced outdoor exercise during the pandemic with its restriction could have influenced vitamin D levels. Finally, reduced physical activity because of ongoing PCS symptoms like fatigue or exercise intolerance might be a possible explanation for the drop in vitamin D levels.