Retinol Levels and Severity of Patients with COVID-19.

The new coronavirus infection represents a serious threat to global health and economies. In this sense, it is paramount to know the nutritional factors that may be related to the prognosis of the disease. Evidence shows that vitamin A may play an important preventive and therapeutic role in supporting respiratory infections as in COVID-19. The aim of our study was to evaluate the association of vitamin A (retinol) status with the prognosis of the disease. A case-control study from a cohort study was conducted in Brazil between May and October 2020. The study population was chosen by convenience, consisting of participants diagnosed with COVID-19. Recruitment was carried out using different approaches, including through dissemination on social media and in four hospitals in the city of Natal/RN, Brazil, recruiting participants from the COVID-19 ward and hospitalized participants who tested positive for the disease. The participants were allocated into two groups according to severity, with a group of mild (n = 88) or critical (n = 106) patients and compared to a control group (selected before the pandemic, n = 46). The extraction of retinol serum was performed and analyzed using the high-performance liquid chromatography method (HPLC). The retinol level was calculated in mmol/L, and levels below 0.7 µmol/L (20 µg/dL) were considered to be a vitamin A deficiency. Our findings suggest that the participants with mild and critical COVID-19 had lower retinol levels compared to the healthy controls (p = 0.03). In addition, milder cases of COVID-19 were associated with increased symptoms and prolonged symptoms after 90 days since the beginning of infection. However, the survival analysis showed no association with higher cases of death among participants with vitamin A deficiency (p = 0.509). More studies are needed to understand how nutritional status, including vitamin A levels, can influence prognosis and is a risk factor for the development of long COVID syndrome.

Previous vitamin D status and total cholesterol are associated with SARS-CoV-2 infection.

BACKGROUND: The relationship of vitamin D status and other biochemical parameters with the risk of SARS-CoV-2 infection remains inconclusive, especially in regions with high solar incidence. Therefore, we aimed to associate the 25-hydroxyvitamin D (25(OH)D) concentrations and lipid profile prior to the SARS-CoV-2 tests in a population from a sunny region in Brazil (5 degrees S, 35 degrees W). METHODS: This retrospective cohort study enrolled 1634 patients tested for SARS-CoV-2 of a private medical laboratory with 25(OH)D concentration and lipid profile measured ≥ 7 days before the date of the first SARS-CoV-2 RT-PCR test and were categorized according to 25(OH)D sufficiency (≥30 ng/mL) or insufficiency (<30 ng/mL). Multiple logistic regression analyses were performed to assess risk factors associated with positive tests for SARS-CoV-2. RESULTS: Average serum 25(OH)D was 33.6 ng/mL. Vitamin D deficiency (<20 ng/mL) was only found in 2.6% of the participants. Multivariate analysis demonstrated that patients > 49 y with insufficient 25(OH)D (<30 ng/mL) presented increased odds to test positive for SARS-CoV-2 (OR: 2.02, 95 %CI: 1.15 to 3.55, P = 0.015). The same is observed among those with total cholesterol > 190 mg/dL (OR: 1.90, 95 %CI: 1.10 to 3.28, P = 0.020). CONCLUSIONS: Previous insufficient 25(OH)D (<30 ng/mL) concentration and high total cholesterol were associated with SARS-CoV-2 infection among adults > 48 y in the study population. Further studies should be conducted to confirm whether measurement of 25(OH)D and lipid profile could be useful to identify patients who are more susceptible to COVID-19.