Table 5.
Observational studies reporting association between selenium and COVID-19.
| First Author, Year [Ref] | Country | Study Period | N of Subjects Involved | Study Population (Sex, Mean Age) | Selenium Plasma Levels | Follow Up |
|---|---|---|---|---|---|---|
| Zhou, 2022 [53] | China | 27 January–18 May 2020 | 16 | Distribution according to COVID-19 disease severity: mild group males n = 5, females n = 3 (mean age 42.5 ± 6.93 years); severe group males n = 4, females n = 4 (mean age 51.9 ± 16.7 years) | Mild about 125 µg/Kg, severe about 90 µg/Kg | No |
| Im, 2020 [54] | South Corea | February–June 2020 | 200 | Males n = 29, females n = 21; mean age 52.2 ± 20.7 | Median value Females 96.7 ng/mL (90.6–107.8); males 101.4 ng/mL (86.9–105.7); total 98.3 ng/mL (90.3–107.6) | Yes |
| Skalny, 2021 [55] | Russia, Norway, France, Greece | March–June 2020 | 194 | Distribution according to COVID-19 disease severity: mild n = 50 (mean age 50.47 ± 15.91), moderate n = 50 (mean age 54.22 ± 12.5), severe n = 50 (mean age 64.5 ± 15.49); control group n = 44 (mean age 55.67 ± 4.36); Gender distribution (males/females): control 7/16; mild 25/25; moderate 31/19; severe 25/25 | Control 0.102 ± 0.016 μg/mL, mild 0.093 ± 0.020 μg/mL moderate 0.090 ± 0.022 μg/mL, severe 0.087 ± 0.031 μg/mL | No |
| Pincemail, 2021 [56] | Belgium | May 2020 | 9 | Mean age 64 (53–71); males n = 8, females n = 1 | Reference Interval 73–110 µg/L, median (range) 74 µg/L (59–103) | Yes |
| Zeng, 2021 [57] | China | Not specified, submission date June 2020 | 138 | Males n = 79, females n = 59 (total mean age 61.5); distribution according to COVID-19 disease severity: non-severe males n = 38, females n = 32 (global mean age 60); severe males n = 38, females n = 32 (global mean age 65) | Median value: all patients 22.95 μg/L (14.44–36.08) non-severe 25.55 μg/L (19.04–37.64) severe 20.27 μg/L (13.53–35.34) | Yes |
| Al-Saleh, 2022 [58] | Saudi Arabia, Canada | 3 June–11 July 2020 | 155 | Distribution according to COVID-19 disease severity: asymptomatic n = 16, mild n = 49, moderate n = 68, severe n = 22 age range: 18–95 years mean age 50 years. Females n = 78, males n = 77. | Mean ± SD: asymptomatic 86.56 ± 18.95 μg/L, mild 78.36 ± 18.04 μg/L, moderate 87.51 ± 19.26 μg/L, severe 76.6 ± 23.54 μg/L. Total 82.97 ± 19.91 μg/L | No |
| Moghaddam, 2020 [59] | Germany | Not specified, submission date July 2020 | 33 | Females n = 19, males n = 14 (mean age 77 years). Death: females n = 4, males n = 2 (mean age 89 years); discharge: females n = 15, males n = 12 (mean age 69 years). Reference cohort of EPIC (European Prospective Investigation into Cancer and Nutrition) | Mean ± SD: all Samples 50.8 ± 15.7 µg/L, discharge 53.3 ± 16.2 µg/L, death 40.8 ± 8.1 µg/L | No |
| Heller, 2021 [60] | Germany | Not specified, submission date August 2020 | 35 | Females n = 19, males n = 14 (mean age 77 years). Death: females n = 4, males n = 2 (mean age 89 years); discharge: females n = 15, males n = 14 (mean age 70 years). Reference cohort of EPIC (European Prospective Investigation into Cancer and Nutrition) | No data | No |
| Hackler, 2021 [61] | Germany | Not specified, submission date April 2021 | 35 | Females n = 20, males n = 15 (mean age 77 years). Death: females n = 5, males n = 2 (mean age 89 years); discharge: females n = 15, males n = 13 (mean age 69 years). Reference cohort of EPIC (European Prospective Investigation into Cancer and Nutrition) | No data | No |
| Soto, 2022 [62] | Mexico | 20 August–20 September 2020 | 86 | COVID-19 patients n = 61; males n = 44, females n = 17 (global mean age 56 ± 13 years); distribution according to COVID-19 disease severity: moderate n = 34 (mean age 54 ± 12), (females n = 23, males n = 11); severe n = 27 (mean age 59 ± 14 years), (females n = 6, males n = 21) | No data | No |
| Erol, 2021 [63] | Turkey | 15 July–15 December 2020 | 141 | Control pregnant patients n = 70, COVID-19 pregnant patients n = 71 in different trimesters; I trimester: control patients n = 26 (mean age 26.34 ± 4.02 years), COVID-19 patients n = 24 (mean age 28.37 ± 4.70 years); II trimester: control patients n = 22 (mean 28.0 ± 6.27 years), COVID-19 patients n = 26 (mean age 29.76 ± 6.66 years); III trimester control patients n = 22 (mean age 26.3 ± 4.11 years), COVID-19 patients n = 21 (mean 28.95 ± 4.77 years). | No data | No |
| Majeed, 2021 [64] | India | Not specified, submission date September 2020 | 60 | Control patients n = 30 (males n = 14, females n = 16) (mean age 33.5 years); COVID-19 patients n = 30 (males n = 24, females n = 6) (mean age 40.5 years) | Mean ± SD: COVID patients 69.2 ± 8.7 ng/mL, controls 79.1 ± 10.9 ng/mL | No |
| Younesian, 2022 [65] | Iran | Not specified, submission date March 2021 | 100 | Control patients n = 50; COVID-19 patients n = 50 (n = 13 non-survivor group–mean age 72 years; n = 37 survivor group - mean age 49 years) | Mean ± SD: COVID-19 patients 77. 8 ± 13.9 μg/L, healthy control individuals 91.7 ± 16.7 μg/L, females COVID-19 patients 77.8 ± 16.7μg/L, healthy control individuals 95.8 ± 18.8 μg/L, males COVID-19 patients 77.8 ± 12 μg/L, healthy control individuals 88.4 ± 14.5 μg/L, survivor group 77.9 ± 14.3 μg/L, non-survivor group 77.2 ± 12.3 μg/L | No |
| Kirankaya, 2022 [66] | Turkey | December 2020–May 2021 | 195 | COVID-19 patients n = 146 (males n = 64, females n = 82; mean age 120 months). Control group n = 49 (males n = 26, females n = 23; mean age 70 months). COVID-19 hospitalized n = 38 (males n = 19, females n = 19; mean age 87 months); COVID-19 outpatients n = 108 (males n = 45, females n = 63; mean age 124 moths) | Mean ± SD: control group 66.5 + 11.4 μg/L, COVID-19 (+) outpatients 58.8 + 8.3 μg/L, COVID-19 (+) hospitalized 52.1 + 9.6 μg/L | No |
| Kocak, 2022 [67] | Turkey | Not specified, submission date July 2021 | 92 | COVID-19 patients n = 60 (males n = 32, females n = 28; mean age years 48.8 years); distribution according to COVID-19 disease severity: asymptomatic n = 4 (males N2=, females n = 2; mean age years 41.25 years); mild n = 15 (males n = 13, females n = 2; mean age 31.9 years); moderate n = 28 (males n = 13, females n = 15; mean age 54.21 years); severe n = 13 (males n = 4, females n = 9; mean age 58 years). Control group n = 32 (males n = 11, females n = 21; mean age years 45.5 years) | Se (ppb) control patients 255.23 ± 42.67 μg/kg, COVID-19 patients 215.34 ± 49.83 μg/kg; asymptomatic 236.17 ± 52.82 μg/kg, mild 196.85 ± 41.04 μg/kg, moderate 226.15 ± 48.79 μg/kg, severe 206.97 ± 57.18 μg/kg. | No |
| Ozdemir, 2022 [68] | Turkey | January–August 2021 | 15 | Moderate COVID-19 patients n = 15 (males n = 12, females n = 3; mean age 58.93 ± 6.70 years) | Before medical treatment 71.51 µg/L (65.08–86.69); after medical treatment 88.14 µg/L (79.08–109.85) | Yes |
| Du Laing, 2021 [69] | Belgium | Not specified, submission date August 2021 | 138 | COVID-19 patients n = 138 (study 1 on plasma: n = 79 patients; study 2 on serum: n = 59 | Mean value 56.6 µg/L; males 55, 57.6 µg/L, females 24, 54.2 µg/L, until 65 years 58.2 µg/L; above 65 years 53.9 µg/L, malignant neoplasm 50.2 µg/L, malignant neoplasm 66, 57.8 µg/L; diabetes 52.2 µg/L, diabetes 58.5 µg/L; obesity 52.2 µg/L, obesity 48 µg/L; chronic cardiac disease 57.0 µg/L | Yes |
| Skesters, 2022 [70] | Uk, Lettonia | Not specified, submission date November 2021 | 120 | 80 post-COVID-19 disease patients and 40 acutely ill patients. Other data non-specified | The extreme limits (min/max) were from 75.4 µg/L to 43.2 µg/L, acute disease 69.7 µg/L, no COVID Spring–summer wave 84.6 µg/L, no COVID Summer–autumn wave 88.2 µg/L | No |
| Chanihoon, 2022 [71] | Pakistan, UK, China | October 2021–January 2022 | 115 | COVID-19 patients n = 115 (non-smokers n = 63; smokers n = 52); control group n = 43 (non-smokers n = 19; smokers n = 24); 29–59 years. Distribution according to COVID-19 disease severity: non-smokers, mild n = 49, severe n = 12, critical=2; smokers, mild n = 52, severe n = 46, critical n = 2 | Referents non-smokers 232 ± 15.9 μg/L, smokers 209 ± 12.0 μg/L, COVID-19 patients non-smokers 125 ± 9.97 μg/L, smokers 102 ± 8.95 μg/L | No |