Table 2.

Studies assessing micronutrient supplementation on outcomes.

Author, Year [Ref.]	Reported Study Design; Country of Study	Population Source: Period of Data Collection	Population Size (% Men); Number of Subjects with ≥1 Comorbidity	Mean Age (SD)	Micronutrient in Question	Outcome Reported [I: Incidence of COVID-19 Episode; S, Severity of COVID-19 Episode]
Annweiler, 2020 [18]	Retrospective cohort; France	Nursing Home: Mar–Apr 2020	66 (22.7); 66	87.7 (9.0)	Vitamin D3 a	S: Death from COVID-19 episode
Capone, 2020 [46]	Retrospective cohort; United States	Hospital: till 20 Apr 2020 (start date unspecified)	102 (53.9); 61	63.22 (53.3–74.3) *	Vitamin C & zinc b	S: Death during course of follow-up (all-cause mortality) S: Progression to respiratory-related complication (defined by requiring invasive mechanical ventilation) due to COVID-19 episode
Castillo, 2020 [47]	Open-label, double blind randomised controlled trial; Spain	Hospital: Unspecified	76 (58.2); 26	53 (10)	Vitamin D3 c	S: Death during hospitalisation from COVID-19 episode S: ICU admission
Fasano, 2020 [48]	Retrospective, single-center case-control; Italy	Health registry: NR	1486 (56.9); 1486	Case: 70.5 (10.1) Controls: 73.0 (9.5)	Vitamin D b	I: Incidence of COVID-19 episode
Macaya, 2020 [29]	Retrospective cohort; Spain	Hospital: 5 Mar–31 Mar 2020	80 (43.8); 50	non-severe patients: 63 (50–72) * severe patients: 75 (66–84) *	Vitamin D b	S: Composite outcome for death, ICU admission and/or need for higher oxygen flow than that provided by a nasal cannula due to COVID-19 episode
Tan, 2020 [49]	Retrospective cohort; Singapore	Hospital: 15 Jan–15 Apr 2020	43 (60.4); 24	Non-supplemented: 64.1 (7.9) Supplemented: 58.4 (7)	Vitamin D, Magnesium & Vitamin B12 d	S: Death during hospitalisation from COVID-19 episode S: Composite outcome for progression to respiratory-related complication (defined by requiring oxygen therapy) or ICU admission due to COVID-19 episode S: Progression to respiratory-related complication (defined by requiring oxygen therapy)

NR, Not Reported. * median (interquartile range). ^a Oral supplementation of a 80,000 IU bolus dose in the week after/just before diagnosis, or in the previous month. ^b Supplementation status treated as a ordinal variable (Yes/No). ^c Oral Calcifediol in soft capsules (0.532 mg); Patients in the calcifediol treatment group continued with oral calcifediol (0.266 mg) on day 3 and 7, and then weekly until discharge or ICU admission. ^d Oral supplementation of 1000-IU dose of vitamin D3 (cholecalciferol), 150 mg of magnesium oxide, and 500 mg vitamin B12 (methylcobalamine) for ≤14 days daily, until patient subsequently deteriorated or was deemed to have recovered based on symptom resolution and two consecutive negative SARS CoV-2 reverse transcriptase PCR respiratory sample.