Impact of vitamin D supplementation on COVID-19 mortality: A systematic review and meta-analysis

Doustmohammadian et al., Nutrition Clinique et Métabolisme, doi:10.1016/j.nupar.2025.12.001, Dec 2026
Mortality 33% improvement lower risk ← → higher risk Vitamin D  Doustmohammadian et al.  META ANALYSIS c19early.org Doustmohammadian et al., Nutrition Cli.., Dec 2026 0 0.5 1 1.5 2+ RR
Vitamin D for COVID-19
8th treatment shown to reduce risk in October 2020, now with p < 0.00000000001 from 136 studies, recognized in 18 countries.
No treatment is 100% effective. Protocols combine treatments.
6,300+ studies for 210+ treatments. c19early.org
Systematic review and meta analysis of 24 studies showing significantly lower COVID-19 mortality with vitamin D treatment.
20 meta analyses show significant improvements with vitamin D treatment for mortality1-14, mechanical ventilation1,5,6,11,15-17, ICU admission1,3,5,6,9,11,13,15-19, hospitalization11, severity2,4,5,10,20, and cases7,19,20.
Currently there are 136 vitamin D treatment for COVID-19 studies, showing 39% lower mortality [31‑45%], 17% lower ventilation [-5‑35%], 45% lower ICU admission [28‑57%], 22% lower hospitalization [13‑30%], and 17% fewer cases [9‑25%].
risk of death, 33.0% lower, OR 0.67, p = 0.04, RR approximated with OR.
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
Doustmohammadian et al., 26 Dec 2026, peer-reviewed, 6 authors.
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