Meta analysis using the most serious outcome reported shows 11% [-15‑47%] higher risk, without reaching statistical significance.
4 sufficiency studies analyze outcomes based on serum levels, showing 12% [2‑21%] lower risk for patients with higher vitamin B9 levels.
Results to date are contradictory. Several studies show higher mortality, however counfounding by indication may be significant — patients prescribed folic acid may have significantly higher risk on average. Studies independent of prescriptions based on patient condition show positive results Deschasaux-Tanguy, Farag, as do sufficiency studies. Folic acid may not be the most effective or safest form for supplementation Scaglione. Studies show that a significant fraction of people have genetic variations limiting the ability to convert folic acid to the active form.
All data to reproduce this paper and sources are in the appendix.
Covid Analysis et al., Apr 2024, preprint, 1 author.
