Global vitamin D deficiency <50nmol/L (20ng/ml) prevalence estimate: >50% based on published data for areas representing 2/3 of global population. Calcs: https://t.co/86j8LZAEw4 based on 3 papers linked in sheet. D<75nmol insufficiency has less data but global prevalence ~75-80%.

— Karl Pfleger (@KarlPfleger) May 7, 2021