A study by A.R. Bournot et al titled “ Association between serum 25-hydroxyvitamin D status and respiratory tract infections requiring hospital admission: unmatched case-control analysis of ethnic groups from the United Kingdom Biobank cohort ” published on 29 December 2025 shows that those with lower vitamin D levels have a higher risk of respiratory tract infections (RTIs). This is a case-control study using UK data: Of the 36,258 participants included in the analysis, 34%

Vitamin D in its role in supporting the immune system has been discussed in recent decades. Perhaps it has been more openly discussed in...