Lower 25(OH)D Linked to Higher Risk for Respiratory Tract Infection Hospitalization

THURSDAY, Jan. 29, 2026 (HealthDay News) — Low serum 25-hydroxyvitamin D (25[OH]D) is associated with an increased risk for respiratory tract infection (RTI) hospitalization, according to a study published in the February issue of the American Journal of Clinical Nutrition.

Abigail R. Bournot, from the University of Surrey in the United Kingdom, and colleagues examined the association between serum 25(OH)D status and hospitalization for RTIs among U.K. adults in an unmatched case-control study. A total of 36,258 adults were included in the analysis: 34, 28, 19, 11, and 7 percent were White, Asian, Black, other, and mixed ethnicity, respectively.

The researchers found that the RTI rate was 8.5 percent, and there was a significant association for higher serum 25(OH)D with a lower hazard ratio for RTI hospitalization (hazard ratio, 0.96 for each +10 nmol/L increase). Those with <15 nmol/L had a higher risk for RTI hospitalization compared with those with ≥75 nmol/L (reference) when stratifying for serum 25(OH)D (hazard ratio, 1.33). For 15 to 24, 25 to 49, and 50 to 74 nmol/L, the associations were not statistically significant. The interaction term of 25(OH)D-by-ethnicity was not statistically significant.

“Vitamin D is vital to our physical wellbeing. Not only does it keep our bones and muscles healthy, its antibacterial and antiviral properties are also thought to help reduce the risk of respiratory tract infections that can lead to hospitalization,” Bournot said in a statement. “This research attaches hard data to support the theory.”

One author disclosed ties to the biopharmaceutical industry.

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