Vitamin D Deficiency and Insufficiency Among University Students: Prevalence, Risk Factors, and the Association Between Vitamin D Deficiency and Episodes of Respiratory Tract Infections.

Background: Vitamin D deficiency (VDD) and insufficiency (VDI) is a public health problem worldwide. Low blood levels of vitamin D have been associated with many illnesses, including respiratory tract infections (RTIs). This study aims to evaluate the prevalence of VDD and VDI among university students, assess the correlation with demographic and anthropometric factors, and determine the effect of VDD on the respiratory tract infection (RTI) incidence.