Severe vitamin D deficiency is linked to a higher risk of hospitalization for respiratory tract infections, according to new research led by the University of Surrey. The study found that individuals with severe vitamin D deficiency, defined as levels below 15 nmol/L, were 33 percent more likely to be admitted to hospital for conditions such as bronchitis and pneumonia compared to those with sufficient vitamin D levels (at least 75 nmol/L).
Researchers analyzed data from 36,258 participants in the UK Biobank, making this the largest study of its kind. The team included scientists from the University of Surrey, University of Reading, and University of Oxford. Their findings highlight that middle-aged and older adults are at increased risk for respiratory tract infections. Globally, lower respiratory tract infections are among the top causes of death for people aged 50-74 and rank even higher for those over 75.
Abi Bournot, BBSRC Food Biosystems PhD Research Fellow and lead author at the University of Surrey, said: "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. This research attaches hard data to support the theory. Despite its importance to our overall health, many people are deficient and do not meet the government's recommended intake of 10 micrograms of vitamin D per day.
"Supplementation of the vitamin, especially in the winter months when our exposure to sunlight is limited, is an effective way of increasing vitamin D and reducing the risk of serious respiratory tract infections. This is particularly important for older people who are at higher risk of death from such infections, and ethnic minority communities in the UK, who are at a higher risk of vitamin D deficiency."
The study also found that each increase of 10 nmol/L in vitamin D was associated with a four percent decrease in hospitalization rates due to respiratory tract infections.
Dr Andrea Darling, BBSRC-funded Postdoctoral Researcher at the University of Surrey and senior author on the study stated: "Respiratory tract infections are a major threat to public health globally. Not only can they make an individual feel very unwell in many cases, they can also lead to hospitalization which puts strain on an already stretched health service.
"Our findings of a significant association between increased vitamin D levels in our bodies and reduced hospital admission rates warrants further study, and points to the potential for vitamin D supplementation and consumption of vitamin D fortified foods to reduce the risk of hospitalization with respiratory infections in the future, and therefore mitigate pressures on the NHS."
The full study has been published in The American Journal of Clinical Nutrition.
