Researchers at the Central Middlesex Hospital in London, led by Dr Vassiliki Bravis, examined the prevalence of vitamin D deficiency in an ethnically diverse population in London who had active tuberculosis. Out of 158 patients in the study, only 11 (7%) had adequate vitamin D levels. Additionally, patients’ vitamin D levels did not vary seasonally as expected, but remained constant throughout the year.

It is currently unclear whether these findings represent a contributory factor to TB infection, with people with low vitamin D levels being more likely to contract the disease, or whether tuberculosis infection makes the body process vitamin D in an abnormal way, leading to patients becoming deficient. More research is now needed to establish whether vitamin D could provide a new line of treatment or preventative medicine against tuberculosis.

Vitamin D is manufactured by the skin after exposure to UV rays from sunlight. If you live in the UK, your vitamin D levels should fluctuate seasonally with the amount of sunlight you are exposed to, being higher in the summer and lower in the winter. Approximately 14.5% of the UK population is vitamin D deficient. However, vitamin D deficiency is more common amongst the Asian and African population, in whom TB infection is also more prevalent. Previous work indicates that vitamin D may help ward off tuberculosis as it mediates a key immune response against the bacterium that causes TB. Tuberculosis is a major global health problem, which causes over 2 million deaths every year.

Researcher Dr Vassiliki Bravis said:

“Previous research has shown that high levels of vitamin D can help inhibit tuberculosis infection. Our work shows that, within a London population, the majority of TB patients we treat are vitamin D deficient. Currently, we don’t know whether this vitamin D deficiency is a contributing factor towards them developing the disease or whether tuberculosis infection makes the body process vitamin D in an abnormal way, meaning that sufferers subsequently become vitamin D deficient. Looking towards the future, we now need to carry out trials to establish whether vitamin D supplementation could be used effectively to either prevent or help treat tuberculosis infection.”