
Study Identifies Link Between Vitamin A Levels and Tuberculosis
The results of a new study suggest a link between vitamin A and tuberculosis.
Vitamin A has long been linked with eye and skin health. Now, the results of a new study suggest it may play an important role in tuberculosis (TB) risk as well.
Indeed, in a
“We initially were interested in vitamin D and drew and stored blood to evaluate [the link between it and TB], but [we] added vitamin A based on a previous study we had done suggesting that fruits and vegetables were protective against TB in kids,” senior author Megan Murray, DPH, MD, Ronda Stryker and William Johnston Professor of Global Health at Harvard Medical School told Contagion®. “We were really surprised to find the strong connection as it was very much unsuspected.”
In fact, the work of Dr. Murray et al is arguably the first modern study to identify a link between vitamin A and TB, which, according to World Health Organization (WHO)
For the more recent research, the team identified all (HIV-negative) household contacts for each case of confirmed pulmonary TB (the index patient). For those household contacts who tested positive for TB within 15 days of identification of the index patient in their respective cases, the authors randomly selected 4 controls for each household contact from among contacts who did not develop pulmonary TB, matching them according to gender and age. Among their sample, 192 of the 6751 household contacts developed secondary TB (with an additional 66 coprevalent cases), and the authors analyzed 180 of these cases against 709 matched controls.
After dividing the study subjects into quartiles based on levels of vitamin A in their blood samples, they found that the 76 household contacts with the lowest levels of vitamin A in their blood had 6 times the risk for TB compared to the 18 contacts with the highest levels. Further analysis revealed that vitamin A deficiency (with a univariate odds ratio of 7.65 and a multivariate odds ratio of 10.53) was a more significant risk factor for TB than even low socioeconomic status (1.69/1.61) and prior history of TB (2.89/2.11).
Based on their findings, the authors believe vitamin A deficiency has a potential role in identifying individuals at risk for TB, and that vitamin A supplementation may be an effective—and cost-effective—method for preventing new infections. On the latter point, Dr. Murray and her team are in the process of applying for a National Institutes of Health (NIH) grant to fund a study assessing the possible benefits of vitamin A supplementation in this setting.
“This is one of the strongest risk factors reported in a large epidemiological study in years,” Dr. Murray said in a
Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.
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