Undernutrition Linked to Increased Risk of Tuberculosis Disease
A new study has found that undernourished household contacts of individuals with tuberculosis (TB) are three times more likely to progress to TB disease. However, the study did not find that undernourished contacts were at increased risk of testing positive for TB infection as compared to well-nourished individuals. This suggests that undernutrition may not increase the risk of infection with the TB germ, but rather may impair the immune system’s ability to contain the infection.
The study, which was published in the journal Clinical Infectious Diseases, followed nearly 900 household contacts of persons who were newly diagnosed with TB. The contacts were screened to make sure they did not have TB disease at enrollment, and then followed for up to four years to see if they developed TB disease. Those who had a negative TB infection test at enrollment were retested to see if it had turned positive.
The researchers found that undernourished household contacts were three times more likely to progress to TB disease than well-nourished household contacts. However, they did not find that undernourished contacts were at increased risk of testing positive for TB infection as compared to well-nourished individuals.
This suggests that undernutrition may not increase the risk of infection with the TB germ, but rather may impair the immune system’s ability to contain the infection. This is an important finding, as it can help to guide how we can best protect undernourished individuals, who are a key and vulnerable population in the fight against TB.
“We now have greater insight into the mechanism by which undernutrition leads to greater TB risk,” said Dr. Pranay Sinha, MD, corresponding author on the study and assistant professor of medicine at Boston University Chobanian & Avedisian School of Medicine. “It is not by increasing infection, instead, it is by failing to contain the infection when it happens. Fortunately, undernutrition is a modifiable risk factor. Our findings should prompt TB programs to promptly provide adequate rations for the entire household to prevent TB disease among household contacts in addition to TB preventive therapy.”
The findings of this study have important clinical implications. They suggest that undernutrition is a risk factor for TB disease, and that undernourished individuals should be prioritized for TB preventive therapy. Additionally, the findings suggest that improving nutrition may be an important strategy for reducing the burden of TB.
