People who are gluten intolerant run four times the risk of developing active tuberculosis (TB) infection, suggests research published in the journal Thorax. Gluten intolerance, or celiac disease, is a chronic inflammatory condition of the small bowel, caused by an exaggerated immune response to the gluten found in wheat, barley, and rye. It affects up to 1 percent of the population, and has been linked to several autoimmune diseases, as well as an increased likelihood of lymph gland cancer and complications of pregnancy.
The researchers analyzed Swedish hospital discharge records from 1964 to 2003, looking for diagnoses of celiac disease and TB. During this period, more than 15,500 people were diagnosed with celiac disease, almost a third of whom had been diagnosed as adults. The final analysis was based on 14,335 people, who were compared with almost 70,000 other people, who were free of the disease.
A prior diagnosis of celiac disease almost quadrupled the chances of active TB infection in both sexes, overall, while a diagnosis in childhood tripled the chances.
In a separate analysis, the researchers looked at the risk of subsequently developing celiac disease after a diagnosis of TB in the same group of people. This showed that a prior diagnosis of TB more than doubled the risks of celiac disease.
The link between TB and gluten intolerance was not influenced by levels of poverty or deprivation with which TB is normally associated.
Poor intake of vitamin D and calcium in people with gluten intolerance as a result of both intestinal mal-absorption and the nutritional deficiencies of a gluten free diet, may help to explain the findings, suggest the authors. Vitamin D is a key player in marshalling the immune response against TB infection.
Reference: Celiac disease and risk of tuberculosis: a population based cohort study. Online First Thorax. 2006.
Source: British Medical Journal