Swedish researchers are suggesting that people with celiac disease, also known as gluten intolerance, have an increased risk of developing tuberculosis (TB).
The risk for celiacs developing an active tuberculosis infection they say is four times more likely than in other people.
The new research by scientists at Orebro University Hospital in Sweden compared 14,335 people with gluten intolerance to 70,000 people without the condition.
People with celiac disease have an exaggerated immune response to the protein gluten found in wheat, barley and rye as it causes chronic inflammation of the small bowel.
Gluten intolerance affects about one percent of the population and has been linked to several autoimmune diseases, as well as with pregnancy complications and increased risk of lymph gland cancer.
The illness has a variety of symptoms including weight loss, diarrhea, fatigue, muscle cramps and abdominal pain and bloating.
The only treatment is to eat a gluten-free diet.
Dr. Jonas Ludvigsson and his team found that people diagnosed with celiac disease in adulthood had nearly four times the risk of active TB infection, while those diagnosed as children had triple the risk.
The research team also found that a prior diagnosis of TB nearly doubled the risk of celiac disease.
The researchers suggest the association between gluten intolerance and TB may be due to poor intake of vitamin D and calcium, caused by intestinal malabsorption and the nutritional deficiencies of a gluten-free diet, in people with celiac disease.
Vitamin D plays an important role in immune system response against TB infection.
Tuberculosis is a respiratory disease that is transmitted by an infected person coughing and sneezing in confined spaces.
It can be treated with antibiotics but drug-resistant strains have developed recently.
The illness kills about 1.7 million people around the world each year.
The study is published in the journal Thorax.