The abbreviation COPD stands for chronic obstructive pulmonary disease and the disease makes it difficult for patients to breathe. However, the disease affects other organs as well as the lungs. It is also linked to an increased risk of conditions such as diabetes, cancer and heart failure.

"Despite this, until now most focus has been on respiratory infections; infections in other organs have not been studied to the same extent," says Dr Malin Inghammar.

In her thesis, Dr Inghammar has shown that individuals in Sweden who have been diagnosed with COPD have a three times higher risk of active tuberculosis than the population in general. They are also at higher risk of invasive pneumococcal disease, a type of infection that can cause meningitis and septicaemia.

In another study, Malin Inghammar has looked at the presence of bacteria in the blood of COPD patients and control subjects from the general population. A wide range of bacteria, such as coliform bacteria and staphylococcusaureus, were seen to be 2.5 times more frequent in the blood of patients with COPD.

Tuberculosis is a rare disease in Sweden, so the association between COPD and TB is not of great importance in Sweden. However, the association could be important for countries such as India and China, where TB is still a common disease and where smoking is on the increase. Doctors may need to have increased awareness of dangerous infection-causing bacteria in any country.

"The next step is to study what causes the link. Does the cortisone treatment that is usually given to COPD patients make them vulnerable to infections? Or is the susceptibility to infection due to other factors, such as the weight loss, muscle weakness and anemia that are associated with the condition?" asks Malin Inghammar.

Her findings could in the future lead to changes in the treatment of COPD. If COPD patients are at extra high risk of hospital-acquired infections, then perhaps more care should be taken before admitting them to hospital, and greater reflection made on all the factors that could entail an increased risk of infection.