Obese people develop more infections than those of a healthy weight, shows new research. (Photo: Shutterstock)

Obese people more susceptible to infection

Obese people are more likely to suffer from throat or lung infections, shows new research.

If you carry extra weight, you may believe that this protects you from certain infections. But you’d be wrong.

Risk of infection increases if you are overweight. And the more weight you carry, the greater the risk, shows new research from The Danish Blood Donor Study.

Lead-author and medical student Kathrine Kaspersen from Aarhus University, Denmark, has studied data from more than 37,000 blood donors. The donors were carefully selected according to pre-supplied information on their health, weight, and height.

It is the first time that this association has been studied in healthy people.

"The project clearly shows that people who have a BMI over 30, contract more infections such as in the throat, pneumonia, abscesses, and other skin infections. The trend is clear: The higher the weight, the greater the risk," says Kaspersen.

Affects both men and women

Both men and women are susceptible, although with some differences.

"Generally there is a 50 per cent increased risk of infection in the severely obese. Abscesses affect both sexes, while there are more skin infections in men and more respiratory infections in women," says Kaspersen.

The most over-represented infection is in the form of abscesses.

The study shows that people with a BMI over 30 have 130 per cent increased risk of abscesses. Men had a 120 per cent greater risk of developing a skin infection, while women had 60 per cent greater risk of developing a respiratory infection, such as a throat infection or pneumonia.

But the study can only show that the risk of infection is high and not what the causes are.

"There are two immediate possibilities. It could be purely anatomical--that overweight people have more skin folds, which can cause infections, and that obesity might make it harder for people to breathe,” says Kaspersen.

“It may also be that obese people are simply not as resistant to infections," she says.

Colleague: not surprised by the results

Professor Bente Klarlund Pedersen, head of TrygFondens National Centre for Health at the University of Copenhagen hospital, Denmark, is not surprised by the results.

"It makes sense. Obese people have an immune system that is often plagued by inflammation,” says Pedersen.

“Research suggests that people who have chronic inflammation have a hard time fighting infections. It’s yet another example of a lifestyle of obesity and physical inactivity provides a fertile ground for poor health," he says.

Kaspersen believe that the results are troubling in light of an increasingly overweight population in her homeland, Denmark.

"It’s worth pondering that 13 per cent of Danes have a BMI over 30. Almost half of Danes are overweight and that number is steadily increasing,” she says.

“There are a lot of risks associated with being overweight, and this is just another sign that things are going in the wrong direction when it comes to obesity," says Kaspersen.


Read the Danish version of this story on Videnskab.dk

Translated by: Catherine Jex

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