People living in homes with water damage, damp floors or visible mould are more likely to have chronic sinus problems and bronchitis, as well as allergies, asthma and other breathing disorders, according to a large study from Sweden.

About 11 percent of homes in the study had visible signs of dampness - and the more signs were present, the higher the likelihood that residents had nose, throat and lung-related health problems, according to the report in Clinical and Experimental Allergy.

“A lot of papers show an association between asthma-related symptoms and building dampness. What’s new is the association between chronic inflammation and building dampness,” said senior study author Christer Janson of Uppsala University.

“This is an important finding as chronic inflammation is quite a common condition with a very negative side effect on quality of life,” he told Reuters Health by email. “We were surprised that the association with building dampness was so strong.”

Non-smokers with any dampness signs were 90% more likely to have night-time shortness of breath

The researchers analysed data from more than 26,000 adults in four Swedish cities who responded to a questionnaire about respiratory symptoms, smoking, education and environmental exposures. In particular, the study team was interested in chronic rhinosinusitis (CRS).

They identified dampness by asking about visible water damage, floor dampness or visible mould seen in the home during the last 12 months and gave participants a dampness exposure score based on how many of these signs were present.

A total of 2,992 people, or 11.3%, reported any signs of dampness. For 8.3% of the study participants, one sign was present, for 2.3% there were two signs and for 0.7% all three signs were seen in the home.

Reported dampness was more common in humid or mild climates, as compared to areas of the country with longer, colder winters. People reporting damp homes were more likely to be women, unemployed or full-time students, smokers and less likely to be retired.

Compared to non-smokers with no signs of dampness at home, non-smokers with any dampness signs were 90% more likely to have night-time shortness of breath, 77% more likely to have chronic rhinosinusitis and 67% more likely to have chronic bronchitis. They also had higher rates of wheeze, nighttime coughing, asthma and allergies.

For chronic rhinosinusitis, the authors note, the degree of increased risk from dampness for nonsmokers was about the same as the effect of smoking for people without dampness in the home.

“I found it both interesting and alarming that the adverse effects were stronger among people with low socioeconomic status due to limited possibilities for moving to a better home or making needed renovations,” said Jouni Jaakkola of the University of Oulu in Finland, who wasn’t involved in the study.

Future studies should look at long-term results to better understand cause and effect with dampness at home, Jaakkola told Reuters Health by email.

“Cross-sectional studies (like this one) may underestimate the effects if people who get symptoms in damp homes change to better homes,” he said.