Burning candles and fumes from cooking is harmful for people with mild asthma

A cosy set table, a nice steak in the pan, and romantic candlelight may sound like the start of a lovely evening. However, a new study from the Department of Public Health at Aarhus University suggests that you should be cautious about inhaling too much of the cosy atmosphere. Karin Rosenkilde Laursen, a postdoc at the department and co-author of the study, says:

"Our study shows that indoor air pollution caused by fumes from cooking and burning candles can lead to adverse health effects such as irritation and inflammation in young individuals with mild asthma. Among other things, we’ve found indications of DNA damage and signs of inflammation in the blood."

When we turn on the oven, place a pan on the hob, or light candles, ultrafine particles and gases are produced, which we then inhale. Previous studies have shown that these particles and gases can be detrimental to health. What sets this study apart is that the researchers have focused on the effects on young individuals with mild asthma, aged between 18 and 25, says Karin Rosenkilde Laursen:

"In the study, we observed that even very young individuals with mild asthma can experience discomfort and adverse effects if the room is not adequately ventilated during cooking or when burning candles. Young people are generally fitter and more resilient than older and middle-aged individuals. Therefore, it is concerning that we observed a significant impact from the particles on this particularly young age group."

But not only people diagnosed with asthma need to keep an eye on the indoor climate, she says.

"Even though the study focused on young asthmatics, its findings are interesting and relevant for all of us. Winter is approaching, a time when we tend to light many candles and perhaps are less likely to open doors and windows while cooking. By prioritising a healthier indoor climate, even when we're cosying up indoors, we may be able to help reduce the incidence of serious lung and cardiovascular diseases, as well as cancer."

Karin Rosenkilde Laursen plans to follow up this study with another examining how emissions from cooking and candles affect healthy adults.

The research results - more information 

• Studytype: The study is a randomised controlled double-blind exposure study in which 36 young asthmatics were exposed to three different exposures in the climate chambers at Aarhus University. They were exposed to emissions from cooking, emissions from burning candles and finally clean air. Each time, the participants were exposed for five hours under highly controlled conditions. During the exposures, we measured particles and gases, and participants reported symptoms related to irritation and general well-being. Biomarkers in relation to airway and systemic inflammatory changes were assessed before exposure, immediately after exposure and again the next morning.
• Partners: The Department of Chemistry, Aarhus University. The Department of Public Health, University of Copenhagen, The Department of Public Health and Community Medicine, University of Gothenburg, Aarhus University Hospital.
• Funding: The study is financed by Realdania Research grant of DKK 2.8 million. 
• Read more in the scientific article