SYDNEY, Sept. 20 (Xinhua) -- An Australian-led study has shown that flavoured e-cigarettes, even those without nicotine, can change lung function in sufferers of respiratory diseases such as asthma.

Results of the study were published on Friday by researchers from Australia's University of Technology Sydney (UTS) along with colleagues from the University of Vermont in the USA and the Woolcock Institute of Medical Research, Australia.

Using mice as subjects, the study is the first to investigate the effects of flavoured e-cigarettes, with and without nicotine, on airways affected by allergic diseases.

Study lead author, David Chapman says the results contribute to growing evidence that flavour additives can become toxic when inhaled.

"The majority of e-cigarette smokers use flavoured liquids but there is some evidence that flavour additives can be toxic when inhaled," Chapman said.

"This is especially important for those with respiratory disease, whom are vulnerable to the effects of smoking."

Chapman says that the exact results on asthma affected lungs shown in their study was dependent upon the specific flavour -- meaning that not all e-cigarettes will have the same consequences for lung health.

In the study, Black Licorice flavour exaggerated airway inflammation the most, whereas Cinnacide had the opposite effect -- however Cinnacide increased airway sensitivity and Banana Pudding flavour exaggerated the level of tissue scarring.

All of the e-cigarettes with nicotine were shown to reduce inflammation in line with what was already known about the substance.

The researchers suggest that caution should be taken in promoting flavoured e-cigarettes to those with respiratory diseases, and that policymakers should consider restricting their use.