On February 21, Kenneth Warner, honorary dean of the School of Public Health of the University of Michigan and honorary professor of Avedis Donabedian, said that there was sufficient evidence to support the use of e-cigarettes as a first-line auxiliary means for adults to quit smoking.

"Too many adults who want to quit smoking can't do it," Warner said in a statement. "E-cigarettes are the first new tool to help them in decades. However, only a relatively small number of smokers and healthcare professionals are aware of their potential value."

In a study published in the journal Nature Medicine, Warner and his colleagues looked at e-cigarettes from a global perspective, and studied countries that advocated e-cigarettes as a way to quit smoking and countries that did not advocate e-cigarettes.

The authors said that although the United States and Canada recognized the potential benefits of using e-cigarettes, they believed that there was insufficient evidence to recommend e-cigarettes to quit smoking.

However, in the UK and New Zealand, the top support and promotion of e-cigarette as a first-line smoking cessation treatment option.

Warner said: We believe that governments, medical professional groups and individual health care professionals in the United States, Canada and Australia should give more consideration to the potential of e-cigarettes in promoting smoking cessation. E-cigarettes are not the solution to end the damage caused by smoking, but they can contribute to the realization of this noble public health goal.

Warner's previous research found a large amount of evidence that e-cigarettes are an effective smoking cessation tool for American adults. Every year, hundreds of thousands of people in the United States die from smoking-related diseases.

In addition to assessing the differences of regulatory activities in different countries, researchers also studied the evidence that e-cigarettes promote smoking cessation, the impact of e-cigarettes on health and the impact on clinical care.

They also cited the FDA's designation of some e-cigarette brands as suitable for protecting public health, which is the standard required to obtain marketing approval. The researchers said that this action indirectly implied that FDA believed that e-cigarettes could help some people who would not have done so to quit smoking.

Warner and colleagues concluded that the acceptance and promotion of e-cigarettes as a smoking cessation tool may depend on continuous efforts to reduce the exposure and use of e-cigarettes by young people who have never smoked. These two goals can and should coexist.