The American Medical Association on Monday urged Americans to stop using electronic cigarettes of any sort until scientists have a better handle on the cause of 450 lung illnesses and at least five deaths related to the use of the products.

The association has called on doctors to inform patients about the dangers of e-cigarettes, including toxins and carcinogens.Doctors are also urged to report any suspected cases of lung illness associated with e-cigarette use to the health department.

The recommendation followed advice from the US Centres for Disease Control and Prevention on Friday for people to consider not using e-cigarette products while it investigates the cause of the spate of severe lung illnesses associated with vaping.

Many, but not all, of the cases have involved those who used the devices to vaporise oils containing tetrahydrocannabinol (THC), the psychoactive component of cannabis.

Disease Control officials said some laboratories have identified vitamin E acetate in product samples and are investigating that as a possible cause of the illnesses.

Public health experts have not found any evidence of infectious diseases and believe the lung illnesses are probably associated with a chemical exposure.

E-cigarettes are generally thought to be safer than traditional cigarettes, which kill up to half of all lifetime users, the World Health Organization says. But the long-term health effects of vaping are largely unknown. -Reuters