LONDON (AP) -- Patients who need new lungs are better off getting donated organs from smokers than none at all, even though they probably won't live as long as those who get a lung transplant from a nonsmoker, a new study says.

Researchers say patients will survive longer if they are willing to accept lungs from anyone, including smokers. In Britain, that's a key issue, for about 40 percent of donated lungs come from people who have previously smoked.

Yet in recent years, several cases of British patients dying after getting lungs from smokers have sparked calls for the policy to be overhauled.

Doctors behind the new study said changing the U.K. transplant system would be wrong and lead to a spike in the number of people dying while waiting for donated lungs.

"That could deny patients the opportunity to get help," said Dr. James Neuberger, associate medical director of the Queen Elizabeth Hospital in Birmingham and one of the study's authors.

Neuberger and colleagues analyzed information from the U.K. Transplant Registry and the Office of National Statistics on the survival rates of 2,181 adult British patients waiting for lung transplants between 1999 and 2010. About 2 in 5 of those transplants came from smokers.

They found that patients who got lungs from smokers were about 46 percent more likely to die within three years after getting the replacement lungs compared to patients who got the organs from non-smokers. But they had a 21 percent lower chance of dying versus people who were still on the waiting list. The research was published online Tuesday in the journal, Lancet.

In the U.S., doctors also use lungs from smokers, although Dr. Norman Edelman, the chief medical officer for the American Lung Association, didn't have any data on how often that happens. The U.S. and the U.K. have similar overall smoking rates of about 20 percent.

Some experts said it wasn't realistic to expect organ donor systems to refuse lungs from smokers because the demand is such that nearly every usable lung is transplanted. The key issues in lung transplants involve the size of the lung and the donor's blood type, which must match the recipients.

"There is rarely an 'ideal' organ available," He said most organs have defects based on factors like underlying disease or the age and circumstances of the donor's death.

"A smoker donor is really just one more factor to consider," he said in an email.

In the U.K., advocates have called for patients to be given more information about organ donors before accepting a transplant. In 2010, the family of a 28-year-old woman with cystic fibrosis lodged a complaint when she died a year after getting lungs from someone who had smoked for three decades. They said she had not been told and would have been horrified to get a smoker's lungs.

Neuberger said patients had the right to refuse lungs from smokers as long as they understood the implications.

"I'd rather take the lungs from a smoker than get no lungs at all," he said.

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