For recipients of an organ transplant, smoking is even more dangerous than for the rest of the population, a recent analysis shows.

The review of studies on solid organ transplant patients found that more than 10 percent resume smoking after the operation. These smokers have more than 2.5 times the risk of nonskin cancers compared to transplant recipients who don't smoke, and elevated risks of new heart disease as well as death.

Transplant patients must remain on immunosuppressive medication for life to keep their bodies from rejecting the organ, which is why they already have an increased risk of cancer, infections and heart disease, researchers write in the journal Transplantation.

"In transplantation, smoking clearly has a negative impact, an even bigger impact than if you are a nontransplant person," said coauthor Sabina De Geest of the University of Basel in Switzerland.

The researchers reviewed 73 studies of transplantation, most focusing on kidney, heart or lung transplants, and they analyzed data on six potential risk factors before surgery and four outcomes after surgery.

Men were 30 percent more likely to smoke after a transplant than women, and younger, thinner people were also more likely to smoke than others.

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Those who continued or resumed smoking after a transplant were 40 percent more likely than others to develop new heart disease, 2.58 times more likely to develop a malignancy other than skin cancer and 1.74 times more likely to die during the follow-up period.

International consensus guidelines say that active tobacco smoking or smoking within the previous six months should be a disqualifying factor for a patient who needs a heart or lung transplant, and strongly recommend quitting before a kidney or liver transplant.

"Most transplant programs are really targeted to providing patients this information, before you have a transplant you go through an evaluation program," De Geest told Reuters Health.

But assessing smoking status and other health risk factors should be an ongoing process, she said, before, during and after transplantation, as long as 10 to 15 years after the transplant happens. Staying active and eating healthy are also important after a transplant, she said.

"It's a non-sexy part of transplantation, but it should be integrated throughout the transplantation continuum," De Geest said.

"Smoking is clearly a modifiable risk factor that has a negative impact on transplant outcome," said Dr. Chris Dudley of Southmead Hospital in Bristol, UK, who was not part of the new review.

Smoking may also be a surrogate for socioeconomic status: poorer, less educated people are more likely to smoke and also tend to have worse health outcomes, he told Reuters Health.

"One of the questions is, should we ration transplantation to nonsmokers only, but I don't think that's feasible," Dudley said. "We live in a liberal democracy, for the most part, and that would be thought of as too draconian."

Some patient will quit, or claim to quit, before a transplant and resume smoking after, he said.