New research is challenging the belief that when it comes to kidney transplants, the younger the age of the donor, the better the organ.

It may also show that transplants using kidneys from live donors could have better outcomes than transplants from deceased donors.

Scientists at the University of British Columbia analyzed kidneys from donors of different ages that were transplanted into patients in different age groups.

They found that if a kidney recipient was 18 to 39, they appeared to benefit from having a kidney from an individual in the same age category. But for those 39 or older, the age of the recipient didn’t really affect the survival of the transplanted kidney.

Researchers also examined the outcomes of patients waiting for kidneys who did not receive donated kidneys.

People waiting for kidney donations from deceased people had a likelihood of receiving a donor of 21 per cent to 66 per cent after a three-year waiting period. They had a six per cent to 27 per cent chance of being excluded from such a transplant after three years due to medical reasons, age and other factors.

The research should help increase participation in living donations as "it alleviates patient concerns about receiving a kidney from an older aged living donor," said lead author John Gill.

The study, appearing online Friday in the Clinical Journal of the American Society Nephrology, will be published in the May issue.

It looked at all adult kidney transplants from living donors performed in the U.S. between January 1998 and December 2003.

Patients were followed until September 2007.