Americans who receive a kidney from someone who is not a relative tend to be white, highly educated and live in wealthier neighbourhoods, according to a new study that calls for wider outreach to promote living donation. Researchers say the findings demonstrate that financial and educational barriers to donating a kidney make it harder for the poor and minorities to give or receive an organ. "We`re not doing enough in this country to remove disincentives to living donation," said Dr. Gabriel Danovitch, senior author of the study and director of the kidney and pancreas transplant program at the University of California, Los Angeles. Although medical costs for a live donor are typically covered by health insurance, additional expenses -- such as travel, lodging and time off of work -- are not. The kidney is one of the few organs a person can give away, yet still lead a healthy life afterwards with one remaining kidney. Since the 1990s, advances in immune-suppression have made it safer to receive an organ from someone who is not biologically related. Less-invasive surgery techniques also make it easier to give a kidney. To see who is most likely to take advantage of that opportunity, Danovitch and his colleagues looked back on information about all 39,000 adult kidney transplants in the US from 1997 to 2007 that occurred between a patient and a live donor. They gathered up data on education, race, insurance type, zip code and whether people were related. Spouses and immediate family were considered related, while distant relatives, friends, colleagues and others were considered unrelated. Danovitch`s group found that kidney donations from non-relatives have become more common, rising from seven percent of live donations in 1997 to 26 percent in 2006. In most cases when patients seek a live donor, they look for a match among close family first, and non-relatives second. Sometimes there is no relative able to offer a healthy kidney, however, because a common condition that leads to kidney failure -- polycystic kidney disease -- tends to run in families. Danovitch said that in a few cases organs came from volunteers who had no relationship at all with the transplant recipient, but the vast majority of the time the unrelated donors had an emotional relationship with the patient -- mostly they were friends. His team also found that both unrelated donors and recipients were generally older, likely to live in slightly higher-income neighbourhoods than related donors and recipients and more likely to have completed a college degree. Unrelated-transplant recipients were about 20 percent more likely than the related pairs to be in their 40s or 50s than to be under 40, for example. And they were about 25 percent more likely to be white, than to be black or Hispanic. Thirty-nine percent of kidney recipients who were unrelated to their donors also had college degrees, compared to 35 percent of related recipients. Patients with higher socioeconomic status are probably more likely to have access to potential donors who have similar means and resources, Danovitch`s group writes in their report, published in the Journal of Urology. "It`s not because (people in lower socioeconomic-status groups) care about their loved ones any less, but because they can`t pay for the flight, the hotel, or losing their job," he said. Kidney donors typically have to take six weeks off work after the transplant, said Dr. Arthur Matas, the director of the Renal Transplant Program at the University of Minnesota, who was not involved in the new study. Matas said that informational barriers might explain the finding that recipients of organs from unrelated donors are more likely to have had more formal education. "If you don`t know how to get access to healthcare, then you`re not going to get referred to the tertiary centres that do (living donor) transplants," Matas said. "Formal education level may correlate with awareness of the benefits of living donation, which can affect the willingness to donate and receive a kidney," Danovitch`s team writes. Cultural differences could also factor in to the results, they note. Dr. Amber Reeves-Daniel, the medical director of abdominal organ transplant at Wake Forest Baptist Medical Centre in Winston-Salem, said she`s made a similar observation at her centre -- that African American transplant recipients almost always receive a live donor kidney from a relative. "I think there`s a sense of closeness in the African American family structure of, `we`re going to make this work,`" said Reeves-Daniel, who was not involved in the study. "If that doesn`t work out, then they say, `I would just get a kidney from a deceased donor,`" rather than seek out a kidney donor outside of the family. The trouble with waiting for a kidney from a deceased donor is that hopeful recipients far outnumber the availability of organs. According to the Organ Procurement and Transplantation Network, 91,000 people are waiting for a kidney. The United Network for Organ Sharing (UNOS) is in charge of the waiting list for deceased-donor organs. UNOS would not comment on the study because the organization does not allocate living-donor organs. "One of the great benefits of living kidney donor transplant is you don`t have to wait," said Dr. John Friedewald at Northwestern University Feinberg School of Medicine in Chicago, who did not participate in the research. While there are health risks for people who donate a kidney, Danovitch said he`d like to see more people have the chance to donate if they want to. That might include finding ways to reimburse people for the costs that insurance companies typically don`t cover, such as time off work. Low-income organ donors can seek some financial help from the National Living Donor Assistance Centre, a federally-funded program to help cover the costs of providing an organ. Danovitch said in addition to the financial hurdles, the educational barriers also need to be addressed to make sure all kidney donors and recipients have an equal opportunity to share.