Tuesday, March 9, 2010
Giving a kidney carries few health risks, with donors living just as long or sometimes even longer than those who don't donate, the largest study to date of donors has found.
Using data on more than 80,000 U.S. residents who donated a kidney between 1994 and 2009, researchers found that donors lived now as long as people who were matched for age, gender, ethnic background and other health and demographic factors but who did not donate a kidney.
The normal length of follow-up was more than six years, although researchers had more than 12 years of data on 10,000 donors, according to the analysis in the March 10 issue of the Journal of the American Medical Association.
"On average, if you compare someone who has donated and lives with one kidney and compare them to someone just like them who lives with two kidneys, there is no increased risk of mortality," said study author Dr. Dorry Segev, a transplant surgeon and director of clinical research in transplant surgery at Johns Hopkins University School of Medicine in Baltimore.
Each year, about 6,000 living donors in the United States have a kidney removed to save another. About half donate to save a blood relative, Segev said. The other half donate to a friend or loved one, such as a spouse. A small number, about 100 a year, donate a kidney to save a stranger's life, Segev said.
"People who donate kidneys are heroes," Segev said. "They take risks for the direct benefit of another person."
In the study, researchers examined data from the United Network for Organ Sharing (UNOS) national registry and compared it to data on more than 9,000 participants in the third National Health and Nutrition Examination Survey.
While kidney donation is very safe, it's not totally without risk, the researchers noted. About 25 donors died within 90 days of the operation, putting the risk of death at 3.1 per 10,000 donors compared to 0.4 per 10,000 people who did not donate.
Although the researchers did not specifically study cause of death, complications from kidney removal could include major bleeding, reactions to anesthesia or blood clots, similar to those that could occur with any surgery, Segev said.
Men had higher surgical mortality than women, and blacks were more likely to die than whites or Hispanics, as were donors with high blood pressure.
"There is a three in 10,000 chance you will die from the operation. That is a real risk," Segev said. "While the risk is not zero, it happens to be one of the safest operations you can ever possibly have."
For comparison, the risk of death following gallbladder removal, also measured to be among the safest operations, is 18 per 10,000.
One year following the donation, the risk of death among those who donated was the same as those who didn't donate. And beyond that, donors had a similar -- and even a bit lower -- risk of dying as those who didn't donate. Five years out, the risk of death was 0.4 per 10,000 donors and 0.9 per 10,000 non-donors. Twelve years out, the risk of dying was 1.5 per 10,000 donors and 2.9 per 10,000 non-donors, according to the report.
There are two likely reasons why some people with one kidney may live longer than those with two, said Dr. Matthew Cooper, chairman of the UNOS living donor committee and director of kidney transplant and clinical research at University of Maryland School of Medicine.
One enlightenment is that those who donate, knowing they have only one kidney, see a doctor more frequently and take better care of themselves. Another possibility is that donors go through a rigorous screening process, which may mean healthier people are selected to begin with, Cooper explained.
"This study reaffirms what many of us have read in the transplant literature and recognize in our own practices," Cooper said. "Kidney donation is a safe process in the hands of a responsible transplant center that values the long-term health of living donors."
Still, the study authors noted that it's important to continue to monitor and gather data on donors over the long term. The national registry includes health information only up to a year or two post-transplant. The researchers used the Social Security Death Master File to determine who died, but could not study quality of life or any other health issues that might have developed.
"In that long gap of time between one year and many decades after the surgery, we don't have a lot of information about what happens with living donors," Cooper said.
Previous research has also shown kidney donation to be overwhelmingly safe. A study published in 2009 in the New England Journal of Medicine tracked nearly 3,700 kidney donors from as far back as 1963 and found their life expectancy was the same as those who didn't donate.
Monday, February 22, 2010
Slaving over a hot stove -- make that a hot gas stove -- might raise your risk for certain types of cancer.
Researchers in Norway have found that cooking with gas produces more potentially destructive fumes than electric cooking.
But, in a report published online Feb. 17 in Occupational and Environmental Medicine, they also point out that professional chiefs and cooks are more at risk than the normal at-home cook.
"The risk to average at-home cookers is low, at least under Norwegian conditions, where most homes have a kitchen exhaust fan," said study author Ann Kristin Sjaastad, who's with the industrial economics and technology management department in the division of health environment and security at the Norwegian University of Science and Technology in Trondheim. "Yes, professional chiefs/cooks are most at risk, but further studies are essential to estimate their risk level."
The International Agency for Research on Cancer has classified cooking fumes from frying at high temperatures as "probably carcinogenic." The fumes have been found to have polycyclic aromatic hydrocarbons (PAHs), heterocyclic amines, higher and mutated aldehydes, and fine and ultrafine particles.
Regardless of the level of risk, cooks should follow certain "safe cooking" guidelines, said Dr. Lisa Ganjhu, an presence physician in the division of gastroenterology and liver diseases at St. Luke's-Roosevelt Hospital in New York City.
Wednesday, February 10, 2010
Researchers report that they've discovered the origin of strains of the AIDS virus that affect gay and bisexual men.
"By knowing the origin of the transmitted virus, scientists may be able to expand new vaccines, vaginal microbicides and drugs to avoid the spread of sexually transmitted HIV," study author Dr. Davey Smith, an associate lecturer of medicine at the University of California San Diego.
At subject is the HIV in semen, which is made up of seminal cells and liquid called seminal plasma. HIV particles with RNA inside exist in the fluid, while the decisive cells hold the DNA of HIV, the study authors explained.
The researchers used a type of heritable analysis to study men who had sexually transmitted their HIV to other men.
"Until now, it had not been recognized whether HIV RNA or DNA is transmitted during sex," said Smith. "By analyzing the genetic differences between these two forms and the virus that was eventually transmitted to newly infected individuals; we found that it was the HIV RNA form present in seminal plasma that was transmitted."
What about HIV transmission to women? "Since the vast popular of women are infected with HIV by exposure to the virus in semen, HIV RNA in the seminal plasma is the possible culprit, but this needs to be confirmed.
