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Many heart transplant centers rule out cardiac transplants for people older than 65. But a new study from Columbia University Medical Center finds that heart recipients 65 or older do as well as younger recipients when it comes to survival, organ rejection, infection and length of hospital stay.

The study compared 63 patients over age 65 with the same number of patients between the ages of 18 and 65 in the first 10 years post-transplant. No significant health differences were found in the groups, pre-transplant, in terms of diabetes, high blood pressure, lung disease, or vascular disease.

Postoperative intensive care unit stay and overall hospital stay were similar for the two groups. There were no statistically significant differences between the groups in freedom from infection or rejection at one, three, or five years after the transplant. The incidence of transplant coronary artery disease, however, where the presence of atherosclerosis affects the transplant and the grafted vessels, was higher in the older group.

"Our results show age alone should not preclude an older person from getting a transplant," says Dr. Mehmet Oz, professor of surgery and one of the paper's authors. "A person over 65 should receive a careful evaluation similar to what younger patients get when being considered for a transplant." The study was published in the December Annals of Thoracic Surgery.

People are living longer, which translates into an increased need for cardiac surgical procedures, including transplants in the elderly, says Dr. Oz. He and his colleagues now are looking to determine the safe upper age limit for heart transplants by evaluating those who receive a new heart after age 70. They are also analyzing the improvements in quality of life for younger and older recipients.

–Matthew Dougherty

Tuberculosis rates in the United States have declined overall but health care workers in clinical microbiology laboratories still have an increased risk of becoming infected with Mycobacteria tuberculosis because of their contact with potentially infectious laboratory specimens. Few studies in the United States have focused on latent TB infection in hospital and other medical microbiology labs.

Now a new study by CUMC and the Centers for Disease Control and Prevention indicates that lab workers working with mycobacteriology specimens have higher rates of latent tuberculosis infection when compared with other laboratory workers. In a study of 342 New York City laboratory health care workers, 57 percent had a positive skin test for TB in the past. Only 20 percent of these workers had received isoniazid treatment to prevent active TB, despite the fact that the majority of participating hospitals provided diagnostic and treatment services.

Higher treatment rates are desirable because latent TB infection can convert into the active form, says Dr. Lisa Saiman, professor of clinical pediatrics and senior author of the study. "We are winning the battle because case rates in the general U.S. population have gone down and are now stable," she says. "But we need constant vigilance to monitor healthcare workers for conversion and possibly for active TB. Lab workers who develop active TB are also a possible transmission source to their families and co-workers."

Dr. Saiman and her colleagues found that age, foreign birth, BCG immunization — a TB immunization — and employment in a mycobacteriology lab (mycobacteria are the organisms that cause TB) were risk factors associated with latent TB. Gender, length of employment, and the number of specimens processed by the lab that grew Mycobacteria tuberculosis were not significant risk factors for latent TB infection. Only one worker in the study had developed active TB following a laboratory exposure.

She and her fellow researchers interviewed lab workers and sent questionnaires to the lab directors and occupational health service directors at the lab sites. The 19 sites that participated consisted of 18 clinical microbiology labs within hospitals and one research lab — all of which required separate Institutional Review Board approvals to participate in the study, says Elizabeth Garber, project coordinator in pediatrics and the first author of the paper.

The CDC funded the study with the New York City Department of Health and Mental Hygiene because its researchers wanted to know the TB burden among lab workers. New York was a logical place to start because it has among the highest case rates in the nation, Dr. Saiman says.

–Matthew Dougherty

New York City subway riders endure many unpleasant things during their commutes: packed trains, ear-piercing brakes and an array of odors.

They also breathe in levels of some metals that are 100 times higher than typical neighborhood levels, according to new research by a team of scientists from the Mailman School of Public Health, Columbia's Earth Institute, Columbia's Lamont-Doherty Earth Observatory, and Harvard.

Though that may seem high, the levels are still 1,000 times lower than the Occupational Safety and Health Administration's permissible exposure limit guidelines for workers.

"There's no evidence that these levels are a health risk and the findings in no way suggest that people should avoid riding the subway," says the study's lead author, Dr. Steven Chillrud, a research scientist at Lamont-Doherty Earth Observatory. The metal exposure comes from steel dust generated by the grinding between the subway's wheels and rails.

"But it's worth following up on because of the chronic nature of the exposure," he adds. More researchers, he says, are getting interested in the potential health effects of long-term exposures to low levels of hazardous air pollutants. Their study, to be published in an upcoming issue of Environmental Science & Technology, was designed to measure teenagers' exposures to current ambient levels of pollutants in urban areas.

The researchers measured the exposure to air pollutants with the help of high school students at the A. Philip Randolph Academy in northern Manhattan. The students carried air monitors for two days in their backpacks and also measured pollutants in their homes and neighborhoods.

When the researchers analyzed that data, they noticed students who took the subway to school were exposed to higher manganese, iron, and chromium levels than students who did not. Further sampling of the subway's platforms and trains confirmed that most of the students' exposure to the three metals came from the subway and not their homes and neighborhoods.

The research is part of a larger study of air pollutants in New York City and Los Angeles run by Dr. Patrick Kinney, associate professor of environmental health sciences at the Mailman School.

Funds for this research were provided by the Mickey Leland National Urban Air Toxics Center and the NIEHS Center for Environmental Health in Northern Manhattan.

–Susan Conova