WEDNESDAY, Oct. 3 (HealthDay News) -- People who undergo the transplantation of stem cells taken from bone marrow, circulating blood or umbilical cord blood are more likely to develop risk factors for heart disease, such as high blood pressure, diabetes and high cholesterol, a new study contends.

Researchers from the American Society of Hematology noted that patients who were treated with chemotherapy or radiation before such a transplant -- called a "hematopoietic cell transplant," or HCT -- had a significantly higher risk for heart disease later in life.

"While we know that heart disease is a real concern for long-term HCT survivors, small sample sizes and a lack of long-term follow-up in previous studies have only allowed us to look at a small piece of the puzzle of how this chronic condition develops in these patients," the study's first author, Dr. Saro Armenian, medical director of the Pediatric Survivorship Clinic in the Childhood Cancer Survivorship Program at City of Hope in Duarte, Calif., said in a society news release.

"Our study sought to better determine the specific factors before and after transplant that can lead to heart disease in a large group of transplant recipients," Armenian explained.

In conducting the study, the researchers examined the medical records of nearly 1,900 hematopoietic cell transplant recipients to identify factors that could affect their development of risk factors for heart disease. The transplants occurred between 1995 and 2004, and the patients survived for at least one year after the treatment.

The investigators considered the patients' exposure to chemotherapy or radiation before the transplant, the type of hematopoietic cell transplant and whether they were treated for a serious transplant complication known as graft-versus-host disease.

Using the U.S. National Health and Nutrition Examination Survey, the researchers also projected heart disease risk factor rates for the general population.

The study found that high blood pressure, diabetes and high cholesterol were more common among long-term survivors of the blood-forming stem cell transplants.

The risk for developing diabetes was 1.5 times higher for hematopoietic cell transplant survivors who underwent total body radiation. Their risk for high cholesterol was 1.4 times higher. The researchers noted this was true regardless of the type of blood-forming stem cell transplant the patient received.

Although it's unclear why total body radiation increased these patients' risk for diabetes and high cholesterol, previous studies have shown that abdominal radiation may contribute to insulin resistance and an increase in belly fat among cancer patients.

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Stem Cell Transplant May Spur Heart Disease Risk: Study