August 5, 2012
Allergies Linked To Reduced Risk Of Brain Tumors
redOrbit Staff & Wire Reports - Your Universe Online
An international team of scientists has discovered evidence supporting the theory that people with allergies could have a reduced risk of contracting a serious form of cancer that starts in the brain.
In the study, which has been published online in the Journal of the National Cancer Institute, the researchers analyzed stored blood samples from both male and female patients who later went on to develop glioma, which form from glial cells. They found that subjects whose blood samples contained allergy-related antibodies had nearly half the risk of developing these tumors two decades later versus those who lacked indicators of allergies.
“This is our most important finding,” Judith Schwartzbaum, lead author of the study and an associate professor of epidemiology at Ohio State University (OSU), said in a statement. “The longer before glioma diagnosis that the effect of allergies is present, the less likely it is that the tumor is suppressing allergies. Seeing this association so long before tumor diagnosis suggests that antibodies or some aspect of allergy is reducing tumor risk."
“It could be that in allergic people, higher levels of circulating antibodies may stimulate the immune system, and that could lower the risk of glioma,” she added. “Absence of allergy is the strongest risk factor identified so far for this brain tumor, and there is still more to understand about how this association works.”
The study revealed that the reduced risk was found to be greater in women than in men, and strengthened the theory that there is something about allergies that reduces the risk of developing this form of cancer.
Much of the previous research on the study had been based on self-reporting of a person's history of allergy from glioma patients, and this is said to be the first study to have access to blood samples taken more than 20 years before each person's cancer diagnosis.
"The current study also suggested that women whose blood samples tested positive for specific allergy antibodies had at least a 50 percent lower risk for the most serious and common type of these tumors, called glioblastoma," the university said. "This effect for specific antibodies was not seen in men. However, men who tested positive for both specific antibodies and antibodies of unknown function had a 20 percent lower risk of this tumor than did men who tested negative."
"Glioblastomas constitute up to 60 percent of adult tumors starting in the brain in the United States, affecting an estimated 3 in 100,000 people," they added. "Patients who undergo surgery, radiation and chemotherapy survive, on average, for about one year, with fewer than a quarter of patients surviving up to two years and fewer than 10 percent surviving up to five years."
The research was funded by National Cancer Institute, the National Institutes of Health (NIH) and a Research Enhancement and Assistance Program grant from the OSU Comprehensive Cancer Center. Co-authors on the study included Bo Ding, Anders Ahlbom and Maria Feychting of the Karolinska Institutet (KI) in Sweden; Tom Borge Johannesen and Tom Grimsrud of the Cancer Registry of Norway; Liv Osnes of Ulleval University Hospital in Norway; and Linda Karavodin of Karavodin Preclinical Consulting in California.