Atopy Linked to Lower Risk of Glioma

NEW YORK NOV 02, 2007 (Reuters Health) - A history of atopic disease is inversely associated with the risk of glioma, according to findings published in the October 17th issue of the Journal of the National Cancer Institute.

Little is known about the etiology of glioma, note Dr. Eleni Linos, of Harvard School of Public Health, Boston, Massachusetts, and colleagues. "Atopic diseases are on the rise in western populations, with increasing interest in their long-term health consequences," they point out. "An inverse association between atopy and the risk of glioma has been observed."

To investigate further, the researchers conducted a systematic review and meta-analysis of published case-control and cohort studies that quantified the association between asthma, eczema, or allergy and a medically confirmed diagnosis of glioma or meningioma.

A total of eight studies with 3450 patients diagnosed with glioma and 1070 patients with meningioma were included in the analysis.

Compared to those with no history of atopic disease, subjects with a history of an atopic condition had pooled relative risks of glioma of 0.61 for allergy, 0.68 for asthma, and 0.69 for eczema.

"The pooled relative risk estimate for all five studies without any proxy reporting remained inverse and statistically significant (RR = 0.66)," Dr. Linos and colleagues found. They note that publication bias was an unlikely explanation for the inverse association because the relationship persisted in a sensitivity analysis. vThere was no overall significant association between atopy and meningioma. However, the information on this disease was limited and heterogeneous.

The team suggests that the inverse association between atopy and glioma risk supports the "biologically plausible proposition" that it reflects "a broader association between heightened immunity and intracranial tumors."

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