Effects of antihistamine and anti-inflammatory medication use on risk of specific glioma histologies.

Several studies have shown a decrease in glioma risk associated with a personal history of allergic conditions and the medications used to treat the symptoms. However, few studies have been able to examine risk within histological subgroups of glioma. Case-control data from M. D. Anderson Cancer Center and University of California, San Francisco were pooled to conduct the analysis stratified by histological subtype. A risk prediction model considering inflammation-related variables and antihistamine use was built using logistic regression. Of the subtypes examined, long-term antihistamine use was associated with increased risk of anaplastic gliomas, especially when length of use was considered in conjunction with history of asthma or allergy. Anaplastic cases with no history of asthma or allergy were 2.94 times more likely than controls to report antihistamine use for 10 years or more; whereas anaplastic cases with a history of asthma or allergy were 2.34 times more likely than controls to report antihistamine use for 10 years or more. Furthermore, anti-inflammatory medication use was associated with a protective effect against glioblastoma (OR = 0.80; 95% CI: 0.65, 0.99), especially among individuals with no history of asthma or allergies. No statistically significant effects of anti-inflammatory drugs or antihistamines were evident for the other histological subtypes. Thus, modulation of the immune system by the use of common drugs, such as antihistamines or nonsteroidal anti-inflammatory drugs, may contribute to the development of certain types of brain tumors.