Abstract 1295: The association between asthma and pediatric brain tumors in neurofibromatosis type 1
Authors: Johnson Kimberly J. , Mueller Nancy , Sharkey Evelyn , Liu Qian , Gutmann David H. 
Published: May 2015

Background. Neurofibromatosis type 1 (NF1) is a common hereditary cancer syndrome, affecting an estimated 1/2,500 people worldwide. NF1 increases the risk of several tumor types, including pediatric brain tumors that affect an estimated 10-20% of individuals. While established risk factors for pediatric brain tumor development in this population have not been elucidated, consistent evidence from non-syndromic populations suggests a strong inverse association between asthma and brain tumors. As such, the objective of this study was to test the hypothesis that asthma is inversely associated with pediatric brain tumors in the NF1 population.

Methods. In this analysis, we employed two data sources. The first dataset was assembled from the international NF1 Patient Registry Initiative (NPRI) (https://nf1registry.wustl.edu/) that enrolled individuals with NF1 over ∼2.5 years. Medical history data were collected through the online registry questionnaire. The second study used private health insurance claims data from 2006-2010 from Thompson Reuters MarketScan to assemble an NF1 group and their claims data on asthma- and brain tumor-related healthcare visits. Diagnoses were determined from ICD-9 codes. The NF1 group was defined by the presence of &gt;2 NF1-related outpatient claims &gt;30 days apart or one NF1-related inpatient claim. Within the NF1 group, individuals were classified as having asthma and/or brain tumors if they had &gt;2 claims for these conditions &gt;30 days apart. The study population for both data sources was limited to subjects who were &lt;18 years old at the time of NPRI or insurance enrollment. Unconditional logistic regression was employed to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between pediatric brain tumors and asthma for both datasets.

Results. A total of 409 individuals with NF1 were included in the analysis using NPRI data, resulting in 119 pediatric brain tumors. After adjusting for birth year, we observed an inverse association between pediatric brain tumors and asthma (OR=0.6; 95% CI 0.4-1.1). In the analysis using MarketScan data, the NF1 group included a total of 3,871 individuals &lt;18 years at the time of insurance enrollment, of which 397 had &gt;2 pediatric brain tumor-related claims. After controlling for number of months enrolled, birth year, and number of healthcare visits, subjects with brain tumor claims were significantly less likely to have asthma claims than those without brain tumor claims (OR=0.5; 95% CI 0.3-0.8).

Conclusions. Similar to findings from non-syndromic populations, the results from this study provide strong epidemiologic evidence for an inverse association between asthma and pediatric brain tumors in the NF1 population.

Acknowledgements. This work was supported by Alex's Lemonade Stand Foundation and NIH CTSA UL1 TR000448.

Citation Format: Kimberly J. Johnson, Nancy Mueller, Evelyn Sharkey, Qian Liu, David H. Gutmann. The association between asthma and pediatric brain tumors in neurofibromatosis type 1. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1295. doi:10.1158/1538-7445.AM2014-1295