Use of low-dose aspirin and non-aspirin nonsteroidal anti-inflammatory drugs and risk of glioma: a case–control study

BACKGROUND: Few studies have examined the association between use of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) and risk of glioma and the results have been equivocal. We therefore investigated the influence of NSAID use on glioma risk in a nationwide setting. METHODS: We used national registries in Denmark to identify all patients aged 20–85 years with a first diagnosis of histologically verified glioma during 2000–2009. Each case was matched on birth year and sex to eight population controls using risk-set sampling. We used prescription data to assess NSAID use and classified exposure to low-dose aspirin or non-aspirin (NA) NSAIDs into ever use or long-term use, defined as continuous use for ⩾5 years. Conditional logistic regression was used to compute odds ratios (ORs), with 95% confidence intervals (CIs), for glioma associated with NSAID use, adjusted for potential confounders. RESULTS: A total of 2688 glioma cases and 18 848 population controls were included in the study. Ever use of low-dose aspirin (OR=0.90; 95% CI: 0.77–1.04) or NA-NSAIDs (OR=1.05; 95% CI: 0.96–1.14) was not associated with glioma risk. Compared with never use, long-term use of low-dose aspirin or of NA-NSAIDs was associated with ORs of 0.80 (95% CI: 0.53–1.21) and 1.11 (0.57–2.17), respectively. We observed no clear patterns of risk in stratified analysis according to estimated doses of low-dose aspirin (⩽100 mg, 150 mg). CONCLUSION: We did not find any apparent association between aspirin or NA-NSAID use and risk of glioma, although our results may be consistent with a slight reduction in glioma risk with long-term use of low-dose aspirin.