ABSTRACT
INTRODUCTION: Childhood brain tumours (CBTs) are the second most common type of cancer in individuals aged 0-24 years globally and cause significant morbidity and mortality. CBT aetiology remains poorly understood, however previous studies found higher CBT incidence in high-income countries (HIC) compared to low-middle income countries (LMIC), suggesting a positive relationship between incidence and wealth. MATERIALS & METHODS: Aggregated data from Cancer Incidence in Five Continents (CI5) were used to explore CBT epidemiology. Incidence rate ratios (IRR) compared CBT rates between twenty-five geographically and economically diverse countries. The relationship between incidence and economic development was explored using linear regression models and Spearman's rank correlation tests. Trends in CBT incidence between 1978 and 2012 were investigated using average annual percentage changes (AAPC). RESULTS: CBT incidence was highest in North America and lowest in Africa. CBT incidence rates increased significantly with increasing GDP per capita (p = 0.006). Gini index was significantly negatively associated with CBT incidence. Incidence decreased with increasing income inequality within countries, indicated by higher Gini indices (p = 0.040). Increasing and decreasing CBT incidence trends were observed within individual countries, although only Italy (p = 0.02) and New Zealand (p < 0.005) experienced statistically significant changes over time. CONCLUSIONS: The excess disease found in HIC may be explained by environmental risk factor exposure increasing CBT risk in wealthy populations. However, systematic limitations of substandard cancer detection and reporting in LMIC may mean incidence disparities result from misinformation bias rather than genuine differences in risk factor exposure. Further research is required to comprehensively describe CBT epidemiology and explain study findings.
