Risk factors for Burkitt lymphoma in East African children and minors: A case-control study in malaria-endemic regions in Uganda, Tanzania and Kenya.

Endemic Burkitt lymphoma (eBL) is the most common childhood cancer in sub-Saharan African countries, however, few epidemiologic studies have been undertaken and none attempted enrolling cases from multiple countries. We therefore conducted a population-based case-control study of eBL in children aged 0-15 years old in six regions in Northern Uganda, Northern Tanzania and Western Kenya, enrolling 862 suspected cases and 2,934 population controls (response rates 98.5-100%), and processing ~40,000 vials of samples using standardized protocols. Risk factor questionnaires were administered, and malaria period prevalence was measured using rapid diagnostic tests (RDTs). A total of 80.9% of the recruited cases were diagnosed as eBL; 61.4% confirmed by histology. Associations with eBL risk were computed using logistic regression models adjusted for relevant confounders. Associations common in at least two countries were emphasized. eBL risk was decreased with higher maternal income and paternal education and elevated with history of inpatient malaria treatment >12 months before enrollment. Reporting malaria-attributed fever up to 6 months before enrollment and malaria-RDT positivity at enrollment were associated with decreased eBL risk. Conversely, reporting exposure to mass malaria suppression programs (e.g., indoor residual insecticide) was associated with elevated risk. HIV seropositivity was associated with elevated eBL risk, but the relative impact was small. The study shows that it is feasible to conduct networked, multisite population-based studies of eBL in Africa. eBL was inversely associated with socioeconomic status, positively associated with inpatient malaria treatment 12 months ago and with living in areas targeted for malaria suppression, which support a role of malaria in eBL.

Incidence and trends in Burkitt lymphoma in northern Tanzania from 2000 to 2009.

INTRODUCTION: Burkitt lymphoma (BL) is endemic in parts of Tanzania, but there is scant country or region level data about burden and trends of BL in Tanzania over the past three decades. Here, we update baseline epidemiology of BL in northern Tanzania using recent data. PROCEDURE: Data for childhood BL diagnosed at six hospitals in Mara and Mwanza regions in northern Tanzania during 2000-2009 were compiled. Age, sex, and regional patterns were analyzed. Crude incidence rates of BL were calculated by sex, anatomic site, geographical region, and calendar year. RESULTS: Among 944 cases, 549 (58%) were male (male/female case ratio 1.4:1). Among those with known anatomic site (92%), facial only tumors represented a large proportion of tumors in boys than girls (50% vs. 36%, P < 0.002). Tumors occurred at a younger mean age in boys than girls (6.8 years vs. 7.6 years, P < 0.01). Crude BL incidence was 4.2 per 100,000, but varied by region (3.0 in Mwanza vs. 6.8 in Mara, P = 0.01), by district (1.4-22), by gender (5.0 in boys vs. 4.0 in girls), and by age group (2.0 in 0-4, 7.8 in 5-9, and 3.1 in 10-15 years). BL incidence peaked in 2001 and decreased gradually thereafter. CONCLUSIONS: Our results indicate that male sex, young age, and geographical characteristics are risk factors for BL in Tanzania. BL incidence declined with calendar year, but the significance of this finding is uncertain. Well-designed epidemiological studies of BL in Tanzania may shed light on environmental characteristics underlying these patterns.

African Burkitt lymphoma: age-specific risk and correlations with malaria biomarkers.

African Burkitt lymphoma is an aggressive B-cell, non-Hodgkin lymphoma linked to Plasmodium falciparum malaria. Malaria biomarkers related to onset of African Burkitt lymphoma are unknown. We correlated age-specific patterns of 2,602 cases of African Burkitt lymphoma (60% male, mean ± SD age = 7.1 ± 2.9 years) from Uganda, Ghana, and Tanzania with malaria biomarkers published from these countries. Age-specific patterns of this disease and mean multiplicity of P. falciparum malaria parasites, defined as the average number of distinct genotypes per positive blood sample based on the merozoite surface protein-2 assessed by polymerase chain reaction, were correlated and both peaked between 5 and 9 years. This pattern, which was strong and consistent across regions, contrasted parasite prevalence, which peaked at 2 years and decreased slightly, and geometric mean parasite density, which peaked between 2 and 3 years and decreased sharply. Our findings suggest that concurrent infection with multiple malaria genotypes may be related to onset of African Burkitt lymphoma.