Occupational, Lifestyle, and Medical Risk Factors for Non-Hodgkin Lymphoma: A Case-Control Study in Ethiopia

Background: Non-Hodgkin lymphoma (NHL) is a significant public health concern in Ethiopia. However, data on non-infectious risk factors are scarce. Methods: We conducted an age- and sex-matched hospital-based case-control study at two referral hospitals in Ethiopia, enrolling 207 NHL cases and 405 controls. Self-reported occupational, medical, and lifestyle-related exposures were collected via structured interviews. Conditional logistic regression was used to estimate adjusted odds ratios (AOR) and 95% Confidence Intervals (CIs), adjusting for education and residence. Results: NHL cases were predominantly male (64.3%) with the majority diagnosed between ages 36-65. Low-grade NHL was the most common subtype (56.4%). Rural residence (AOR = 2.62, 95% CI: 1.71-4.0) and lower educational level (OR = 2.08, 95%CI: 1.33-3.15) were significantly associated with NHL. Occupational exposures, including gardening (AOR = 1.68, 95% CI: 1.04-2.2), pesticide use (AOR = 2.14, 95% CI: 1.34-3.40), agricultural work (AOR = 1.76, 95% CI: 1.12-2.83), and keeping farm animals within the household (AOR = 2.41, 95% CI: 1.51-3.84) were linked to higher NHL odds. In contrast, smoking (AOR = 0.31, 95% CI: 0.17-0.55) and alcohol consumption (AOR = 0.55, 95% CI: 0.35-0.87) were inversely associated with NHL. A history of infection requiring hospitalization (AOR = 2.12, 95% CI: 1.15-3.96) and tonsillectomy/uvulectomy (AOR = 2.61, 95% CI: 1.19-5.71) were associated with increased NHL odds. Subgroup analysis revealed stronger associations between occupational exposures and high-grade NHL, while low-grade NHL was linked to tonsillectomy/uvulectomy. Conclusions: Occupational, medical, and lifestyle-related factors are associated with NHL risk in Ethiopia.