Environmental and occupational risk factors associated with multiple myeloma: a multicenter, hospital-based, matched case-control study.

Introduction: Multiple myeloma (MM), a hematologic malignancy driven by neoplastic plasma cell proliferation, remains insufficiently characterized with respect to occupational and environmental risk factors and their impact on patients' quality of life (QoL). This study explores modifiable exposures in the West Bank, Palestine, and evaluates their associations with MM risk and disease-specific QoL outcomes.

Methods: A multicenter, hospital-based case-control study was conducted between 2018 and 2025, including 227 MM patients and 176 matched controls. Matching was based on age, sex, hospital setting, and admission type. Occupational/environmental exposures including ionizing radiation, cosmetics-related agents, pesticides, organic solvents, and farming were assessed via structured interviews and chart reviews. MM diagnosis adhered to International Myeloma Working Group criteria. QoL was evaluated using the validated EORTC QLQ-MY20 instrument. Multivariable logistic and linear regression analyses were performed, adjusting for clinical confounders using LASSO selection.

Results: Cosmetics-related chemical exposure was independently associated with higher odds of MM (OR = 2.85; 95% CI: 1.56-5.21) and a mixed QoL profile. Specifically, it predicted increased disease symptoms (Coeff = 11.55; 95% CI: 2.82-20.28; p = 0.010), lower treatment side-effects scores (Coeff = -2.17; 95% CI: -8.57 to -0.23; p = 0.049), and a marked decline in future perspective (Coeff = -13.73; 95% CI: -22.88 to -4.58; p = 0.003). Pesticide exposure was significantly linked to lower disease symptom burden (Coeff = -3.77; 95% CI: -12.61 to -2.06; p = 0.041) and better future outlook (Coeff = 10.05; 95% CI: 0.77-19.34; p = 0.034). Meanwhile, organic solvent exposure (carcinogenic-organic compounds) was associated with a decline in future perspective (Coeff = -3.96; 95% CI: -5.70 to -2.62; p = 0.042).

Conclusion: This study highlights cosmetics-related agents, pesticides, and organic solvents as key modifiable risk factors for both MM development and QoL deterioration. Their significant physical and psychological impacts underscore the urgency of integrating preventive occupational health strategies with holistic myeloma care that addresses symptom burden and future outlook.