Occupational pesticide exposure and association of monoclonal gammopathy of undetermined significance in the Western Macroregion of Paraná

BACKGROUND: Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant condition that precedes multiple myeloma and is associated with environmental factors, including pesticide exposure. MATERIALS AND METHODS: This analytical observational study with a cross-sectional design assessed the prevalence of MGUS and its association with occupational pesticide exposure among men aged 50 years or older in the Western Macroregion of Paraná, Brazil. A total of 486 participants were allocated to the exposed group (n = 243) and the unexposed group (n = 243), according to self-report occupational pesticide exposure. All participants completed a standardized sociodemographic and occupational questionnaire and underwent laboratory tests. Comparisons between groups were performed using Pearson's chi-square or Fisher's exact tests. Crude and age-adjusted Poisson regression models were used to estimate prevalence ratios, and logistic regression models were used to investigate factors associated with MGUS. RESULTS: The overall prevalence of MGUS was 4.74% (95% CI: 2.99-7.09) and was higher in the reference group classified as non-occupationally exposed (6.58%) than in the occupationally exposed group (2.47%). Age was associated with higher odds of MGUS (OR = 1.07; p = 0.009), and former smoking was associated with higher odds of MGUS (OR = 2.79; p = 0.038). No significant association was observed between occupational pesticide exposure and MGUS after adjustment. CONCLUSION: No significant association was found between occupational pesticide exposure and MGUS. Age and former smoking were associated with MGUS in the study population. These findings should be interpreted with caution due to the cross-sectional design and limited number of MGUS cases, but contribute to the existing evidence on MGUS prevalence in populations with occupational pesticide exposure and highlight the need for further longitudinal studies.