Prevalence and Predictors of Hematological Abnormalities among Automotive Mechanics Working in Cotonou and Neighboring Cities, Benin

Background: Automotive mechanics in low-resource settings face chronic exposure to genotoxic agents, and occupational exposure to chemical hazards in workshops has been associated with hematological toxicity; however, evidence from Benin remains limited. This study aimed to characterize the occupational profile of informal automotive mechanics in Benin and examine associations between work specialty, employment duration, personal protective equipment (PPE) use, multi-trade exposure, and hematological abnormalities. Methods: We conducted a cross-sectional study (June-December 2024) among male mechanics in Cotonou and nearby cities in southern Benin. Sociodemographic characteristics, occupational history, PPE use, and workshop exposure type were collected using standardized questionnaires. Peripheral blood was analyzed with an automated hematology analyzer. Hematological abnormalities were defined using both internationally validated and locally recommended thresholds, and multivariable logistic regression identified independent predictors. Results: The cohort included 298 male mechanics: 236 automobile, 29 diesel, and 33 motorcycle mechanics. Overall PPE use was low (19.4%). Significant differences across specialties were observed for red blood cell indices and leukocyte subsets. Diesel mechanics had the highest prevalence of microcytic normochromic anemia (27.6%, p = 0.004), and automobile mechanics had the highest macrocytosis prevalence (17.9%, p = 0.036). Longer employment duration was associated with higher MCH/MCHC, lower platelet counts, and higher thrombocytopenia frequency, while microcytosis was more frequent among workers with ≤22 years employment. In contrast, microcytosis was markedly less frequent among PPE users (5.5% vs. 16.6%, p = 0.034). In multivariable analyses, PPE use was associated with lower odds of microcytosis (OR = 0.16); older age was associated with macrocytosis (OR = 1.09/year), neutropenia (OR = 1.04/year), and leukopenia (OR = 1.05/year); longer work duration was associated with increased thrombocytopenia odds (OR = 1.04/year). Multi-trade workshop mechanics showed a nonsignificant trend toward increased hematological risk. Conclusion: Automotive mechanics in Benin show measurable hematological alterations varying by specialty, exposure intensity, and employment length. These results highlight the need for routine occupational health surveillance and targeted prevention measures, prioritizing PPE use and safer work practices. However, the cross-sectional design precludes causal inference;