Association between occupational noise exposure and metabolic dysfunction-associated fatty liver disease: the mediating role of body mass index in automotive manufacturing workers.

BACKGROUND

Occupational noise exposure has been linked to various adverse health outcomes, including metabolic disorders. However, limited evidence exists regarding its association with metabolic dysfunction-associated fatty liver disease (MAFLD). This study aimed to investigate the association between occupational noise exposure and MAFLD among automotive manufacturing workers, providing scientific evidence for the prevention and management of MAFLD in occupational populations.

METHODS

A cross-sectional study involving 3,427 male workers from two automobile manufacturing enterprises in Guangzhou, China, was conducted in 2023. Individual occupational noise exposure levels were assessed via cumulative noise exposure (CNE). MAFLD was diagnosed on the basis of ultrasound imaging and metabolic criteria, including obesity, type 2 diabetes, or metabolic dysregulation. Logistic regression models were used to evaluate the associations between CNE and MAFLD, adjusting for demographic, lifestyle, and clinical covariates. The interaction effects of shift work and hearing protection device use were analyzed. Mediation analysis was used to assess the role of body mass index (BMI) in the relationship between CNE and MAFLD.

RESULTS

According to the continuous models, each 1 dB-year increase in the CNE was associated with a 1.05-fold increased risk of MAFLD (OR: 1.05, 95% CI: 1.02, 1.08). According to the categorical models, workers in the highest CNE quartile (>89.651 dB-years) had a significantly greater risk of MAFLD (OR: 1.50, 95% CI: 1.05, 2.16) than did those in the lowest quartile. Subgroup analyses revealed that the association was more pronounced among workers who did not use hearing protection devices or worked night shifts (p for interaction<0.01). Body mass index (BMI) partially mediated the association between CNE and MAFLD, accounting for 3.48% of the total effect.

CONCLUSION

Occupational noise exposure was associated with higher odds of MAFLD, and BMI partially mediated this association. Night/shift work and hearing protection use affect this relationship. These findings emphasize the need for effective noise control and occupational health interventions to mitigate MAFLD risk among workers exposed to noise.