RESUMO
PURPOSE: The aim of this study was to measure individual exposure to noise and its effect on the levels of lipid peroxidation and enzymatic antioxidant defense. METHODS: In this cross-sectional study, 94 male workers working in a food factory in Shahroud, Iran, were selected as the case group and 112 people were also included as the control group. The level of exposure to noise was measured using a dosimeter and the equivalent level was calculated. The levels of malondialdehyde (MDA), catalase (Cat), superoxide dismutase (SOD), and Total Antioxidant Capacity (TAC) were measured in the serum samples of all participants. Independent t test, one-way ANOVA, and multivariate linear regression were used to analyze the data. RESULTS: The levels of MDA, Cat, and TAC were significantly higher in staff exposed to noise than in the controls. The starch and warehouse units' staff were exposed to the highest (99.3 ± 3.23 dB) and lowest (77.1 ± 9.68 dB) mean levels of sound pressure. Based on the linear regression model, noise exposure level was the most important predictor variable for levels of MDA (ß = 0.48, CI 95% = 0.04-0.93), Cat (ß = 0.43, CI 95% = 0.05-0.83), and TAC (ß = 0.11, CI 95% = 0.06-0.16). CONCLUSIONS: Noise exposure increases the production of free radicals. As exposure rate increases, the levels of MDA, Cat, and TAC enzymes increase as well.