Background: The present study investigated the effects of exposure to noise and whole body vibration (WBV) on the levels of sex hormones in an automobile parts manufacturing plant.
Methods: The level of workers' exposure (n=162) to each of the mentioned stressors, was measured through standard methods and for each person the time-weighted average (TWA) of exposure was calculated. In order to determine serum sex hormones (free testosterone, LH and FSH), blood samples were taken from all participants after 8-10 hours of fasting between 7-9 am and then the blood samples were analyzed by ELISA method.
Results: In general, regarding testosterone as the main male sex hormone, only 49% of the participants were in the normal range. In total of three sections, the lowest mean testosterone levels was observed in the third exposure group (WBV>1.93 m/s2; noise >92.69 dB) of the studied stressor, however, only the difference in testosterone levels between the three different groups of exposure to noise was statistically significant (P = 0.001). The relationship between demographic variables and levels of noise and WBV exposure with sex hormones was not linear and only the relationship between noise exposure and testosterone levels was statistically significant (R = -0.201, P = 0.013).
Conclusion: According to the results of Logistic Regression, the WBV had the greatest effect on testosterone levels as the main male hormone. However, according to the results of the correlation test, only the relationship between noise exposure and testosterone levels is statistically significant.