Effect of Occupational Noise on Employee Health: A Longitudinal Study.

Objective: This study investigated the long-term health risks associated with occupational noise exposure. By using 9 years of health examination data from a major manufacturing company in Taiwan, this study compared the health indices of employees in noise-intensive and non-noise-intensive work environments.

Methods: A retrospective analysis of 6278 health examination reports spanning 9 years was conducted to compare 20 health indices among 166 employees evenly distributed between noise-intensive and non-noise-intensive workgroups. These employees were carefully matched for sex, age, and work experience. Linear regression models were used to assess the temporal impact of noise exposure on each health index by incorporating a unique range ratio to quantify index fluctuations attributable to noise.

Results: Employees exposed to occupational noise had an increase in platelet count of 16.594 K/µL, with an annual increment of 1.228 K/µL. Moreover, employees in noisy environments exhibited a significant increase in blood urea nitrogen level by 0.438 mg/dL, with an annual increase of 0.171 mg/dL. Additionally, their carcinoembryonic antigen level was significantly increased by 0.187 ng/mL on average, with the annual increase being 0.034 ng/mL. Moreover, increases in systolic blood pressure (2.015 mmHg), heart rate (4.620 beats/min), and white blood cell count (0.536 K/µL) and a decrease in red blood cell count (0.107 M/µL) were discovered to be solely attributable to noise exposure.

Conclusions: Prolonged exposure to high occupational noise levels significantly increases the risk of cardiovascular, renal, and colorectal diseases. This longitudinal study underscores the detrimental health consequences of prolonged noise exposure in occupational settings.