Abstract
Background: Noise is a widespread occupational hazardous factor affecting the health of workers in occupational health field. Noise-induced hearing loss (NIHL) and hypertension are the important biological adverse effects caused by occupational noise exposure. This study aimed to determine the binaural high frequency (3, 4, and 6 kHz) threshold on average (BHFTA) and levels of systolic blood pressure (SBP) and diastolic blood pressure (DBP), to assess the prevalence of NIHL and hypertension and determine the factors influencing the risk of both, and to evaluate the association between NIHL and hypertension among occupational noise-exposed workers. Methods: Questionnaire and occupational health checkup were performed to collect the personal information and physical examination data. Finally, baseline data from 42,588 occupational noise-exposed workers were analyzed. Noise intensity in the workplaces was measured using sound level meter. Pure tone audiometry (PTA) was measured at 3, 4 and 6 kHz using diagnostic audiometer. Moreover, blood pressure level was measured using automated sphygmomanometer. Results: The mean levels of BHFTA, SBP, and DBP were 23.09 ± 11.32 dB, 126.85 ± 15.94 mm Hg, 79.94 ± 11.61 mm Hg. Of the 42,588 subjects, the prevalence of NIHL and hypertension were 24.38% (n = 10,383) and 25.40% (n = 10,816). The results suggested that higher risk of NIHL and hypertension were more likely to be the subgroups of male gender, aged > 35 years, noise exposure time > 5 years, noise exposure level > 85 dB (A) and smoking. The BHFTA, SBP, and DBP levels increased with the age, noise exposure time and exposure level (Ptrend < 0.001). Besides, similar trends were also observed in the prevalence of NIHL and hypertension. Furthermore, there was a significant association of NIHL with hypertension. We found that 32.25% (n = 3,348) workers with NIHL had hypertension. The mean levels of SBP and DBP in NIHL workers were significantly higher than those with normal hearing (P < 0.001). Besides, workers with NIHL had a significantly higher risk of developing hypertension than normal hearing workers (adjusted OR = 1.07, 95%CI = 1.02-1.13). Conclusion: Our current findings suggest that the prevalence of NIHL and hypertension are high in the studied workers and occupational noise exposure is an important factor. Therefore, it is urgent to reduce noise exposure in the workplaces and to strengthen industrial noise monitoring.
Associations of blood pressure and arterial compliance with occupational noise exposure in female workers of textile mill
