Occupational Noise Exposure in Relation to Hypertension: A Cross-sectional Study in the Steel Factory

Background: Noise has been acknowledged as one of the most prevailing physical hazard in occupational health and safety. Noise can possess both permanent and temporary health outcomes. The hazardous exposure to occupational noise is generally identified to have aural effects. However in past few years, researches have been carried out to perceive the association between noise exposure and cardiovascular diseases. Yet, the topic has been under controversies regarding its actual relationship or association since there is an existence of other confounders, variables or lifestyle with the exposure which might affect the subsequent disease condition. The results have not been consistent in the studies. Hypertension is one of the most significant etiological factors for cardiovascular diseases. Noise can cause high blood pressure mostly by two ways: either by releasing stress hormones like steroids or by stimulating sympathetic nervous system. China being one of the most rapidly developing countries in the world is having most prominent effect of noise in the daily life since it is a point for most of the goods manufacturing. Various national and international organizations like CDC, OSHA, and NIOSH etc. has recommended various ways to control the noise hazard and its deleterious impact on human health. This research was also done to assess the relationship or association between noise exposure level and prevalence of hypertension in the workers from steel factory in Guangzhou. Aim: The goal of the study was to find out the relationship between occupational noise exposure and prevalence of hypertension regarding its confounders. Methods: A cross-sectional study was carried out to find out the association between noise exposure level ( 90) dBs and hypertension. The data was collected in Guangzhou No.12 Peoples hospital. A sample of 274 workers was taken from the steel factories in Guangzhou. The data was collected through physical examination and questionnaires. For statistical analysis, Chi square test was used in order to compare the variables. Logistic regression analysis was used to test the association between hypertension and the selected variables. Results: As a result, we found out that cumulative noise exposure is associated with hypertension (P=0.004). The total prevalence of 9.8% of hypertension cases were under the noise exposure group of >90 db. The independent association of hypertension was seen after the linear regression analysis as BMI group over weight (odd ratio = -0.090, CI 95%= (-0.005)–(-4.280) with P=0.039 when compared to the reference category of BMI underweight. The correlation of hypertension was also seen with age group (P=0.009), working years and sleeping hours with P=0.030 and P=0.047 respectively. Conclusion: The study showed that the prevalence of hypertension is associated with the occupational noise exposure and highly influenced by BMI group overweight after our final regression analysis. Age group, working years and sleeping hours also showed having some association with the prevalence of hypertension.