Objective: The objective of the present study was to evaluate the effects of occupational exposure to over-concentrations of some organic solvents on the prevalence of arterial hypertension (AH) and pathologic changes in electrocardiography (ECG).
Methods: We studied 345 workers (250 men) aged between 20 and 60 years at a petrochemical factory, and 345 age- and sex-matched controls with no occupational contact with chemical and physical factors. According to the main chemical pollutants in the working environment, the exposed subjects were divided into three groups: group 1, exposed to benzene; group 2, exposed to xylene and benzene, and group 3, exposed to phenol. Physical examination of the heart and routine resting electrocardiography with 12 leads were performed. The degree of AH was determined according to the classification of the American Heart Association (JNC- V, 1993). Statistical analysis was carried out with a SPSS software package.
Results: The mean values of systolic and diastolic blood pressure and the prevalence of AH were significantly higher than in control groups 1 and 2. The prevalence of AH was 30.51% [OR = 2.44; 95% confidence interval (CI) 1.24-4.85; P = 0.0054] in group 1 and 27.92% (OR = 2.00; 95% CI 1.11-3.61; P = 0.0136) in group 2. The same relationship was found for the prevalence of ECG abnormalities: group 1, 17.7% (OR = 2.34; 95% CI 0.99-5.63; P = 0.0344) and group 2, 18.83% (OR = 2.75; 95% CI 1.28-5.97; P = 0.0044). The supraventricular and ventricular ectopic beats were the most frequent, followed by conduction defects and repolarization disturbances. In group 3, the prevalence of AH (23.29%) and ECG changes (13.7%) were higher than in the controls, but the differences were not significant. A significant correlation between the length of service and systolic and diastolic blood pressure (after controlling for major cardiovascular risk factors) was found in groups 1 and 2.
Conclusions: These results show that those workers occupationally exposed to high concentrations of benzene and xylene have an increased prevalence of AH and pathologic changes in ECG. There was no convincing evidence of increased cardiovascular risk associated with occupational exposure to phenol.