[Effects of carbon disulfide on blood pressure and electrocardiogram for workers exposed to levels below the national maximum allowable concentration].

OBJECTIVE

To study the effects of carbon disulfide exposure within the national maximum allowable concentration(MAC) on blood pressure and electrocardiogram, and associations with selected factors.

METHODS

Workers in a chemical fiber factory were divided into two groups based on the type of work: a high exposure group (HEG) of 821 individuals and a low exposure group (LEG) of 259. The CS2 concentration at workplace was controlled under the national MAC. A set of 250 randomly selected people taking routine physical check-ups in the same period and hospital constituted the control group. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured on the arm, and the pulse pressure (PP) and mean arterial blood pressure (MABP) were calculated based on SBP and DBP. The blood pressure data, along with the results of the routine 12-lead electrocardiography taken at rest and records on gender, age, years of work, type of work, and concentrations of triglycerol, cholesterol, and glucose in blood, were compiled for analyses. Risk factors upon CS2 exposure for the increase of blood pressure and occurrence of electrocardiogram abnormalities were identified and rationalized.

RESULTS

Significant difference (P < 0.01) in the average values of SBP, DBP, MABP, and the corresponding abnormality incident rates was found between HEG and LEG, and between HEG and the control group. For both HEG and LEG, the incident rate of DBP abnormality (high DBP) is nearly two times as high as that of SBP. Type of work is the largest risk factor in both the high SBP and high DBP subgroups, with odds ratios (OR) of 2.086 and 2.331 respectively, and high CS2 exposure presents more than double the risk than low exposure. On the incident rate of ECG abnormalities, both exposure groups are significantly different (P < 0.01) to the control group. High SBP in LEG and high DBP in HEG were found to be significant risk factors (OR = 3.531 and 1.638 respectively), while blood glucose appears to be a protective factor (OR = 0.747), appealing to further investigation. Meanwhile, factors like years of work and cholesterol were found to be risk factors in the high SBP subgroup with low exposure, and in the high DBP subgroup with high exposure. Within HEG, high DBP is the only blood pressure-related risk factor found for the incident of left ventricular high voltage (OR = 4.140), as is high SBP for LEG (OR = 4.776). High PP is the only risk factor found for repolarization disturbances within LEG (OR = 20.417). While blood sugar is a risk factor for origin disturbances, it is a protection factor for left ventricular high voltage (OR = 0.633).

CONCLUSION

The damage of CS2 done to the cardiovascular system is a gradual process. Both early and very low level exposures are detrimental to the human circulatory system. Below the National MAC limit, the toxic effect of CS2 to the cardiovascular system increases with time and level of exposure. The effect of CS2 on DBP is more significant than on SBP, which indicates that CS2 may affect peripheral resistant blood vessels more than the artery. The abnormalities of ECG of workers exposed to CS2 are not only the result of high blood pressure on the heart, but also of the direct toxicity of CS2 on heart and blood vessels.