Effects Of Exposure To Electromagnetic Fields On Blood Parameters Of Eiectric Utility Workers

ObjectiveOwing to high utilization of modern electrical systems such as wireless technologies, home electronic appliances, power lines, electric generators and motors in our daily life and workplace, exposure to electromagnetic field (EMF) becomes inevitable.While whether the EMFs emitting from these appliances were harm to our health is still not clear. EMF exposure is more serious in an electric power plant. Evaluation the influence of EMF exposure is helpful to formulate the reasonable standard and improve the occupational environment. Therefore, our study aims to evaluate effects of EMF exposure both on serum lipid levels and blood cells in an electric utility workers.MethodsMaterials and Electromagnetic Radiation ExposureThis is a cross-sectional study. We recruited1073subjects according to the inclusion and exclusion criteria in an electric power plant in Zhejiang province, China, in2011. A well-structured questionnaire was applied to obtain relevant information, including socio-demographic characteristics, lifestyle factors and EMF exposures. Specimens of vein blood were sampled for all participants in2010and2011. Blood parameters including serum lipids indicator and blood cell parameters were detected. Serum lipids included total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and triglyceride (TG)). Low density lipoprotein cholesterol (LDL-C) was calculated according to Friedwald formula:LDL-C=TC-(HDL-C+TG/2.17). The blood cell parameters included red blood cell count, packed cell volume, mean corpuscular hemoglobin, red blood cell distribution width, eosinophil count and so on. All parameters were in the normal reference ranges. Additionally, out of the subjects in2011,544participants had the available data of serum lipids measured in regular health examination in2010. EMF included power frequency EMF (PF-EMF) and radio frequency EMF (RF-EMF) in our study. PF-EMF exposure was primarily assessed on the basis of job titles, job description and the conventional measured data from an electric power plant. In order to confirm whether it was appropriate for the assessment of occupational EMF exposure provided by the power plant, we measured intensity of occupational EMF in some main activity areas of workers, including rest room, workshop and so on. Intensity of occupational EMF was measured at each measuring site according to environmental protection industry standards of the People’s Republic of China (1996), which named the Guidelines on Management of Radioactive Environmental Protection Electromagnetic Radiation Monitoring Instruments and Methods (HJ/T10.2-96). In addition, occupation related EMF variables, including employment duration, daily occupational exposure time, walkie talkie, mobile phone fee and electric fee were assessed by a series of relevant questions.All subjects were classified into high exposure group and low exposure group. Intensity of occupational EMF in the high exposure group was higher than those in the low exposure group. Intensity of EMF in the low exposure group was similar with the general population. 2. Statistical AnalysisResults of statistical analysis including two sections (serum lipids and routine blood). Comparisons of socio-demographic characteristics and EMF variables between high EMF exposure group and low EMF exposure group were conducted with Pearson’s chi-square test and Student’s t-test. Maybe workers in the same workshop may be connection with each other, comparisons of hematologic parameters between two groups were analyzed using Generalized Estimating Equation model (GEE) and dichotomy method, after adjustment for potential confounding factors including age, gender, body mass index (BMI), marital status, education level, labor intensity, tea drinking, alcohol drinking, cigarette smoking, work stress and workshops. According to the median, employment duration, daily occupational exposure time, electric fee and mobile phone fee were divided into binary variable in the dichotomy analysis. Due to the different number of subjects in the sections of serum lipids and blood cells, median of employment duration was24and22years in2010and2011, respectively. Moreover, the effects of occupational EMF exposure on serum lipids parameters were repeated evaluation using data of2010. All analyses were performed using Statistical Analysis System software version9.2(SAS Institute Inc, Cary, North Carolina). The significantly statistical threshold was P value less than0.0125for part Ⅰ and less than0.003for part Ⅱ, with adjustment according to the different statistical analyses. Power value was performed using Power and Sample Size Calculation version3.1.2(Vanderbilt Biostatistics Wiki, Nashville, US) in part Ⅱ.ResultsPart Ⅰ Effects of EMF Exposure on Serum Lipids Parameters1.875subjects (693males and182females) aged between22to60years were included in this section. High exposure group had more males, married, lower educational level, higher work stress, more labor intensity, and more alcohol and tea drinking than those of low exposure group (all P values<0.0125). The distributions of age, BMI, family income, cigarette smoking, vitamin intake, history of disease were comparable between high exposure group and low exposure group.2. Associations of EMF exposure with serum lipid parameters were no found after adjustment for potential confounding factors (all P values>0.0125).3. Effects of PF-EMF and RF-EMF on serum lipid levels were observed after adjustment for covariates. Workers with longer employment duration, longer daily occupational exposure time, more mobile phone fee or electric fee per month and exposed to walkie talkie had significantly higher levels of TC, LDL-C or TG (all P values<0.0125). High exposure groups with more mobile phone fee per month had significantly low levels of HDL-C (all P values<0.0125).4. Similar results were also found both in544participants with available data of serum lipids in2010.Part II Effects of EMF Exposure on Blood Cell Parameters1.Demographic characteristics in the Part II (872subjects) were similar to the results of Part I.2. Significant difference of blood cell parameters were no found between high exposure group and low exposure group after adjustment for covariates (all P values>0.003). When P value≦0.003, the power values were low. The chronic effects of EMF on blood cell parameters should be further confirmed in a long term.Conclusion:1.Occupational EMF exposure was associated with the abnormal of serum lipid levels. Significant differences of blood cell parameters were no found between high EMF exposure group and low EMF exposure group.2.Our findings indicate that occupational EMF exposure might increase the risk of dyslipidemia. EMF may disturb the lipid metabolism system in human body. However, the chronic effects of EMF should be further confirmed. The relevant departments of the power plant should pay more attention to monitor the health of workers. Some effective measures are necessary to protect workers from EMF exposure.