|Year : 2017 | Volume
| Issue : 1 | Page : 81-86
Health disorders among workers in a plastic factory in Egypt
Mahmoud E Abu Salem1, Gaafar M Abdel Rasoul1, Omayma A Mahrous1, Olfat M Hendy2, Heba K Allam1, Aziza Saad M Elbadry MSc 1
1 Department of Public Health and Community Medicine, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Clinical Pathology, National Liver Institute, Menoufia University, Menoufia, Egypt
|Date of Submission||14-Aug-2015|
|Date of Acceptance||02-Nov-2015|
|Date of Web Publication||25-Jul-2017|
Aziza Saad M Elbadry
Kafr Manawahla, El-Bajour, Menoufia, 32821
Source of Support: None, Conflict of Interest: None
The aims of this study were to assess the hepatic and hemotologic disorders that may arise among workers in a plastic factory and to assess workplace environment in the same factory.
Occupational exposure to toxic chemicals such as polyvinyl chloride and styrene in plastic manufacturing has deleterious effects on the liver and hematopoietic system after prolonged exposure.
Patients and methods
In a historical cohort study, the exposed participants (n = 180) were recruited from workers in a plastic factory in Queisna industrial zone, Menoufia governorate, Egypt. The unexposed group (n = 60) was selected from workers' relatives who had never worked in the plastic industry. All participants completed a predesigned questionnaire on personal and occupational histories. Complete blood examination, liver function tests, and abdominal ultrasonography were performed for all participants. Environmental studies were also done. Data were collected, tabulated, and statistically analyzed by SPSS statistical package (version 20).
The prevalence of elevated liver enzymes, anemia, and low platelet counts were significantly higher among the exposed than the unexposed participants. Also, mean value of environmental polyvinyl chloride and styrene levels were higher than permissible levels in the grinding department of the factory.
Complete blood count, liver function tests, and abdominal ultrasonography should be included in the periodic medical examination of exposed workers for early detection of hepatic and hematologic disorders.
Keywords: abdominal ultrasonography, liver functions, plastic industry, polyvinyl chloride, styrene
|How to cite this article:|
Abu Salem ME, Abdel Rasoul GM, Mahrous OA, Hendy OM, Allam HK, Elbadry AM. Health disorders among workers in a plastic factory in Egypt. Menoufia Med J 2017;30:81-6
|How to cite this URL:|
Abu Salem ME, Abdel Rasoul GM, Mahrous OA, Hendy OM, Allam HK, Elbadry AM. Health disorders among workers in a plastic factory in Egypt. Menoufia Med J [serial online] 2017 [cited 2020 Jan 26];30:81-6. Available from: http://www.mmj.eg.net/text.asp?2017/30/1/81/211495
| Introduction|| |
Plastic can be defined as a material that contains an essential ingredient of large molecular weight, such as polyvinyl esters, which is solid in its finished state and can be shaped by flow .
Polyvinyl esters, which include polyvinyl acetate and polyvinyl chloride, came into use about the same time as urea–formaldehyde resins. Interestingly enough, vinyl acetate does not seem to have the same toxic and carcinogenic properties as vinyl chloride .
Occupational exposure to vinyl chloride monomer (VCM) may increase the risk of liver cancer and leukemia. When VCM exposure was controlled at work sites, mortality from these cancers returned to background levels .
Previously reported specific risk excesses for liver tumors and liver cirrhosis among autoclave workers and for lung cancer among polyvinyl chloride (PVC) baggers were confirmed in a recent cohort .
The aims of this study were to assess the hepatic and hematologic disorders that may arise among workers in a plastic factory and to assess the workplace environment in the same factory.
| Patients and Methods|| |
This cohort study was conducted from the beginning of September 2013 to the end of October 2014 in a plastic factory in the industrial zone in Queisna city, Menoufia governorate, Egypt.
The respective approvals of the review board and the ethics committee of the Menoufia Faculty of Medicine were obtained before commencing the study.
Workers in this factory work in three 8-h shifts a day for 7 days a week. The total workforce of the factory is 370 patients, which is distributed all over four departments as follows:
- Plastic injection department, 250 workers
- Grinding department, 60 workers
- Maintenance department, 50 workers
- Product distribution department, 10 workers.
Of 370 occupationally exposed workers, 180 participated in this study after excluding nonresponders and applying the exclusion criteria. They were recruited from different departments of the factory including 60 workers from grinding department, 60 from maintenance and final products distribution department, and 60 from plastic injection department. Workers with positive hepatitis viral makers, hypertension, diabetes mellitus (DM), and past history of liver or kidney diseases were excluded from the study.
An age-matched and sex-matched unexposed group of 60 individuals who had never worked in plastic factories were recruited from the workers' relatives. They were also matched for residence, education level, and socioeconomic status.
An interview was done at the workplace in a quiet room during the morning shift 1 h after breakfast. It was done for six workers a day with every setting taking almost 30 min. All participants were volunteers. Written informed consents were signed by all participants before being enrolled into the study and each was asked to do his best.
All enrolled participants were subjected to the following:
- Personal interview: each participant was asked to complete a predesigned questionnaire included questions about age, sex, residence, marital status, educational level, special habits, and socioeconomic status. The participants were also asked for detailed occupational history: their present occupational history (duration of employment, nature of the job, the way of dealing with raw materials and final products, the average hours of work per day, and the number of days worked per week), past occupational history (place, nature, and duration of previous occupations), and any additional jobs; medical history of chest and neurological symptoms; family history: consanguinity, its degree, and any diseases running in families, such as hypertension and DM; and past history of diseases, such as DM, hypertension, cardiovascular disease, hepatic disease, and renal disease or the chronic use of any drugs
- Clinical examination: general clinical examination, including measurement of blood pressure, weight, height, and pulse rate, and thorough abdominal and chest examinations were done for each participant
- Blood sampling: 10 ml of venous blood was withdrawn by sterile syringe through venipuncture of the antecubital vein and divided into two glass tubes: 5 ml of blood was put in the first tube containing potassium EDTA for complete blood count (CBC), and prothrombin time and checked well to prevent blood clotting. The remaining 5 ml of the blood sample was put into empty tube (no anticoagulant) and left to clot and then centrifuged for liver function, serum glutamic oxaloacetic transaminase (SGOT) level, glutamic pyruvic transaminase (SGPT) level, serum total bilirubin level, and serum albumin level tests
- Abdominal ultrasonography: transabdominal ultrasound was done by a well-trained radiologist by a portable machine (SonoScape S6 Portable Ultrasound Machine, Guangzhou Med Equipment Co., Ltd., Guangdong, China) with abdominal linear probe 3.5–5 MHz. Systematic examination was performed of the abdomen starting from the upper-right quadrant followed by pelvic examination with the urinary bladder semifilled and then after evacuation of urine
- Environmental measurements: air samples have been taken at breathing zones of workers. In total, three readings were taken from different departments of the factory, where the mean value was recorded. Samples were measured by portable ambient air analyzer (Miran Sapphire; Tucson, USA).
Data were collected, tabulated, and statistically analyzed using an IBM compatible personal computer with SPSS statistical package (version 20; SPSS Inc., Chicago, Illinois, USA). The following two types of statistics were done:
- Descriptive statistics: for example, number, percent, mean, and SD
- Analytic statistics: Student's t-test, which is a test used for comparison between groups having quantitative variables. χ2-Test was used to study association between two qualitative variables. Fisher's exact test for 2 × 2 tables when the expected cell count of more than 25% of cases was less than 5. Z-Test is a significance test for testing proportions.
Pearson's correlation coefficient test (r test) is a test of significance used to study the correlation between two quantitative variables, whereas Spearman's correlation coefficient test (r test) is a test of significance used to study the correlation between two qualitative variables. Correlation coefficient test (r test) results may be positive correlation or negative correlation. It is used to quantify the strength of the linear relationship between two variables. P value of 0.05 or less was considered statistically significant.
| Results|| |
There was no statistically significant difference between the two groups regarding the sociodemographic characteristics [Table 1].
|Table 1 Distribution of sociodemographic characteristics of the studied groups|
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Heartburn and diarrhea were significantly more prevalent in the exposed group than in the control one (P < 0.05). Bleeding per gums and from orifices and ecchymosis were significantly more prevalent in the exposed group than in the control one (P < 0.05), as shown through the abdominal complaints [Table 2].
There was a highly significant difference between the exposed and control groups (P < 00.1) regarding liver enzymes, hemoglobin concentration, and white blood cells count, with elevated liver enzymes (SGOT and SGPT), low hemoglobin, and leukocytosis in the exposed group [Table 3].
There was a significant difference between workers in the plastic grinding department in comparison with workers in other departments regarding abnormal SGOT, hemoglobin concentration, and platelet count [Table 4].
|Table 4 Comparison of the results of investigation findings for workers in grinding and other departments|
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There was a negative correlation between duration of employment (in years) and hemoglobin and platelets count and positive correlation with liver enzymes SGOT and SGPT among exposed workers, reaching a significant level for SGOT (P < 0.05) when using Pearson's correlation test [Table 5].
|Table 5 Pearson's correlation between duration of employment (years) and liver functions and complete blood count among the exposed group (n=180)|
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The mean environmental PVC and styrene levels at the workplace of the exposed group were higher than permissible levels of the Egyptian environmental law [Table 6] (Law 4 Decree 1095/2011) and threshold limit value of the National Institute of Occupational Safety and Health (NIOSH), and noise level was higher than permissible level of the Egyptian environmental law (the Egyptian Environmental Law 4, 1994) and NIOSH in the grinding department [Figure 1] and [Figure 2].
|Table 6 Environmental measurements at the workplace of the exposed group|
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|Figure 1: Mean values of polyvinyl chloride (PVC) concentration (mg/m3) around work site machines.|
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|Figure 2: Mean values of styrene concentration (mg/m3) around work site machines.|
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| Discussion|| |
In the studied factory, environmental measurements recorded that mean values of environmental PVC and styrene in grinding department were 4.24 ± 1.09 and 320.12 ± 11.93 mg/m 3, respectively, which are higher than the permissible level of the Egyptian Ministry of Trade and Industry in 2011 (Law 4 Decree 1095), which is 3 and 215 mg/m 3, respectively, and threshold limit value of NIOSH (2003) at 2.5 and 215 mg/m 3, respectively ,. Therefore, hepatic disorders found among workers in this factory may be attributed to occupational exposure to these higher levels of PVC and styrene.
In our study, the presence of elevated liver enzymes (SGOT and SGPT), low hemoglobin concentration, high white blood cells, and low platelet counts was significantly higher in the exposed versus the control group.
As PVC was reported to be hazardous to the liver, detection of elevated liver enzymes is not surprising, and the mechanism should be clarified. Previous human and animal studies indicated that glutathione (GSH) depletion may be the causative factor ,.
Glutathione-S-transferases and glutathione play an important role in the metabolism of PVC, of which the electrophilic intermediate metabolites are conjugated with GSH to be detoxified. Thus, GSH depletion caused by hepatitis virus infection may lead to an accumulation of active intermediate metabolites of PVC, which then exacerbate PVC-induced hepatotoxicity ,,.
In our study, exposed workers in the plastic grinding sector have higher incidence of headache, pallor, elevated SGOT level, low hemoglobin concentration, and lower platelet counts in comparison with exposed workers in other departments of the factory.
Workers in the grinding section are more exposed to chemical monomers through inhalation route than workers in other departments . In addition, VCM exposure was high on average and very high during autoclave cleaning compared with VCM air measurements reported in other departments in the plastic industry .
Absence of cases with suspected liver cancer in our study is mostly attributed to short period of exposure to PVC and younger age of our study population.
In western countries, hepatic angiosarcoma accounts for only 2% of hepatic malignancy, and it occurs more frequently in men with a male to female ratio of ∼3:1 to 4:1 and most frequently in the sixth to seventh decades of life . High VCM concentration is essential for liver angiosarcoma occurrence, although the length of exposure is also of concern . Moreover, exposure to VCM should be for at least 10 years with a latency period of 30–40 years to develop hepatic angiosarcoma .
This is further supported by Collins et al. , who examined more than 73 000 death certificates of North American workers employed between 1940 and 2008 and found 13 deaths owing to angiosarcoma of the liver among workers with vinyl chloride exposure. All 13 deaths occurred at a single plant among workers with high vinyl chloride exposure. The mean latency period after first exposure was 36.5 years (range: 24–56 years). No angiosarcoma of the liver deaths occurred among workers with vinyl chloride exposures after 1974, when exposures were reduced .
According to the available knowledge, the strength of our study resides in being the first study to be conducted in Egypt to assess the hepatic and hemovascular disorders in plastic industry.
Inability to include older workers after retirement and to record other health disorders in plastic industry were the main limitations of our study.
From the results obtained in this study, it can be stated that pre-employment and periodic physical examination and investigations should include estimation of the liver function tests and complete blood picture combined with abdominal ultrasonography to pick and exclude affected workers; moreover, health education programs for using personal protective equipments should be conducted and the recommended allowable concentrations of PVC and styrene exposure should be maintained at the workplace.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]