Investigating Blood Lead Levels and its Health Effects on Employees of a Petroleum Industry and the Surrounding Residents: A Case Study of Kirkuk City-Iraq.

OBJECTIVE: This study has been aimed to investigate factors associated with elevated blood lead levels (BLLs) across different percentiles in individuals employed in the petroleum industry and residents of Kirkuk city. Additionally, to provide evidence-based approaches to mitigate exposure risks and safeguard vulnerable populations. METHODS: The study involved 357 participants and utilized quantile regression to examine BLL in petroleum industry workers and Kirkuk residents. RESULTS: Median BLLs were higher among workers (17.5 µg/dL) compared to residents in the city (9.9 µg/dL) and suburbs (7.4 µg/dL). Factors such as smoking, outdoor work, and lower education were associated with elevated BLLs, as confirmed by quantile regression. CONCLUSIONS: This study found higher BLLs in petroleum workers compared to Kirkuk residents, associated with smoking, outdoor work, and lower education. The results emphasize the need for targeted interventions and policies to mitigate lead exposure risks in this industrial region.

Testicular histopathology in rats co-exposed to heat and psychological stressors.

Objectives: The present study aimed to investigate the effect of co-exposure to heat and psychological stressors on testicular tissue as one of the major male reproductive organs in rats. Methods: Forty adult male Wistar rats were divided into four groups of 10 animals each. The first group was exposed to heat stress (Temperature Humidity Index: 57.75 ± 3), the second group was exposed to three psychological stressors including strobe light ultrasonic sound, and tilting cage, and the third group was co-exposed to both heat and psychological stress daily. The order of exposure to various psychological stressors was randomized. Following the last day of the 40 -day exposure, the rats were euthanized and their testicular tissues were fixed in Bouin's solution. Moreover, a tissue processor, a microtome as well as hematoxylin, and eosin staining were used for tissue preparation. Results: The co-exposure to psychological and heat stress can cause negative testis histopathological changes including spermatid retention, degeneration of round spermatids and spermatocytes, degeneration and depletion of elongated Spermatid, Sertoli cell status, tubular degeneration/atrophy, Leydig cell atrophy, tubular dilatation, re-tubular dilation, and sclerosis status in a number of rats. Moreover, the histopathological changes were higher in the group exposed to heat stress compared with those exposed to psychological stress. Conclusions: Although exposure to either stressor alone can affect testicular tissue as part of the reproductive system, co-exposure to both stressors may result in an increased risk of adverse effects on testicular tissue.

Assessment of semen quality of taxi drivers exposed to whole body vibration.

Whole body vibration (WBV) is a recognized occupational hazard for many workers such as drivers and operators of heavy and light machinery and exposure to it is accompanied by physical and mental repercussions. Only the limited studies have been done on the effects of vibration exposure on reproductive indices, however vibration exposure has been indicated as being a hazardous agents with the potential of being able to directly affect the reproductive system. Considering the importance of infertility, the present study was conducted with the aim of investigating semen quality among taxi drivers in Tehran and determine the effect of exposure to WBV on sperm parameters. The study population consisted of 70 taxi drivers and 70 office employee who attended infertility clinics for diagnostic purposes in the past year. The participants had to meet the entry criteria of the study while also being willing to recruit. Data was collected in the form of demographic questionnaires and general health questionnaires as well as sperm analysis conducted in an infertility clinic according to standard laboratory guidelines. The 8-hour time-weighted average (TWA) exposure to of WBV in automobile was measured as per ISO 2631-1. The TWA exposure to WBV among the taxi drivers and office employees were 0.697 ± 0.13 m/s2 and 0.068 ± 0.09 m/s2 respectively (P < 0.05). A statistically significant difference in total sperm count, progressive motility, non-progressive motility and total motility was observed between the taxi drivers and the office employees (P < 0.05). According to the univariate analysis of variance, exposure to WBV had negative effect on sperm concentration, progressive motility and normal morphology (P > 0.05); moreover exposure to WBV resulted in the larger effect size (B) on sperm parameters than the demographic variables (P > 0.05). Being taxi drivers increase the chance of the decreased semen quality (P > 0.05). It is difficult to draw definitive conclusions regarding the effects of WBV while intervening factors exist, such as psychological stressors, quality of sleep, background issues as well as environmental factors such as chemical pollutants (heavy metals) or ergonomic factors (body posture and working while sitting down).

Effect of anthropometric and demographic factors on musculoskeletal disorders in nurses' aides.

BACKGROUND: Nurses' aides usually face various stressors, making them prone to musculoskeletal disorders (MSDs). OBJECTIVE: This study evaluates the effect of ergonomic and anthropometric indices, postural risk, and demographic variables on MSDs in nurses' aides. METHODS: Demographic variables, anthropometric dimensions, postural risk level (RL), and related percentiles of 75 nurses' aides were examined using Quick Exposure Check (QEC) software, caliper, and body map questionnaire. Pearson correlation coefficient, univariate and multivariate tests were used to analyze the data. RESULTS: The results showed that the RL of QEC in both groups of males and females was 73.67±22.34 (RL = 4) and 65.34±18.38 (RL = 3), respectively. The level of MSDs in the lumbar, thigh, and leg areas was higher than in other areas. Also, increasing age and work experience, and BMI were significantly associated with increasing disorders in the hands, wrists, and shoulders, respectively (P < 0.05). The results showed that an increase in some anthropometric indices such as body height, buttock, knee, popliteal height, abdomen depth, standing grip access limit, sitting grip access limit increased disorders in the hands and wrists. Also, MSDs were predicted in different areas of the nurses' aides' bodies using regression models, which was significant in the hands, wrists, elbows, legs, and shoulders (P < 0.05). CONCLUSIONS: The results showed that there was a significant difference between male and female nurses in most aspects of anthropometry and the risk level of QEC. Therefore, it is necessary to pay attention to anthropometric dimensions, and demographic diversity to design tools and workstations.

Development and validation of assessment tool of knowledge, attitude, and practice of outdoor workers regarding heat stress.

BACKGROUND: Improving the level of knowledge, attitude and practices of workers exposed to heat stress using a suitable tool can be a cheap and effective method. This requires the consideration of personal, environmental and social factors, which, the PRECEDE model is highly applicable for. Thus, the aim of the present study is the development of a tool assessment for measuring the knowledge, attitude and practices of workers in outdoor occupations regarding heat stress exposure using the PRECEDE model. METHODS: In the present study, a tool was designed and constructed using the PRECEDE model by analyzing the relevant literature and expert opinion. The face validity of the tool was determined based on the opinion of ten experts with experience in the field of occupational weather conditions. The content validity of the tool was determined using the Content Validity Ratio (CVR) and the Content Validity Index (CVI). Cronbach's alpha reliability coefficient was used to determine the reliability of the tool's internal consistency. SPSS version 23 was used for statistical analysis. RESULTS: A PRECEDE based questionnaire was designed with a total of 55 questions consisting of predisposing factors (28 questions for knowledge and 14 questions for attitude), enabling factors (5 questions), reinforcing factors (3 questions) and preventive behaviors (5 questions). The Content Validity Index (CVI) of all questions was above 0.79. The Content Validity Ratio (CVR) of all questions was above 0.62 (Lawshe method). The Cronbach's alpha reliability coefficient of all PRECEDE domains were above the 0.7 acceptable value. Based on the results obtained, all 55 questions were approved and thus the content validity and reliability of this tool was deemed acceptable. CONCLUSION: Considering the reliability and validity of this tool, its application is recommended in all health and safety inspections within various industries for measuring the heat stress knowledge, attitude and practices of workers engaged in outdoor occupations and also for presenting suitable solutions or preventive measures.

The Influence of Vitamin E and Omega-3 Fatty Acids on Reproductive Health Indices Among Male Workers Exposed to Electromagnetic Fields.

The present study aims to investigate the effects of using the supplementation of vitamin E and Omega 3 fatty acids on reproductive indices among workers in an automobile parts manufacturing plant. The effect of exposure to electromagnetic fields on certain sex hormones and sperm parameters will also be assessed. The participants were deployed into four groups as per the double-blind block randomization method. Semen parameters and sex hormones of the participants were analyzed before and after 3-month consumption of supplements. The level of workers' exposure to low-frequency magnetic and electrical fields was measured through the recommendation of National Institute for Occupational Safety and Health. Univariate analysis of variance indicated that exposure to electric fields had a statistically significant effect on sperm count, morphology, and motility. The simultaneous consumption of vitamin E + Omega 3 had a statistically significant effect on sperm morphology and motility.

Feasibility study on the application of electrospun nanofiber webs for the air sampling of crystalline silica.

The aim of the present study was to first fabricate an electrospun PVC nanofiber web and then assess its applicability in sampling and measuring the concentration of airborne crystalline silica by comparing analysis results with a commercial PVC membrane filter under different ranges of airborne silica concentration. A filtration performance comparison was also made between an electrospun PVC web with nano-sized fibers and a commercial PVC membrane filter. Overall, the measured concentration of silica by the electrospun webs was 1.022 times higher than that of the commercial PVC filter in all studied ranges of silica concentration and the nanofiber media had higher filtration efficiency and lower pressure drop compared to the PVC membrane filter. This can be considered to be due to the lower fiber diameter and greater porosity (obtained from the 2D SEM image) of the electrospun nanofiber webs. This makes them suited for air pollutant sampling and determining its airborne concentration.

Comparison of mice' sperm parameters exposed to some hazardous physical agents.

The present study was aimed to compare the effects of exposure to noise, vibration, lighting, and microwave on male mice' sperm parameters. The mice were randomly assigned to five groups of eight, which comprised of the unexposed group and exposure groups including the lighting (1000 lux), noise (100 dB(A)), vibration (acceleration of 1.2 m/s2) and microwave (power density of 5 watts). The exposure groups were subjected to the four agents for 8 hours a day, 5 days a week during a 2-week period. Semen analysis were done according to World Health Organization guidelines. The highest significant mean difference in sperm count (-1.35×106/mL) had being observed between the microwave group and the control one (P=0.001). The highest difference in immotile percent (25.88 %) had being observed between the noise group and the control one (P=0.001). The highest difference in normal morphology (-27.06 %) observed between the lighting exposure group and the control group (P=0.001). The four agents can cause changes in different sperm parameters, however for definite conclusion; more laboratory and field studies are required. In total, exposure to microwave has had the greatest effect on sperm count and exposure to light has had the greatest effect on normal morphology and non-progressive motility. Moreover, exposure to noise has had the greatest effect on progressive motility and immotile percent, respectively.

Relationship between occupational exposure to whole-body vibration and noise with sex hormone levels: An empirical assessment in an automobile parts manufacturing plant.

The present study investigated the relationship between occupational exposure to noise and whole-body vibration (WBV) with the levels of sex hormones in an automobile parts manufacturing plant. The level of workers' exposure (n = 162) to each of the mentioned stressors was measured through standard methods, and the time-weighted average of exposure was calculated for each person. In order to determine serum sex hormones (free testosterone, luteinizing hormone, and follicle-stimulating hormone), blood samples were taken from all participants after 8-10 h of fasting between 7 and 9 am and then the blood samples were analyzed by an enzyme-linked immunosorbent assay method. In general, regarding testosterone as the main male sex hormone, only 49% of the participants were in the normal range. In a total of three sections, the lowest mean testosterone levels were observed in the third exposure group (WBV > 1.93 m/s2; noise >92.69 dB) of the studied stressor; however, only the difference in testosterone levels between the three different groups of exposure to noise was statistically significant (p = 0.001). The relationship between demographic variables and levels of noise and WBV exposure with sex hormones was not linear and only the relationship between noise exposure and testosterone levels was statistically significant (R = -0.201, p = 0.013). According to the results of logistic regression, the WBV had the greatest effect on testosterone levels. However, according to the results of the correlation test, only the relationship between noise exposure and testosterone levels was statistically significant.

The combined effect of industrial noise type, level and frequency characteristics on hand motor skills: A lab trial study.

BACKGROUND: The study aimed to assess the interactive effects of industrial noise type, level and frequency characteristics on hand motor skills using the Minnesota Manual Dexterity Test and the Hand Tool Dexterity Test. METHODS: A total of ten nonsmoking male volunteers with normal hearing and vision were selected for this study. The study followed a full 3×3×2 factorial design. Independent variables were noise type (steady, intermittent and fluctuating), noise level (75, 85 and 95 dBA) and frequency characteristics ("roar" <2000 Hz and "hiss" >2000 Hz). RESULTS: For Minnesota Manual Dexterity Test, the lowest speed is related to steady hiss noise at 75 dBA and the highest speed is related to fluctuating roar noise at 95 dBA. The speed is being significantly affected by the frequency characteristic (P = 0.041) and noise type (P = 0.025). The effect of hiss noise on speed is greater than roar noise (P = 0.038). There is a significant difference (P = 0.035) between continuous noise and fluctuating noise. For the Hand Tool Dexterity Test, the lowest speed is related to fluctuating hiss noise at 95 dBA and the highest speed is related to steady roar noise at 95 dBA. The speed is being significantly affected by the frequency characteristic (P = 0.002), noise type (P = 0.0001) and noise level (P = 0.005). The effect of hiss noise on response variable to be greater than roar noise (P = 0.008). There is a significant difference (P = 0.0001) between steady noise and the two other types of noise, and also there is a significant difference between 75 dBA and 85 dBA level (P = 0.003). CONCLUSIONS: The results showed that on hand motor skills, speed response was influenced by three characteristics: the type of noise, frequency characteristics and noise level. Also, the effect of the hiss noise was more than the roar noise.

Assessment of sexual hormones in foundry workers exposed to heat stress and electromagnetic fields.

The presence of hazardous agents in workplaces has raised concerns regarding their possible impacts on male reproductive system. The present study investigated the individual and combined effects of exposure to heat stress and electromagnetic fields with low-frequency characteristics on the levels of sex hormones in two foundry sections (Aluminum and Cast Iron) of an automobile parts manufacturing plant. The level of workers' exposure (n = 110) to each of the mentioned stressors, was measured through standard methods and for each person and the time-weighted average (TWA) of exposure was calculated. The participants of each sections were classified into separate exposure groups based on the 33rd and 66th percentile of the level of to heat stress and electromagnetic fields exposure. In order to determine serum sex hormones, blood samples were taken from all participants between 7-9 am and then the blood samples were analyzed by ELISA method. In total of two sections, the lowest mean testosterone levels was observed in the third exposure group of the electromagnetic fields (magnetic field>1.40 µT; electric field >0.42 V/m), however, the mean difference in testosterone levels between the three different groups of exposure wasn't statistically significant (P > 0.05). According to the results of Logistic Regression, the electric field had the greatest effect on testosterone levels as the main male hormone. Drawing a definitive conclusion regarding the effects of each harmful physical hazards is difficult due to the existence of psychological stressors and other environmental stressors such as chemical pollution, ergonomic hazards and other physical stressors.

Inside-tube solid-phase microextraction as an interlink between solid-phase microextraction and needle device for n-hexane evaluation in air and urine headspace.

Monitoring the trace amount of chemicals in various samples remains a challenge. This study was conducted to develop a new solid-phase microextraction (SPME) system (inside-tube SPME) for trace analysis of n-hexane in air and urine matrix. The inside-tube SPME system was prepared based on the phase separation technique. A mixture of carbon aerogel and polystyrene was loaded inside the needle using methanol as the anti-solvent. The air matrix of n-hexane was prepared in a Tedlar bag, and n-hexane vapor was sampled at a flow rate of 0.1 L/min. Urine samples spiked with n-hexane were used to simulate the sampling method. The limit of detection using the inside-tube SPME was 0.0003 µg/sample with 2.5 mg of adsorbent, whereas that using the packed needle was 0.004 µg/sample with 5 mg of carbon aerogel. For n-hexane analysis, the day-to-day and within-day coefficient variation were lower than 1.37%, with recoveries over 98.41% achieved. The inside-tube SPME is an inter-link device between two sample preparation methods, namely, a needle trap device and an SPME system. The result of this study suggested the use of the inside-tube SPME containing carbon aerogel (adsorbent) as a simple and fast method with low cost for n-hexane evaluation.

Relationship between heat stress exposure and some immunological parameters among foundry workers.

Occupational exposure to heat stress may lead to changes in blood cell count. The objective of this retrospective descriptive-analytical field study is to investigate the relationship between heat stress exposure and some immunological parameters among foundry workers. This study was carried out on 55 subjects of which, 35 were working in a foundry unit (exposed group) and 20 were working in a computer numerical control (CNC) machining unit (control group). The measurement method consisted of taking 10 cc of the subjects' blood between 10 am and 2 pm and then performing the automated blood cell counting and enzyme-linked immunosorbent assay (ELISA) on the sample. Environmental parameters such as noise levels, lighting, and the wet-bulb globe temperature (WBGT) index were measured at the subjects' workstations. All measurements were made in the first half of the month of July. The mean WBGT index was 22.5 ± 2.16 °C for the control group and 32.97 ± 3.22 °C for the exposed group. The laboratory test results show a significant decrease in white blood cell count and lymphocyte levels and a significant increase in neutrophil levels and neutrophil to lymphocyte ratio in exposed group compared with control ones (P < 0.05). IgM levels decrease under heat stress, but we do not observe significant differences between IgG and IgA levels between two groups. A significant negative correlation was observed between white blood cell count, lymphocyte levels, and IgM concentration with WBGT index and significant positive correlation was observed between neutrophil and neutrophil to lymphocyte ratio with WBGT index. No significant correlation was observed between sound pressure levels and light intensity with studied immunological parameters. In conclusion, under heat stress conditions, leukocytes levels and immunoglobulin concentration may reduce and it may weaken and suppress the human immune system.

The Relationship between Exposure to Lead-Containing Welding Fumes and the Levels of Reproductive Hormones.

Background: Inhalation of lead oxide fumes may cause lead poisoning. Lead has been proven to have harmful effects on different organs. This study aimed to investigate the relationship between the concentration of lead fumes and the levels of reproductive hormones among exposed welders. Methods: A total number of 165 individuals of a construction industry of water pipelines, including 85 welders as the exposure group and 80 administrative staff as the non-exposure group were selected for study. The National Institute for Occupational Safety and Health (NIOSH) 7300 method was used for the purpose of sampling and analysis of lead fumes. Likewise, the NIOSH 8003 method was employed to determine the blood lead level. The level of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone were measured by Chemiluminescence immunoassay(CLIA) test. Data analyses were done by SPSS ver.21 using descriptive statistics, Student>s t-test and Spearman>s correlation test. Results: The average concentration of lead fumes in the breathing zone and blood were 0.57 ± 0.12 mg/m3 and 460.28 ± 93.65 µg/L, correspondingly, which both were significantly higher than threshold limit values (TLV) and biological exposure index (BEI) recommended by American Conference of Governmental Industrial Hygienists (ACGIH)(P < 0.05). The mean levels of LH and FSH were higher in the exposed group than those in the control group (P < 0.05), however, the mean levels of testosterone were lower in the exposed group compared to non-exposed ones (P < 0.05). A strong correlation was found between the concentration of lead fumes and the blood lead levels (r = 0.82; P = 0.003). Blood lead levels were inversely related to the testosterone levels and directly related to LH (r = 0.72; P = 0.004) and FSH (r = 0.78; P = 0.001) levels. Conclusions: Occupational exposure to metal fumes containing lead among welders may alter the level of sexual hormones and potentially harm the reproductive system.

Evaluation of operational parameters role on the emission of fumes.

Electric arc welding is a routine operation in the construction of metallic structures, but the fumes generated during the welding process can threaten the health of welders. Fumes are undesirable products of the majority of welding operations and may have various detrimental effects on health. The purpose of this study was to investigate the effect of operational parameters of the shielded metal arc welding (SMAW) process on the emission of fumes. A dust monitor was used to measure the number and mass concentration of fumes generated by SMAW. Measurements were made at the distances of 23 cm (hood inlet) and 41 cm (welder's breathing zone) from the weld point, with different values assigned to three operational parameters, namely current intensity, travel speed, and heat input (HI). Number concentration (NC) decreased with the increase in particle size. The highest mass concentrations (MC) were observed for MC1 (0.35-0.5 µm) and MC8 (Larger than 6.5 µm). For reducing exposures to fumes, welders are recommended to use the lowest voltage and amperage and the highest travel speed to the extent that does not compromise in the quality of welds. For assessment of exposure to airborne particles in industrial workplaces and specially in welding operations, it is thought that taking, solely, mass concentration in to consideration and lack of attention to number concentration would not be able to reflect accurate assessment of the adverse effects of particles on the body organs.

Application of Universal Thermal Climate Index (UTCI) for assessment of occupational heat stress in open-pit mines.

The purpose of this article is to examine the applicability of Universal Thermal Climate Index (UTCI) index as an innovative index for evaluating of occupational heat stress in outdoor environments. 175 workers of 12 open-pit mines in Tehran, Iran were selected for this research study. First, the environmental variables such as air temperature, wet-bulb temperature, globe temperature, relative humidity and air flow rate were measured; then UTCI, wet-bulb globe temperature (WBGT) and heat stress index (HSI) indices were calculated. Simultaneously, physiological parameters including heart rate, oral temperature, tympanic temperature and skin temperature of workers were measured. UTCI and WBGT are positively significantly correlated with all environmental parameters (p<0.03), except for air velocity (r<-0.39; p>0.05). Moreover, a strong significant relationship was found between UTCI and WBGT (r=0.95; p<0.001). The significant positive correlations exist between physiological parameters including oral temperature, tympanic and skin temperatures and heart rate and both the UTCI and WBGT indices (p<0.029). The highest correlation coefficient has been found between the UTCI and physiological parameters. Due to the low humidity and air velocity (~<1 m/s) in understudied mines, UTCI index appears to be appropriate to assess the occupational heat stress in these outdoor workplaces.

Optimization of electrospinning parameters for polyacrylonitrile-MgO nanofibers applied in air filtration.

UNLABELLED: The present study aimed to optimize the electrospinning parameters for polyacrylonitrile (PAN) nanofibers containing MgO nanoparticle to obtain the appropriate fiber diameter and mat porosity to be applied in air filtration. Optimization of applied voltage, solution concentration, and spinning distance was performed using response surface methodology. In total, 15 trials were done according to the prepared study design. Fiber diameter and porosity were measured using scanning electron microscopic (SEM) image analysis. For air filtration testing, the nanofiber mat was produced based on the suggested optimum conditions for electrospinning. According to the results, the lower solution concentration favored the thinner fiber. The larger diameter gave a higher porosity. At a given spinning distance, there was a negative correlation between fiber diameter and applied voltage. Moreover, there were curvilinear relationships between porosity and both spinning distance and applied voltage at any concentration. It was also concluded that the developed filter medium could be comparable to the high-efficiency particulate air (HEPA) filter in terms of collection efficiency and pressure drop. The empirical models presented in this study can provide an orientation to the subsequent experiments to form uniform and continuous nanofibers for future application in air purification. IMPLICATIONS: High-efficiency filtration is becoming more important, due to decreasing trends air quality. Effective filter media are increasingly needed in industries applying clean-air technologies, and the necessity for developing the high-performance air filters has been more and more felt. Nanofibrous filter media that are mostly fabricated via electrospinning technique have attracted considerable attention in the last decade. The present study aimed to develop the electrospun PAN-containing MgO nanoparticle (using the special functionalities such as absorption and adsorption characteristics, antibacterial functionality, and as a pore-forming agent) filter medium through experimental investigations for application in high-performance air filters.

Assessment of the effect of welding fumes on welders' cognitive failure and health-related quality of life.

INTRODUCTION: This study examined whether cognitive symptoms and health-related quality of life can be affected by welding fume exposure. METHOD: Participants consisted of welders (n = 40) and welder assistants (n = 25) from welding units as the exposed group, and office workers (n = 44) as the non-exposed group. All participants were studied using ambient air monitoring and two types of questionnaires: the Cognitive Failures Questionnaire (CFQ) and the 36-item Short Form Health Survey (SF-36). RESULTS: Welders and welder assistants were exposed to higher concentrations of all airborne metals than office employees, except for aluminum and chromium (p < 0.05). Mean (95% confidence interval) CFQ score was higher in welders (26.42 (12.74)) compared with welder assistants (22.68 (14.37)) and the non-exposed group (21.38 (8.75)), although these differences were not statistically significant. Mean total score of the SF-36 significantly differed among the three groups (p < 0.05) and welders had the lowest score (M (SD) = 54.84 (17.88)). The relationships between total CFQ score and the measured concentration of nickel at peak work rate was significant for welders. CONCLUSION: Cognitive symptoms and health-related quality of life were not related to the measures of welding fume exposure and further research should be performed to find other influencing factors.

The Effect of Occupational Noise Exposure on Blood and Biochemical Parameters: A Case Study of an Insulator Manufacturer in Iran.

INTRODUCTION: Occupational noise is among the most critical occupational hazards, which, in addition to hearing loss, can cause other adverse consequences on an individual's physical and mental health. Long-term exposure to noise can affect blood and biochemical parameters and subsequently lead to increased risk of cardiovascular disease. This study investigated the effect of occupational exposure to noise on blood and biochemical parameters of workers in an insulator manufacturing plant. METHODS: This case-control study was conducted on workers in the production section (49 people as a case group) and the administrative staff (10 people as a control group) in one insulator manufacturing plant from 2010 to 2014. To assess individual exposure of workers to noise, the noise dosimeter model TES-1355 was used. Noise dosimetry testing was done based on the exposure pattern of workers to noise in compliance with the Iranian national standard (the criterion level of 85 dBA and the exchange rate of Q = 3 dBA). Blood parameters such as blood glucose, cholesterol, red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), and hematocrit (Hct) were studied in production workers (case) and administrative staff (control) over five consecutive years. The data were analyzed by software (SPSS-22) using the t-test, Mann-Whitney test, Fisher exact test, and Greenhouse-Geisser test. RESULTS: No significant difference was found among the demographic data of the two groups (p > 0.05). Average of glucose and cholesterol levels in the two groups was statistically significant (p < 0.05) and blood glucose levels in the case group significantly reduced over time and cholesterol increased (p < 0.001). Mean difference of RBC number, WBC number, and serum levels of Hb and Hct was statistically significant between the two groups (p < 0.05). In addition, these hematological parameters increased among workers during these years. CONCLUSION: Occupational exposure to noise may have a significant effect on an individual's blood parameters, which will cause harmful effects on worker health. Therefore, industrialists must take preventive measures in the field of noise control.