Ambient air pollutants and breast cancer stage in Tehran, Iran.

This study aimed to examine the impacts of single and multiple air pollutants (AP) on the severity of breast cancer (BC). Data of 1148 diagnosed BC cases (2008-2016) were obtained from the Cancer Research Center and private oncologist offices in Tehran, Iran. Ambient PM10, SO2, NO, NO2, NOX, benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, and BTEX data were obtained from previously developed land use regression models. Associations between pollutants and stage of BC were assessed by multinomial logistic regression models. An increase of 10 µg/m3 in ethylbenzene, o-xylene, m-xylene, and 10 ppb of NO corresponded to 10.41 (95% CI 1.32-82.41), 4.07 (1.46-11.33), 2.89 (1.08-7.73) and 1.08 (1.00-1.15) increase in the odds of stage I versus non-invasive BC, respectively. Benzene (OR, odds ratio = 1.16, 95% CI 1.01-1.33) and o-xylene (OR = 1.18, 1.02-1.38) were associated with increased odds of incidence of BC stages III & IV versus non-invasive stages. BC stage I and stage III&IV in women living in low SES areas was associated with significantly higher levels of benzene, ethylbenzene, o-xylene, and m-xylene. The highest multiple-air-pollutants quartile was associated with a higher odds of stage I BC (OR = 3.16) in patients under 50 years old. This study provides evidence that exposure to AP is associated with increased BC stage at diagnosis, especially under premenopause age.

Bridging research-policy gaps: An integrated approach.

It is often difficult for policymakers to make informed decisions without evidence-based support, resulting in potentially ineffective policies. The purpose of this article is to advocate for collaboration and communication between researchers and policymakers to enhance evidence-based policymaking. The workshop hosted by the International Society of Environmental Epidemiology-Eastern Mediterranean Chapter further explores the challenges of connecting researchers and policymakers. The article highlights the gap between researchers and policymakers, attributed to different visions and objectives, time constraints, and communication issues. To strengthen the research-policy interface, strategies such as enhanced communication skills and early involvement of policymakers in research are suggested. The article proposes an integrated model combining the Collaborative Knowledge Model and the policy entrepreneurship mindset, emphasizing the co-creation of knowledge and evidence-based policy solutions. The use of this model can lead to the development of evidence-based policies that effectively address societal needs.

Application of Multiple Occupational Health Risk Assessment Models for Crystalline Silica Dust among Stone Carvers.

OBJECTIVE: Silica is the most abundant substance on the Earth's crust and is a proven carcinogen. The aim of this study was to measure the occupational exposure of stone carvers to crystalline silica and to evaluate the health risks.  Methods: This descriptive and analytical cross-sectional study was performed on 79 stone carvers. Inhalation air sampling was performed by the NIOSH7500 method and the amount of silica was determined by X-ray diffraction (XRD). Semi-quantitative and quantitative risk assessments were performed using the methods of the Singapore Department and the US Environmental Protection Agency (EPA), respectively. Mortality due to silicosis and lung cancer were estimated using the Manettej and Rice models. Data were analyzed using SPSS23 software. RESULTS: The mean exposure to total inhalable dust and crystalline silica among the stone carvers was 1.44 and 0.5 mg/m3, respectively. Exposure to total dust and silica was significantly higher than the occupational standard (P <0.0001). Stone carvers' exposure to silica was at very high-risk level, and the carcinogenicity of silica considering two cancer slopes was 7.40 × 10-6 and 3.12 × 10-7 and the risk of non-carcinogenicity was unacceptable. CONCLUSION: The mortality rate due to silicosis was between 3 and 12 people per thousand, and due to lung cancer was 150.24 people per thousand. Based on the results of risk assessment, serious control measures should be implemented in order to reduce workers' exposure to silica.

The experiences of Red Crescent relief workers during the COVID-19 pandemic in Iran: a qualitative phenomenological study.

BACKGROUND: The daily increase of infected individuals and mortalities related to COVID-19 in Iran increased public fear and anxiety and affected the job performance of many health workers, including the Iranian Red Crescent Society, as one of the organizations responding to COVID-19. METHODS: This study aimed to explore the experiences of Red Crescent rescuers, using a qualitative method with an interpretative phenomenological analysis (IPA), and by conducting semi-structured and in-depth interviews with Red Crescent relief workers from Mashhad in September 2020. Participants were selected by purposive sampling. RESULTS: Rescuers in the Red Crescent Society, had gained different experiences during the COVID-19 pandemic. The experiences were categorized into four main themes. These main themes were: (1) Psychological disorders, (2) Organizational support (3) Mis-management (both structural and human factors), and (4) Opportunities. CONCLUSION: The COVID-19 epidemic did create unique opportunities to understand the pitfalls of the Red Crescent aid services. Red Crescent rescue workers suffered from psychological symptoms, and mismanagement was also present. Psychological support and organizational improvements should be implemented.

Geographic variation in urinary tract and genital cancers in Iran: a hypothesis involving exposure to solar radiation.

OBJECTIVE: Sunlight and vitamin D intake are considered as essential elements for human health. Insufficient intake of this vitamin is one of the causes of various cancers and some other diseases. The aim of this study was to investigate the relation between bladder, prostate, cervical and ovarian cancers with solar ultraviolet exposure in Iran. In this ecological study, data from 30 provinces were studied and analyzed by correlation and linear regression tests in SPSS software version 22. Physical activity, gender, human development index, lung cancer and altitude were adjusted at population level. RESULTS: The incidence of bladder cancer in both sexes was inversely related to ultraviolet radiation, but it was significant only in men. Unlike bladder cancer, the incidence of cervical cancer showed a positive relation with ultraviolet radiation. No relation was found between the incidence of prostate and ovarian cancers with ultraviolet radiation. Among the adjusting variables, the incidence of lung cancer (surrogate for smoking) in women had the highest coefficient in the linear regression model.

Factors related to earthquake preparedness of households based on social-cognitive theory constructs: A systematic review.

Background: Earthquakes cause many casualties worldwide. Taking preventive measures and improving community preparedness is critical to reducing earthquake damage. The social cognitive theory explains how individual and environmental factors cause behavior. This review was conducted to identify the social cognitive theory structures, in research on the preparedness of households against earthquakes. Materials and methods: This systematic review was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search was conducted from January 1, 2000, to October 30, 2021 in Web of Science, Scopus, PubMed, and Google Scholar. Studies were selected based on inclusion and exclusion criteria. The initial search yielded 9,225 articles, and finally, 18 articles were selected. Articles were assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist. Results: Eighteen articles about disaster preparedness behaviors based on the socio-cognitive constructs were identified and reviewed. The essential constructs used in the reviewed studies included self-efficacy, collective efficacy, knowledge, outcome expectations, social support, and normative beliefs. Conclusion: By identifying the dominant structures that have been used in studies related to the preparedness of households against earthquakes, researchers can implement appropriate and more cost-effective interventions by focusing on improving suitable structures.

Efficacy of frankincense-based herbal product in urinary incontinence: A randomized, double-blind, placebo- and active-controlled clinical trial.

Urinary incontinence is a silent epidemic that has a serious impact on a person's quality of life (QOL). This study aimed to evaluate the efficacy of frankincense-based herbal product (FHP) in urinary incontinence compared with placebo and solifenacin. In this randomized, double-blind clinical trial, 120 postmenopausal women with mixed urinary incontinence were randomized to one of the three groups of FHP, placebo, and standard treatment (solifenacin). Frequency, amount of leakage, and score of urinary incontinence as well as the QOL were measured at the end of the second and fourth weeks and 2 weeks after the interruption of the treatment. The ICIQ-UI SF and I-QOL questionnaires were used for the measurements. Mean frequency of urinary incontinence and amount of leakage significantly decreased in the FHP and solifenacin groups in the fourth week compared to the placebo group. In addition, 2 weeks after treatment completion, the effects of the FHP were significant compared to the solifenacin group. Due to the effect of FHP on improving the QOL and also the prolonged effect of this drug, the use of FHP in urinary incontinence, as a complementary treatment could be suggested.

Temporal Pattern and Age-Period-Cohort Analysis of Breast Cancer Incidence in Iranian Women (2009-2017).

BACKGROUND: Breast cancer accounted for 28.1% of all female cancers in 2020 in Iran. This study was conducted to evaluate the time trend of breast cancer incidence and to identify the changes of breast cancer incidence in age, period, and birth cohorts in Iran, in the 2009-2017 timeframe. METHODS: Annual cancer statistics for female breast cancer were obtained from the Iranian National Population-based Cancer Registry (INPCR) database from 2009 to 2017. The age-period-cohort (APC) analysis was used to evaluate the time trend of breast cancer incidence in age, period and birth cohorts between 2009 and 2017. R package (Epi) was used to analyze data. Results were considered statistically significant at P<0.05. RESULTS: The age effect showed an increased incidence of breast cancer until the age of 45, and after this age the speed of increase was slower until 65 years. There was an increased diagnosis in 2015-2017 (period effect) for many age groups, especially in the 70- and over 80-year-old group. CONCLUSION: Our findings indicated that breast cancer incidence peaks in the age of 45 in Iranian women, which is a decade earlier compared to the Western world. The period effect in 2015-2017 can be explained by the fact that in 2014, the former Iranian pathology-based cancer registry was upgraded to a population-based cancer registry, which resulted in improved coverage of cancer registry and case finding.

Evaluation of Date Extract on Nerve Conduction Velocity in Male Rats.

Introduction: Neuropathy is a condition in which the Peripheral Nervous System (PNS) is disordered. Studying the effects of antioxidants on the performance improvement of this system is vital. This study aimed to investigate the effects of date extract on Nerve Conduction Velocity (NCV), Distal Motor Latency (DML), and wave height of the sciatic nerve in male rats. Methods: This laboratory study used 24 male Wistar rats weighing 250-300 g, divided into the test and control groups. The test group received 10% date extract daily, at 4 mL/kg of body weight, for three weeks. In the beginning, nerve Conduction Velocity (NCV), Distal Motor Latency (DML), and wave height of the sciatic nerve were examined in all animals and reexamined for NCV three weeks later. P-values lower than 0.05 were considered significant. Results: Sciatic NCV and wave height were significantly increased; however, compared to the control group, DML of the knee significantly declined in the test group. Conclusion: The compositions of date extract accelerate electrical signal transmission. Highlights: Irreparable damages to the Peripheral Nervous System (PNS) are major problems in societies.Different therapeutic methods have been adopted for peripheral nerve repair.According to FAO, the production and use of dates are rising.Dates are used in traditional medicine for curing hoarseness, paralysis, backache, and rheumatic pains. Plain Language Summary: Dates are highly important in our nutrition. There have been studies on the positive antioxidative effects of date extract in preventing diabetic neuropathy. Dates are used in traditional medicine for curing hoarseness, paralysis, backache, and rheumatic pains, among others. The importance of dates is derived from their rich compositions of carbohydrates, salts and minerals, dietary fiber, vitamins, fatty acids, amino acids, and proteins. Different therapeutic methods have been adopted for PNS, still, 50% of these damages become permanent and cause disability. Date palms are in the palm family native to Iran, and found in relatively tropical regions.Dates are used in traditional medicine for curing hoarseness, paralysis, backache, and rheumatic pains, among others. In short, the compositions of date extract accelerate electrical signal transmission.

The viewpoints of residents of Kerman, Iran regarding the challenges and barriers of preparing households against earthquakes: A theory-guided qualitative content analysis.

Introduction: Earthquakes cause a lot of damage and casualties. For various reasons, most households are not prepared for earthquakes. This study aims to identify the challenges and barriers to households' preparedness against earthquakes from the viewpoint of Kerman residents. Methods: This qualitative-directed content analysis study was conducted from December 2021 to May 2022 in the city of Kerman in southeast Iran. Data was collected by purposive sampling through in-depth and semi-structured individual face-to-face interviews with 48 households. Results: After multiple rounds of analyzing and summarizing the data based on the social-cognitive theory and taking into consideration similarities and differences, five main categories and 19 subcategories created based on the results of data analysis and including (1) Challenges related to cognitive factors (2) Challenges related to behavioral factors (3) Challenges related to the physical environment (4) Challenges related to the social environment and (5) Challenges related to financial factors. Conclusion: Although the participants listed many challenges and barriers in different fields, in order to overcome the barriers and challenges of preparing households for an earthquake, the support of the authorities and the cooperation of the residents are necessary.

Organochlorine and organophosphorus pesticides may induce brain cancer through oxidative stress.

In this study, oxidative stress was investigated as the possible mechanism of action of organochlorine pesticides (OCPs) and organophosphorus pesticides (OPPs) in primary brain tumors (PBT). The levels of seven OCP residues and enzymatic antioxidant biomarkers including erythrocyte acetylcholinesterase (AChE), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and paraoxonase-1 (PON-1) along with non-enzymatic oxidative biomarkers including malondialdehyde (MDA), protein carbonyl (PC), total antioxidant capacity (TAC), and nitric oxide (NO) were measured in blood samples of 73 patients with PBT and 104 healthy controls. A significant association was found between farming activities and PBT (55% of patients were engaged in farming activities while 45% had no farming experience). The mean levels of ß-HCH, γ-HCH, 2,4 DDE, 4,4 DDE, 4,4 DDT, MDA, PC, NO, SOD, CAT, and GPx were significantly higher in PBT patients, whereas the levels of TAC, PON-1, and AChE were significantly lower in these patients. Regression analysis showed that PBT was correlated with ß-HCH, γ-HCH, 2,4 DDE, 4,4 DDE, and 4,4 DDT. Based on these results, it can be concluded that OCPs and OPPs may play a role in PBT development through the formation of reactive oxygen species (ROS) and promoting oxidative stress.

Carcinogenic risk assessment and changes in Spirometric indices in casting and welding workers exposed to Metal fumes.

INTRODUCTION: The aim of this study was to investigate exposure to dust, and metal fumes, changes in pulmonary function indices among industrial workers to estimate the carcinogenic and non-carcinogenic risk of exposure to occupational metal fume.

Methods: This cross-sectional study was performed on 98 workers exposed to metal fumes. Air sampling was performed according to the NIOSH 0500 method and was analyzed by gravimetry and metal levels were analyzed by atomic absorption spectrometry. Spirometric results for 2010-2016 were collected. Carcinogenic and non-carcinogenic risk assessments were performed according to the US Environmental Protection Agency guidelines. Data were analyzed by SPSS 20 software. RESULTS: The mean occupational exposure of the subjects to workplace dust and iron fumes was 15.95 ± 6.65 mg/m3 and 13.18 ± 3.06 mg/m3 respectively. During these 6 years, the FVC (P=0.04), PEFR (P=0.04), and FEV1 (P=0.03) indices decreased significantly among welders, but there was no significant difference between FEV1/ FVC indexes. Also, the mean of FEV1 and PEFR decreased significantly amongst casting workers, but FVC and FEV1/ FVC had no significant difference. Multivariate regression showed that in both jobs, BMI and work history were related to pulmonary function indices. The mean total excess ifetime carcinogenic risk (ELCR) of hexavalent chromium in the study population was 0.708 per 1000 people and the mean non-carcinogenic risk of hexavalent chromium was HQ = 19.62. CONCLUSIONS: The results showed that exposure to metal fumes in casting and welding jobs reduces pulmonary function indices. Although the average occupational exposure to hexavalent chromium is lower than the recommended limit and the risk of carcinogenesis is within an acceptable range, the risk of non-carcinogenic effects among workers is significant Therefore, it is important to prevent this problem, by adequate ventilation and using respiratory masks.

A Review of Studies Using Air Q Software for Prediction of Air Pollution Health Effects in Iran.

PURPOSE OF REVIEW: Exposure to air pollutants may lead to various health effects and is a major public health issue. Concerns about these effects exist in both developed and developing countries. The Air Q software was developed to estimate the health impacts of air pollution based on reported levels of air pollutants in real world studies. In Iran several studies have been conducted to estimate human morbidity and mortality based on this software. We conducted this review to summarize articles which have predicted the effects of air pollution on human health in Iran using Air Q. We conducted a systematic search for relevant studies published until 24 April 2021 in Web of Science, PubMed, Scopus, and SID (Scientific Information Database which includes articles in Farsi language). We applied no time or language restrictions. RECENT FINDINGS: A total of 44 studies out of 525 identified articles met our inclusion criteria. The main air pollutants under investigation were particulate matter (PM), NO2, O3, and SO2. Most studies were conducted in metropolitan areas, such as Ahvaz (9 studies), Tehran (9 studies), and Shiraz (7 studies). In all studies, the levels of most air pollutants were higher than the 2005 WHO guideline levels and were predicted to be related to considerable health effects. However, it was not possible to aggregate the results and report the total number of casualties during these years, because studies were done in different cities with fluctuating levels of multiple pollutants and in different years and time frames. This systematic review showed that air pollution remains at unacceptably high levels resulting in substantial detrimental health effects in various Iranian cities. Using clean renewable energies, increasing human capital, and increasing green spaces and vegetation can help improve air pollution and decrease human casualties in Iran.

Multiple air pollutants exposure and leukaemia incidence in Tehran, Iran from 2010 to 2016: a retrospective cohort study.

OBJECTIVE: Leukaemia is one of the most common cancers and may be associated with exposure to environmental carcinogens, especially outdoor air pollutants. The objective of this study was to investigate the association of ambient air pollution and leukaemia in Tehran, Iran. DESIGN: In this retrospective cohort study, data about the residential district of leukaemia cases diagnosed from 2010 to 2016 were inquired from the Ministry of Health cancer database. Data from a previous study were used to determine long-term average exposure to different air pollutants in 22 districts of Tehran. Latent profile analysis (LPA) was used to classify pollutants in two exposure profiles. The association between air pollutants and leukaemia incidence was analysed by negative binomial regression. SETTING: Twenty-two districts of Tehran megacity. PARTICIPANTS: Patients with leukaemia. OUTCOME MEASURES: The outcome variables were incidence rate ratios (IRR) of acute myeloid and lymphoid leukaemia across the districts of Tehran. RESULTS: The districts with higher concentrations for all pollutants were near the city centre. The IRR was positive but non-significant for most of the air pollutants. However, annual mean NOx was directly and significantly associated with total leukaemia incidence in the fully adjusted model (IRR (95% CI): 1.03 (1.003 to 1.06) per 10 ppb increase). Based on LPA, districts with a higher multiple air-pollutants profile were also associated with higher leukaemia incidence (IRR (95% CI): 1.003 (0.99 to 1.007) per 1 ppb increase). CONCLUSIONS: Our study shows that districts with higher air pollution (nitrogen oxides and multipollutants) have higher incidence rates of leukaemia in Tehran, Iran. This study warrants conducting further research with individual human data and better control of confounding.

Occupational exposure to pesticides in farmworkers and the oxidative markers.

Organophosphate (OPPs) and organochlorine pesticides (OCPs) are the two predominant forms of pesticides extensively used all around the world and are being reconsidered as environmental pollutants. The current study sought to assess the role of socioeconomic factors on the level of pesticides residues and the oxidative effects of exposure to OPPs and OCPs among the farmworkers of southeast Iran. In this cross-sectional study, 192 farmworkers and 74 non-farmworkers (controls) were involved. Gas chromatography (GC) was performed to measure the serum levels of organochlorine chemicals (2,4-DDT, 4,4-DDT, 2,4-DDE, 4,4-DDE, α-HCH, ß-HCH, and γ-HCH). Furthermore, acetylcholinesterase (AChE) activity, arylesterase activity of paraoxonase-1 (PON-1), and several oxidative stress (OS) markers were assessed. In addition, the impact of several parameters such as home to farm distance, education level, ventilation status, and personal protective equipment (PPE) on pesticide levels was analyzed. The levels of OCPs in the farmworkers were significantly higher than the control subjects. In addition, AChE activity, arylesterase activity of PON-1, and total antioxidant capacity in farmworkers were significantly less, and MDA levels were higher than the controls. Education level was associated with farmworkers' protective behavior. The current findings suggested that some phased out OCPs can still be measured in human samples in the southeast of Iran. Furthermore, the current study demonstrated that exposure to OCPs and OPPs was accompanied by adverse consequences regarding OS parameters and subsequent health problems. In addition, the findings of the present study suggest that improving farmworkers' education might be associated with reduced exposure to pesticides and less adverse health effects.

The effect of climate change on malaria transmission in the southeast of Iran.

Malaria is a vector-borne disease, likely to be affected by climate change. In this study, general circulation model (GCM)-based scenarios were used for projecting future climate patterns and malaria incidence by artificial neural networks (ANN) in Zahedan district, Iran. Daily malaria incidence data of Zahedan district from 2000 to 2019 were inquired. The gamma test was used to select the appropriate combination of parameters for nonlinear modeling. The future climate pattern projections were obtained from HadGEM2-ES. The output was downscaled using LARS-WG stochastic weather generator under two Representative Concentration Pathway (RCP2.6 and RCP8.5) scenarios. The effect of climate change on malaria transmission for 2021-2060 was simulated by ANN. The designed model indicated that the future climate in Zahedan district will be warmer, more humid, and with more precipitation. Assessment of the potential impact of climate change on the incidence of malaria by ANN showed the number of malaria cases in Zahedan under both scenarios (RCP2.6 and RCP 8.5). It should be noted that due to the lack of daily malaria data before 2013, monthly data from 2000 were used only for initial analysis; and in preprocessing and simulation analyses, the daily malaria data from 2013 to 2019 were used. Therefore, if proper interventions are not implemented, malaria will continue to be a health issue in this region.

Universal Thermal Climate Index (UTCI) and adverse pregnancy outcomes in Ahvaz, Iran.

BACKGROUND: Climate change may jeopardize the health of mothers and their offspring. There are few studies on the association between increasing temperature and pregnancy outcomes. The aim of this study was to investigate the relation between Universal Thermal Climate Index (UTCI) and adverse pregnancy outcomes including stillbirth, low birth weight (LBW), preterm labor (PTL), spontaneous abortion (SA), preeclampsia and hypertension in Ahvaz, Iran. METHODS: Distributed Lag Non-linear Models (DLNM) combined with quasi-Poisson regression were used to research the effect of UTCI on adverse pregnancy outcomes. The effect of time trend, air pollutants (NO2, SO2 and PM10), and weekdays were adjusted. RESULTS: The results showed that the low values of UTCI index (11.6 °C, in lags 0-6, 0-13) caused significant increase in the risk of preterm labor. However, hot thermal stress (high UTCI) significantly increased the risk of stillbirth in lag 0-13. We did not observe any significant relation between UTCI and other pregnancy outcomes in this study. CONCLUSIONS: It seems like both hot and cold weathers can be associated with adverse pregnancy outcomes.

Scientists have found that climate change has adverse effects on human health. Because pregnant women are one of the most vulnerable groups, these negative impacts may affect their fetuses, which make up the next generation. In this study, we examined the effect of temperature on some pregnancy outcomes, including low birth weight, preterm labor, spontaneous abortion, preeclampsia and gestational hypertension in Ahvaz city, which is one of the hottest cities in the world.One way to assess temperature impact on humans is by using temperature indicators. In this study we used the Universal Thermal Climate Index (UTCI) for this purpose. The data at different time intervals were collected and evaluated with specific models.Our results showed that low values of UTCI, which is equivalent to cold weather, significantly increase the risk of preterm labor. But, high levels of UTCI, which means hot weather, significantly increase the risk of stillbirth.In conclusion; both hot and cold weather can be associated with adverse pregnancy outcomes in Ahvaz city. Therefore, pregnant women should protect themselves from exposure to hot and cold weather.

Evaluation of oxidative stress and biochemical biomarkers, and psychological parameters in cement plant workers.

The cement industry is one of the main world industries with exposure to a wide range of hazardous chemical and physical occupational agents that may increase free radicals and lead to disease. The aim of this study was to evaluate oxidative stress, biochemical markers, and psychological parameters among cement plant workers. In this cross-sectional study, 40 workers exposed to cement and 40 office employees were selected as the exposed and non-exposed groups, respectively. Exposure to cement dust, silica, and noise were, respectively, assessed using the NIOSH 0600, NIOSH 7601, and noise dosimetry methods. Oxidative stress biomarkers including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and biochemical parameters were measured in the serum of all participants. Depression, anxiety, and stress were assessed by the Depression Anxiety Stress Scales (DASS-21) questionnaire. The results demonstrated that the level of MDA as a marker of oxidative stress was significantly higher in the exposed group. The level of antioxidant enzymes including SOD and CAT were also significantly higher in the exposed group. The level of TAC was lower in the exposed group, but the difference was not statistically significant. The levels of alkaline phosphatase (ALP), aspartate transaminase (AST), and the scores of depression and stress were also significantly higher in the exposed group. According to our results, noise, cement dust, and silica exposure were associated with oxidative stress, and this may be one of the mechanisms in which they adversely affect liver function and mental health.

Evaluating the effect of heat stress on cognitive performance of petrochemical workers: A field study.

INTRODUCTION: Heat stress disrupts blood hormones and reduces workers' cognitive performance. To further shed light on the dysfunction of heat stress, the present study aimed to evaluate its effect on cognitive performance of petrochemical workers. MATERIALS AND METHODS: This descriptive-analytical cross-sectional study was conducted in 2020 in one of the Iranian petrochemical companies. Participants were divided into 2 case groups and 1 control group. They worked 12 h and their shift entialed one week working day and one week working night. According to the ISO 7243 standard, the heat stress index of employees was measured at the beginning, in the middle and at the end of the shift separately. Continuous Performance Test (CPT) and N-back cognitive performance tests were performed at the beginning, in the middle and at the end of the shift to determine the level of cognitive performance. The data were analyzed using SPSS software version 20 and the significance level was set at 0.05. RESULTS: Comparison of the results in the continuous performance test showed significant differences between the three groups with regard to the omission error and response time at the end of the shift. Moreover, according to the working memory test, participants reaction time during the shift significantly increased. Besides, average correct responses significantly reduced during the shift. Finally, the heat stress throughout the shift had a significant effect on the commission error and the response time of individuals. CONCLUSION: Heat stress affects people's cognitive performance in such a way that it can decrease their cognitive performance by increasing the commission error and response time and reducing the average correct response of site operators, generally reducing the cognitive performance of people at the end of the shift.