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.

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.

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.

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.

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.

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.

Prevalence of Sexual Dysfunction and Related Risk Factors in Men with Multiple Sclerosis in Iran: A Multicenter Study.

INTRODUCTION: Sexual dysfunction (SD) is a common complaint in patients with multiple sclerosis (MS). The aim of this study was to assess the prevalence of SD and its related risk factors in men with MS in Iran. METHODS: In this cross-sectional study, 320 men who had been diagnosed with MS according to the McDonald revised criteria were recruited from January to June 2019, from the north, south, east, west, and central parts of Iran. Patients were assessed using the Male Sexual Health Questionnaire (MSHQ), International Index of Erectile Function (IIEF), The Multiple Sclerosis Intimacy and Sexuality Questionnaire-(MSISQ 19), Sexual Quality of Life-Men (SQOL-M), and Standard General Health Questionnaire (GHQ). RESULTS: Sexual dysfunction, defined as total IIEF score ≤ 45 was present in 114 patients (35.6%). The results of univariate logistic regression showed that there were significant direct relations between age (OR 1.050, 95% CI 1.02-1.08), Expanded Disability Status Scale (EDSS) (OR 1.45, 95% CI 1.24-1.7), duration of MS (OR 1.005, 95% CI 1.002-1.009), MSISQ-19 (OR 1.103, 95% CI 1.078-1.128), GHQ (OR 1.04, 95% CI 1.03-1.06), SQOL-M (OR 0.930, 95% CI 0.914-0.947), smoking (OR 1.941, 95% CI 1.181-3.188), non-MS chronic disease (OR 1.91, 95% CI 1.20-3.04), having a main sexual partner (OR 2.56, 95% CI 1.32-4.94), and significant inverse relations between exercise (OR 0.584, 95% CI 0.364-0.936) and regular sexual activity (OR 0.241, 95% CI 0.15-0.40), with the prevalence of SD. The results of multiple logistic regression indicated that the age, MSISQ-19, and SQOL-M were the only independent predictive factors for SD in these patients. CONCLUSION: The prevalence of SD in men with MS in Iran is relatively high. These patients should be screened, diagnosed, and treated for SD and influencing factors.

Multiple air pollutant exposure and lung cancer in Tehran, Iran.

Lung cancer is the most rapidly increasing malignancy worldwide with an estimated 2.1 million cancer cases in the latest, 2018 World Health Organization (WHO) report. The objective of this study was to investigate the association of air pollution and lung cancer, in Tehran, Iran. Residential area information of the latest registered lung cancer cases that were diagnosed between 2014 and 2016 (N = 1,850) were inquired from the population-based cancer registry of Tehran. Long-term average exposure to PM10, SO2, NO, NO2, NOX, benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene (BTEX), and BTEX in 22 districts of Tehran were estimated using land use regression models. Latent profile analysis (LPA) was used to generate multi-pollutant exposure profiles. Negative binomial regression analysis was used to examine the association between air pollutants and lung cancer incidence. The districts with higher concentrations for all pollutants were mostly in downtown and around the railway station. Districts with a higher concentration for NOx (IRR = 1.05, for each 10 unit increase in air pollutant), benzene (IRR = 3.86), toluene (IRR = 1.50), ethylbenzene (IRR = 5.16), p-xylene (IRR = 9.41), o-xylene (IRR = 7.93), m-xylene (IRR = 2.63) and TBTEX (IRR = 1.21) were significantly associated with higher lung cancer incidence. Districts with a higher multiple air-pollution profile were also associated with more lung cancer incidence (IRR = 1.01). Our study shows a positive association between air pollution and lung cancer incidence. This association was stronger for, respectively, p-xylene, o-xylene, ethylbenzene, benzene, m-xylene and toluene.

Exposure to cadmium and head and neck cancers: a meta-analysis of observational studies.

Cadmium (Cd) is a widespread environmental pollutant. A number of observational studies have reported that Cd might be a cause of nasopharyngeal (NPC), pharyngeal (PC), or laryngeal cancers (LC). In this study evidence about the relation of Cd and NPC, PC, and LC has been summarized. A literature review was conducted until 20 June 2020 in PubMed, Ovid, Scopus, Web of Science and Google scholar databases to investigate the epidemiologic evidence for the relation between cadmium exposure and cancers of the nasopharynx, pharynx, and larynx. Ten articles were selected after careful screening of retrieved studies. All of these studies obtained a Newcastle-Ottawa Scale (NOS) quality score from 6 to 8. Due to high heterogeneity, in all analyses, random effect was used. The pooled results showed that cadmium levels in NPC (standard mean difference (SMD=0.55; 95% CI=0.20, 0.89; p=0.002) and PC (SMD=9.79; 95% CI=0.62, 18.96; p=0.036) patients/tissues were significantly higher than their controls. But cadmium levels were not significantly different between LC cases/tissues and their controls. (SMD=-0.05; 95% CI=-0.99, 0.89; p=0.921). Exposure to cadmium is likely to cause nasopharyngeal and pharyngeal cancer.

The effect of chronic exposure to flour dust on pulmonary functions.

Purpose. This study aimed to examine the effect of chronic exposure to flour dust on the pulmonary symptoms and pulmonary indices of mill workers. Methods. The cohort study was conducted on 67 mill workers and 53 controls from 2014 to 2016. Demographic information was collected through interviews and pulmonary indices; flour dust exposure was measured by spirometry, and NIOSH 0500 and NIOSH 0600 methods. Results. The incidences of pulmonary symptoms, including cough, sputum, dyspnea, wheezing and bronchitis, were significantly more in the case group than the control group. At the beginning of the study, there was no significant difference between the case and control groups regarding the pulmonary indices of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), peak expiratory flow and FEV1/FVC; however, after 2 years of exposure to flour dust, the pulmonary indices significantly decreased in the case group and showed a restrictive pattern. Based on the linear regression model, the most important predictor variables of FVC and FEV1 were age, body mass index, smoking and level of exposure to respirable flour dust. Conclusions: There is a strong correlation between chronic exposure to flour dust and the incidence of pulmonary complications and reduced pulmonary functions.

Oxidative stress associated with long term occupational exposure to extremely low frequency electric and magnetic fields.

BACKGROUND: Occupational exposure to extremely low frequency electromagnetic fields (ELF-EMFs) may have harmful effects on biologic systems and has raised many concerns in the last decades. OBJECTIVE: The aim of this study was to determine the effects of exposure to extremely low frequency electric and magnetic fields on lipid peroxidation and antioxidant enzyme activities. METHODS: This study was conducted on 115 power plant workers as the exposed group and 145 office workers as the non-exposed group. The levels of Malondialdehyde (MDA), superoxide dismutase (SOD), Catalase (Cat), and total antioxidant capacity (TAC) were measured in the serum of all subjects. Exposure to ELF-EMFs was measured based on spot measurements and the IEEE Std C95.3.1 standard. RESULTS: The levels of MDA, SOD, and Cat in the exposed group were significantly higher than in the non-exposed group. However, the level of TAC was not significantly different between the exposed (2.45±1.02) and non-exposed (2.21±1.07) groups. The levels of MDA and SOD were higher among workers with higher exposure to electric fields than workers with low exposure. All oxidative stress indicators increased with increased exposure to magnetic fields, except TAC. CONCLUSIONS: The antioxidant system imbalance among power plant workers may be related to long term occupational exposure to electromagnetic fields.

The Effects of Antioxidant Vitamins on Proinflammatory Cytokines and Some Biochemical Parameters of Power Plant Workers: A Double-Blind Randomized Controlled Clinical Trial.

Some epidemiological studies have suggested that exposure to extremely low-frequency magnetic fields (ELF-MFs) can affect the immune system. This study aimed to investigate the effects of antioxidant vitamin consumption on proinflammatory cytokines and biochemical parameters changes. In this randomized, controlled double-blinded trial study, power plant workers exposed to ELF-MFs were enrolled based on inclusion criteria. Ninety-one eligible subjects were randomly divided into four groups: the first group (400 units of vitamin E/day), second group (1,000 mg of vitamin C/day), third group (400 units of vitamin E and 1,000 mg of vitamin C/day), and control group. The intervention was conducted for 3 months. Proinflammatory cytokines interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor-α (TNF-α), and biochemical parameters (fasting blood sugar, total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol [HDL-c], total protein, and albumin) were measured among the participants' serums, before and after the intervention. The mean level of IL-6 in all vitamin-receiving groups, the mean level of IL-1ß in vitamin C and E&C groups, and the mean level of TNF-α in the vitamin C group, decreased significantly after intervention. The arithmetic means of the effect sizes for IL-1ß, IL-6, and TNF-α were 0.71, 0.57, and 0.2, respectively. The level of HDL-c in the vitamin E and vitamin E&C groups and the level of triglyceride in the vitamin C group significantly increased after the intervention. Taking antioxidant vitamins can prevent an increase of proinflammatory cytokines induced by prolonged exposure to ELF-MFs. Bioelectromagnetics. 2021;42:18-26. © 2020 Bioelectromagnetics Society.

Does Adenotonsillectomy alter Symptoms of Attention Deficit Hyperactivity Disorder in Children?

INTRODUCTION: Attention deficit hyperactivity disorder (ADHD) has the highest prevalence among psychiatric disorders in children. The present study investigated the effect of adenotonsillectomy on the symptoms of ADHD in a 6-month follow-up. MATERIALS AND METHODS: This cross-sectional study was performed on 100 patients referred for respiratory problems during sleep due to adenotonsillar hypertrophy (ATH). The patients' parents were asked to complete the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition checklist as a standard benchmark for ADHD before, 2 weeks, and 6 months after the surgery. The data were analyzed by SPSS software (version 20) through paired t-tests and McNemar's test. RESULTS: The age averages of male and female children were 7.15 and 8.4 years, respectively. The frequency of ADHD in the studied population was 30%, which is much higher than the prevalence of this disorder in the normal population. In the second week after the surgery, the mean score of ADHD decreased from 4.97±2.97 (attention deficit [AD]) and 6.77±1.61 (hyperactivity disorder [HD]) before the surgery to 3.86±2.25 (AD) and 4.28±2.02 (HD) 2 weeks after the surgery (P=0.001). After a 6-month follow-up, these figures further decreased (AD=2.34±2.32; HD=1.97±2.44; P<0.001). CONCLUSION: Adenotonsillectomy had a significant effect on the improvement of ADHD symptoms. There is a necessity for checking patients with ADHD for ATH, especially in case of sleep disorders, sleep apnea, snoring, or mouth breathing.

The effect of noise and dust exposure on oxidative stress among livestock and poultry feed industry workers.

INTRODUCTION: Simultaneous exposure to noise and dust may have detrimental health effects. This study was conducted to determine the effect of exposure to noise and dust on oxidative stress. METHODS: In this cross-sectional study, 82 employees of two livestock and poultry feed factories in Golestan Province, Iran, were selected as the exposed group and 82 office workers were selected as the control group. Occupational noise and dust exposure were measured using a dosimeter, sampling pump, and vinyl chloride filter. Oxidative stress was determined by measuring the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in blood samples. T-tests, one-way analysis of variance, and multivariate linear regression were used to analyze the data. RESULTS: The levels of MDA and SOD in the exposed group were significantly higher and lower than the control group (p < 0.001), respectively. The results showed the subgroup with both over the threshold dust and noise exposure had the highest MDA levels. The SOD level among those exposed to noise more than the recommended level, in the subgroup with more dust exposure, was significantly less than the subgroup with low noise exposure (p = 0.017). CONCLUSION: Noise and dust exposure probably increase the level of oxidative stress by increasing the level of lipid peroxidation (MDA) and reducing the level of antioxidant enzymes (SOD).

Changes in Spirometry Indices and Lung Cancer Mortality Risk Estimation in Concrete Workers Exposed io Crystalline Silica.

The health of workers in the concrete and cement industries can be at risk due to occupational exposure to silica dust. The purpose of this study was to evaluate the changes of pulmonary parameters and risk of mortality from lung cancer in concrete workers exposed to crystalline silica. This cross-sectional study was performed on 72 male workers exposed to silica at a concrete manufacturing plant in Neyshabur, Iran. Respiratory zone air sampling was performed using the standard NIOSH7602 method using individual sampling pumps and membrane filters. Then, the amount of silica in the samples was determined using the Fourier Transform Infrared technique. The risk of death from lung cancer was determined using Rice et al.'s model. Respiratory indices were measured using a spirometer. Data were analyzed by the SPSS 20 software. Occupational exposure to silica was 0.025 mg/m3 and mortality was estimated to be 7-94 per thousand. All spirometry indices significantly decreased during these 4 years of exposure to silica dust. The respiratory pattern of 22% of the exposed workers was obstructive and this prevalence was significantly higher than the control group. The results showed that although the average occupational exposure to silica in these concrete workers was below the recommended threshold of national and international organizations, their risk of death was significantly higher; and workers' lung indices had significantly decreased over four years. Therefore, appropriate measures should be taken to reduce silica exposure among these workers.

Is opium use associated with an increased risk of lung cancer? A case-control study.

BACKGROUND: In recent years, lung cancer (LC) incidence has increased in Iran. The use of opium and its derivatives (O&D) has increased as well. This study aimed to investigate the association between the use of O&D and LC incidence. METHODS: In this case-control study conducted in Kerman, Iran; 140 patients with lung cancer and 280 healthy controls matched by age, sex, and place of residence were included. Data, including O&D use, cigarette smoking, alcohol use, and diet, were collected using a structured questionnaire. The relation between the use of O&D and LC was evaluated using conditional logistic regression adjusted for tobacco smoking, education, daily intake of fruit, vegetables, red meat, and hydrogenated fats. RESULTS: Opium ever-use was associated with an increased risk of LC (Adjusted Odds Ratio (AOR) =5.95, 95% CI: 1.87-18.92). Participants were divided into low and high use groups based on the median of opium use in the control group. A significant dose-response relation was observed between the amount of daily O&D use and LC; and the relation was stronger in high users (AOR low users = 3.81% CI: 1.13-12.77 and OR high users = 9.36, 95% CI: 2.05-42.72). Also, LC was higher among participants starting the use of O&D at younger ages (≤ 41 years old vs never users AOR = 8.64, 95% CI: 1.90-39.18) compared to those who started at an older age (> 41 years old vs never users, AOR = 4.71, 95% CI: 1.38-16.08). The association between opium, and lung cancer among non-smokers was OR: 6.50 (95% CI: 2.89 to 14.64). CONCLUSION: The results of this study show that opium use is probably a dose related risk factor for lung cancer.

Neuropsychological effects of long-term occupational exposure to mercury among chloralkali workers.

BACKGROUND: Mercury is one of the most well-known toxic metals for humans. Chloralkali workers are exposed to mercury vapours extensively, which may be associated with neurotoxicity. OBJECTIVE: The aim of this study was to determine the associations between mercury concentration in blood and air samples, and mercury's neuropsychological effects among chloralkali workers. METHODS: This study was conducted on 50 chloralkali workers as the exposed group and 50 non-industrial office workers as the unexposed group. All subjects were assessed using the Hamilton Depression Rating Scale, Piper Chronic Fatigue Scale and Essential Tremor Rating Scale. Mercury concentration was measured in blood and air samples using cold vapour atomic absorption spectrometry. RESULTS: There was significantly more severe fatigue, depression and tremor in the exposed group compared with the unexposed group. The mean concentration of blood mercury in the exposed group was 22.59±12.5µgL-1 which was significantly higher than the unexposed group (1.28±1.05µg L-1). Based on multiple linear regression, shift work, smoking, fatigue, depression and tremor were predictor variables for blood mercury concentration. CONCLUSIONS: This study indicated that this sample of chloralkali workers suffered from neuropsychological problems such as fatigue, depression and tremor, which is probably related to mercury exposure.

Investigating the effects of exposure to extremely low frequency electromagnetic fields on job burnout syndrome and the severity of depression; the role of oxidative stress.

OBJECTIVES: This study was designed to investigate the possible effect of exposure to extremely low frequency electromagnetic fields (ELF-EMFs) on occupational burnout syndrome and the severity of depression experienced among thermal power plant workers and the role of oxidative stress. METHODS: In this cross-sectional study, 115 power plant workers and 124 administrative personnel of a hospital were enrolled as exposed and unexposed groups, respectively, based on inclusion and exclusion criteria. Levels of oxidative stress biomarkers, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (Cat), and total antioxidant capacity were measured in serum samples. Exposure to electric and magnetic fields was measured using the IEEE Std C95.3.1 standard at each workstation. The burnout syndrome and the severity of depression were assessed using the Maslach Burnout and Beck Depression Inventory. RESULTS: The levels of MDA and SOD were significantly lower in the exposed group than the unexposed group. The exposed group reported a higher prevalence of burnout syndrome and higher depression severity. Multiple linear regression showed that work experience, MDA level, and levels of exposure to magnetic fields are the most important predictor variables for burnout syndrome and severity of depression. In addition, a decrease in the level of Cat was significantly associated with increased burnout syndrome. CONCLUSION: The thermal power plant workers exposed to ELF-EMFs are at risk of burnout syndrome and depression. These effects may be caused directly by exposure to magnetic fields or indirectly due to increased oxidative stress indices.