Occupational Hazards Research Articles

Development of Livestock-Associated Methicillin-Resistant Staphylococcus aureus (LA-MRSA) Loads in Pigs and Pig Stables During the Fattening Period

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is widespread in European pig production and poses an occupational hazard to farm workers and their household members. Farm workers are exposed to LA-MRSA through direct contact with pigs and airborne transmission, enabling bacteria to be carried home in the nose or on the skin. Consequently, it is important to consider LA-MRSA in a one-health context, studying human exposure by examining LA-MRSA levels in pigs, air, and dust in the farm environment. In this investigation, LA-MRSA levels were quantified in nasal swab samples from the pigs, air samples, and dust at three different time points in a farm rearing pigs from approx. 30 kg until slaughter. Sampling was repeated across seven batches of pigs, resulting in the analysis of 504 nasal swab samples, alongside air and dust samples. LA-MRSA was cultured and quantified on MRSA2 agar plates. Findings revealed significant batch-to-batch variation and a significant 94.1% decrease in LA-MRSA levels during the rearing period. Despite this decline, all nasal swab samples tested positive, with the highest level reaching 353,000 cfu in a sample. Among the 42 air samples, LA-MRSA levels were low to moderate, with a maximum of 568 and an average of 63 cfu/m3. In the 28 dust samples collected during the second and third sampling periods, LA-MRSA counts were high, reaching up to 37,272 cfu/g, with an average of 17,185 cfu/g. The results suggest that while LA-MRSA levels in pigs decrease with age, reaching low levels before slaughter, the bacterium remains highly abundant in dust, posing an occupational hazard to farm workers.

EPID-22. MUTATIONAL SIGNATURE ASSOCIATED WITH HALOALKANE EXPOSURE ENRICHED IN FIREFIGHTERS IN THE ADULT GLIOMA STUDY

Abstract Using data from The Cancer Genome Atlas (TCGA) and Glioma Longitudinal Analysis (GLASS), we identified specific environmentally related mutational signatures in glioma including a signature associated with haloalkane exposure (SBS42) from the Catalogue of Somatic Mutational Signatures (COSMIC). Haloalkanes are widely used commercially including in flame retardants and fire extinguishants and are an intriguing finding given an observed increased glioma risk in firefighters. To validate our findings, we use new study participants with data on occupation (not available in either TCGA/GLASS) from the University of California, San Francisco Adult Glioma Study (AGS) to compare mutational signatures in tumors from 17 persons with glioma and documented occupational exposure to firefighting with those of 18 matched glioma patients without history of firefighting. Using whole exome sequencing, we identified environmental exposure signatures in tumor tissue from firefighters as well as in non-firefighters who had other relevant occupational exposure (e.g. auto/truck mechanic work). In these data, glioma is largely associated with aging and mutational signatures relating to endogenous mutational processes that correlate with age, such as spontaneous or enzymatic deamination of 5-methylcytosine. However, some gliomas have detectable signatures associated with exogenous mutational processes, such as SBS42 haloalkanes. Thus, we confirm detection of haloalkane signatures in persons likely highly exposed, i.e. long-term firefighters. Identifying exogenous mutational processes in cancers are important as they may inform public health intervention strategy to reduce mutagenesis and prevent cancer inception. Identifying occupational correlates with SBS42, associated with occupational exposure to haloalkanes, will pinpoint occupational hazards that may be avoidable. This is especially important for glioma and other cancers where exogenous mutagenesis is not well established.

Prevalence and Association of Components of Metabolic Syndrome and Uric Acid among Commercial Drivers in South-West Nigeria

Abstract Introduction: Metabolic syndrome (MetS) is a complex cluster of metabolic abnormalities characterized by central obesity, dyslipidemia, hypertension, and impaired glucose metabolism. Emerging evidence suggests a potential link between uric acid levels and MetS, and commercial drivers are exposed to unique occupational hazards that may predispose them to MetS and hyperuricemia. Objectives: The objective of this study was to determine the prevalence of MetS and its relationship with serum uric acid among commercial drivers in Ado-Ekiti, Nigeria. Materials and Methods: A cross-sectional study was conducted among commercial drivers in Ado-Ekiti. Relevant information was obtained with a questionnaire, and anthropometry and blood pressure were measured. Fasting plasma glucose and lipid profiles were determined by the standard protocol. MetS was determined with the harmonized criteria. Bivariate correlation and Chi-square were used to determine the relationship between serum uric acid and MetS and its components. Results: There were 106 participants with a median age (interquartile range) of 50 (11) years, with no difference between those with or without MetS. More than 70% of the participants drank alcohol and 75 (70.8%) participants had hyperuricemia. There was no significant correlation between serum uric acid and components of MetS. The prevalence of MetS among all the participants was 21.7% (23/106), with no difference among men with normal uric acid (25.8%) and those with elevated uric acid (20.0%), P = 0.509. Similarly, there was no statistical difference in the prevalence of the components of MetS between the two groups. Conclusions: The prevalence of MetS among the commercial drivers was high, with no difference among men with or without hyperuricemia. Given the importance of this group of people, a system-level public health approach should be adopted to promote a healthy lifestyle to save the lives of the populace.

Disposal of SARS-CoV-2 corpses: experiences of environmental health officers

BackgroundThough the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is no more of a public health emergency, the experiences from burying SARS-CoV-2 infectious dead bodies may remain with the workers. For Environmental Health Officers (EHOs), dealing with decedents during the SARS-CoV-2 outbreak may arouse strong feelings of pity, horror, repulsion, disgust, and anger at the tragedy. Therefore, this study aims to explore the experiences of EHOs in disposing off of confirmed or suspected SARS-CoV-2 fatalities in Ghana.MethodsUsing an 18-item interview guide, we gathered data from 27 EHOs from three regions of Ghana. We followed the steps in Descriptive Phenomenology in conducting the data analysis.Resultsi. EHOs were confronted with several occupational health and safety (OHS) hazards like physical and chemical injuries, threat of harm, and psychological harm, ii. The officers also faced severe shortage of personal protective equipment (PPE). Unfortunately, they were not provided with any form of psychological support during the period.ConclusionThe SARS-CoV-2 outbreak in Ghana exposed major fault lines in the health and safety/disaster and emergency preparedness of EHOs towards the burial of infectious disease dead bodies. Clearly, the disposal exercise failed to uphold the Sustainable Development Goals (SDGs) 4.4, 8.3, and 8.5, which advocate for the promotion of decent jobs for all.RecommendationGhana’s Ministries of Health, Local Government, and Sanitation and Water Resources need to attach Clinical Psychologists and security personnel to the disposal teams in future exercises to provide psychological support and security to the team. Though studies on the disposal of infectious bodies in Africa exist, very little is known about the experiences of EHOs in the disposal of SARS-CoV-2 dead bodies during the outbreak.

Relationship Between Occupational Exposure to Noise and Vibrations and Vertigo: A Prospective Case-Control Study

Background/Objectives: It is known that balance disorders involve occupational hazards. However, the inverse relationship (between certain occupations and an increased incidence of vertigo or dizziness) has been scarcely studied. The objective of this work was to analyze the occupation of a group of patients with vertigo compared to the economically active general population and to evaluate the prevalence of occupational noise and/or vibration exposure in both groups. Methods: A prospective cross-sectional, observational, case-control study was carried out, including 393 patients (193: Meniere’s disease; 63: vestibular migraine; 21: vestibular neuritis; 116: BPPV) (244 women and 149 men). These patients were compared to a control group from the general population obtained from 6th EWCS-Spain (2015). Possible differences regarding sex, age, occupation, exposure to noise, and exposure to mechanical vibrations were analyzed. Results: Differences in the distribution of occupations between patients with vertigo and the general population were observed (Chi-square, p = 4.065 × e−20). Patients with vertigo were significantly more exposed to noise (Fisher’s exact test, p = 2.97 × e−10; OR = 2.595, CI95% (1.916;3.515)) and vibrations (Fisher’s exact test, p = 6.23 × e−10; OR = 2.722, CI95% (1.963;3.775)) than the control group. These differences were observed both between men and women. Conclusions: A relationship between occupational exposure to noise and/or vibrations and the presence of vertigo was observed. Protective and preventive measures could help prevent the occurrence of some diseases involving vertigo.

Dairy Chain Safety in the Context of Antibiotic Residues—Current Status of Confirmatory Liquid Chromatography Methods: A Review

With ever-developing analytical capabilities, the protection of the dairy chain from contamination by residues of veterinary drugs is improving. Legislative requirements are an inherent part of this process. Of antibiotics in dairy farming, representatives of the beta-lactams, tetracyclines, sulfonamides, (fluoro)quinolones, aminoglycosides, or polypeptide antibiotics are the most widely used. Due to the typically low levels of antibiotic residues in milk, mass spectrometry is the most commonly used detection technique. However, the interference of the sample matrix is one of its main limiting factors, and therefore, it needs to be eliminated. In the first step, the lipid fraction is removed and proteins are precipitated, followed by solid-phase or liquid–liquid extraction. The current trends include the reduction in the consumption of organic solvents (to reduce occupational hazards and burden to the environment) and automation, eliminating the influence of human error and optimizing the workflow. These trends lead to the development of new microextraction and automated techniques as well as the use of new sorbents and/or (green) solvents of natural origin. To capture the latest developments in the field and the relatively recent aforementioned trends, this review focuses on papers investigating antimicrobial residues in milk that were published between 2015 and 2024, providing an overview of emerging techniques applicable to antibiotic residue detection in milk samples.

Understanding the Risk Factors, Burden, and Interventions for Chronic Respiratory Diseases in Low- and Middle-Income Countries: A Scoping Review

ObjectiveThis scoping review aims to identify risk factors for COPD and asthma, examine the burden and intervention measures, and clarify the findings in the context of climate change, with a particular focus on LMICs.MethodsFollowing the PRISMA-ScR guidelines, we conducted a scoping review using PubMed, Embase, and Scopus, focusing on studies published from 2011 to 2024.ResultsOur review included 52 studies that encompassed 244,004 participants. Predominantly conducted in SSA (n = 43, 83%) and Asia (n = 16, 31%), they address indoor and ambient air pollution, occupational hazards, and environmental conditions. Climate change exacerbates risks, varying regionally. SSA faces severe household and occupational exposures, while other LMICs deal with industrial and urban pollution. Stigma, social exclusion and economic burden underscore the necessity for intervention strategies (e.g., educational programs, pulmonary rehabilitation, low-emission cookstoves).ConclusionOur research shows a strong link between air pollution, occupational and environmental exposures, and the prevalence of COPD and asthma in LMICs. It suggests that targeted interventions are effective ways to mitigate these diseases and also highlights the significant impact of climate change on respiratory health.

Safe limits on work hours for the nursing profession: a rapid evidence review

Persistent staffing shortages in health care driven by years of inadequate funding and deficiencies in human resources planning, which overlooked the impacts of population aging, have converged into a crisis in health care settings. An essential consequence of the widespread and growing staffing shortfalls in health care has been increased pressure on nurses to work longer hours. The present rapid review has two major objectives: (1) to systematically review and synthesize evidence considering the health and human consequences of excessive work hours, work-related fatigue and associated occupational health and safety hazards; and, (2) to identify policies and practices that demonstrate efficacy in managing or mitigating the adverse effects of occupational fatigue. Findings show that shifts lasting longer than 12 h elevate the risk of occupational fatigue, leading to several fatigue-based hazards. Despite governmental restrictions on long work hours and occupational fatigue in safety-critical industries such as transport, aviation, and nuclear sectors, health care remains largely unregulated in this regard. Ensuring safe and high-quality care over the long term requires implementing adequate regulatory supports for work hour limits for nurses. These measures not only improve workplace satisfaction but also enhance patient outcomes, ultimately fostering a healthier and more resilient health care system.

Relationship Between Musculoskeletal Disorders on Job Performance

Background: The World Health Organization (WHO) and International Labour Organization (ILO) have identified musculoskeletal disorders (MSDs) as a rising epidemic within the workforce. These injuries account for 33% of all occupational injuries and 40% of medical costs. Objectives: This study aimed to determine the effect of MSDs on the job performance of operating room employees. Methods: This descriptive and analytical study was conducted on 100 participants. Job performance was assessed using the Patterson Job Performance Questionnaire (JPQ), and MSDs were evaluated using the NORDIC Questionnaire. Data were analyzed with SPSS version 16, employing Mann-Whitney, chi-square, and binary logistic regression tests. Results: Among the participants, 43% were women, and 67% were men, with an average age of 27.37 ± 6.45. Sixty-two percent of participants did not have acceptable job performance. Additionally, 83% reported at least one musculoskeletal injury, 64% had at least two injuries, and 62% had three or more injuries across different body parts. The results indicated a significant relationship between job performance and variables such as hip, knee, lower back, upper back injuries, age, gender, literacy level, physical activity, and work experience. However, no significant relationship was found between neck injuries and marital status with job performance (P < 0.05). Conclusions: This study demonstrates that MSDs can negatively impact employee job performance. Given the influence of various occupational factors on performance, it is recommended that future studies simultaneously examine the effects of other occupational hazards.

A descriptive study to assess the knowledge attitude and practice of employees regarding prevention of occupational health hazards in a selected sugar mill of Uttar Pradesh

Background: Approximately 30 to 50% works exposed to occupational health hazard and 120 million workers become victim in 200000 fatalities annually. Aim of the study was to assess the knowledge attitude and practice of employees regarding prevention of occupational health hazards in a selected sugar mill of Uttar Pradesh. Methods: A descriptive survey was done on co-operate sugar mill Baghat. Data has been taken from the co-operate sugar mill employees working on the machine and in field areas. 100 participants had chosen using convenient sampling technique. Structured knowledge questionnaire was developed to assess knowledge, structured checklist to measure practices and Likert scale to assess attitude of employees. Results: 60% employees worked in machinery area and 40% were in field area. 37% have not faced any hazards faced, 26% has faced eye infection, 19% got fracture,18% developed respiratory problems, 17% faced crush injuries, 16% had back problem, 13% have burn injuries and 4% had history of any kind of allergy. 6% of sugar mill employees had good knowledge, 51% sugar mill employees had average and 43% employees had poor knowledge. 15% employees had good practice; 85% employees had poor 90% employees had good attitude; 10% employees had poor attitude regarding occupational health hazard. Conclusions: Lack of knowledge regarding prevention of occupational health hazard put workers on risk of many diseases. Awareness program should be conducted regularly to enhance knowledge of workers and improve their skills.

Factors Related to Dental Ergonomics Practice Among Indonesian Dentists.

Dentists are at greater risk of work-related musculoskeletal disorders (WMSDs) which can be caused by repetitive movements, improper posture and long working hours. If ergonomic principles are applied in the field of dentistry, they help to prevent occupational ergonomic health hazards and provides more comfort to the dentist and patient. To obtain information regarding dental ergonomics practice of dentists in Indonesia and its related factors. A cross-sectional study was conducted using a purposive sampling method via Google Form to 231 dentists in DKI Jakarta, Indonesia from November to December 2022. The questionnaire consisted of 34 items divided into five sections; socio-demographic, job characteristics, knowledge of dental ergonomics, attitude towards dental ergonomics and the practice of dentists regarding dental ergonomics. Bivariate analysis was conducted using Pearson Chi-square Test. 76.2% dentists have poor dental ergonomics practice. There is a significant relationship (p-value < 0.05) between the practice of dental ergonomics and age group, years of practical experience and level of knowledge. Most Indonesian dentists (76.2%) still lack of dental ergonomics practice. Age, duration of work experience and ergonomic dental practice knowledge are significantly correlated.

Alcohol Misuse and Correlates with Mental Health Indicators among Firefighters

Background: Stress and repetitive exposures to potentially traumatizing events are inherent to first-responder professions. Firefighters and other crisis responders are often exposed to incidents in their work environments and are at risk of developing acute or posttraumatic symptomatology, depression, and anxiety, as well as harmful patterns of alcohol consumption. Most prior research and theory suggests that many firefighters use alcohol to cope with past and current stressors, and that increased drinking accompanies ongoing exposures to stressful occupational hazards. Objectives: The primary aim of this research was to examine alcohol consumption and mental health variables associated in the literature with alcohol misuse. Participants included 546 predominantly male career firefighters in the U.S. Using a cross-sectional design, we examined alcohol misuse in the context of self-reported depression, generalized anxiety, PTSD, and suicidal ideation using previously validated measures. Results: Based on the AUDIT’s recommended cut score of 8, 38.8% of our sample reported drinking at hazardous levels. Hazardous alcohol use was also significantly associated with several mental health indicators with correlations ranging from .28 to .34. Regression analyses revealed that over 14% of the variance in AUDIT scores could be explained by psychological symptom measures, and 29% of the variance in suicide risk was explained by a model using both alcohol and mental health measures. Conclusions: Findings suggest that psychological distress is associated with hazardous drinking, and that more consistent screening and referral for these issues, as well as multi-level interventions, are needed to effectively address these behavioral health concerns among firefighters.

Occupational Hazards: The Impact of Streptococcus suis Infections in Portuguese Pig Farming

Abstract Background In Portugal, the commensal and opportunistic bacteria Streptococcus suis is prevalent among pigs. Recognizing its public health significance, this systematic review investigates the relationship between occupational exposure in pig farming and the incidence of S. suis infections among workers. The importance of this study is to identify high-risk occupational activities and formulate effective public health interventions. Methods This review analyzed 20 scientific studies from 1986 to 2023 on human infections with S. suis in Portugal. The primary sources included articles in Portuguese from databases like MedLine, Scopus, and Pubmed. Studies were selected based on their focus on occupational exposure and the details provided on epidemiological context, clinical presentations, and outcomes. Results The review found that 85% of infection cases occurred in occupational settings, particularly among butchers (53%) and pig breeders or handlers (29%). Clinical manifestations predominantly included acute bacterial meningitis, with significant occurrences of neurosensory hearing loss as a sequelae. The average age of affected individuals was 44, predominantly male. Conclusions The study confirms a significant correlation between occupational exposure in pig farming and S. suis infections in humans. The findings underscore the need for stringent occupational health measures and integrated approaches encompassing human, animal, and environmental health under the One Health initiative. Innovations in public health interventions recommended include enhanced surveillance, improved workplace hygiene, and targeted health education for at-risk populations. Key messages • Occupational exposure in pig farming is a significant risk factor for S. suis infections in humans. • Integrative One Health approaches are essential for preventing S. suis infections in occupational settings.

ASSESSMENT OF NURSES' KNOWLEDGE REGARDING PERSONAL PROTECTIVE EQUIPMENT AT TERTIARY CARE HOSPITAL LAHORE

Personal Protective Equipment (PPE) is crucial for protecting healthcare workers from occupational hazards and infections, particularly in high-risk environments such as hospitals. Adequate knowledge and proper use of PPE are essential to ensure the safety of both healthcare workers and patients. This study aimed to assess the knowledge, attitudes, and practices of nurses regarding PPE at a tertiary care hospital in Lahore, Pakistan. Methods: A descriptive cross-sectional study design was utilized. A structured questionnaire was used to collect data from 152 nurses working in various departments of the hospital. Purposive sampling was employed, and the sample size was determined using RaoSoft with a 95% confidence interval and a 0.5% margin of error. The questionnaire comprised sections on demographic information, knowledge assessment, and attitudes and practices evaluation. Data were analyzed using SPSS version 25.0, with descriptive statistics and chi-square tests to identify associations between demographic characteristics and knowledge levels. Results: Of the 152 participants, 77% were female, with a mean age of 36.5 years (SD ± 9.05 years). Most participants held a diploma in nursing (46%), and the majority (93.4%) had less than 12 years of professional experience. The findings revealed that 67% of nurses demonstrated good knowledge of PPE, 20% had average knowledge, and 13% exhibited poor knowledge. While 92% of participants reported being knowledgeable about PPE usage, inconsistencies were noted in the adherence to specific practices, such as glove and mask usage. Additionally, only 34% of participants believed that consistent use of PPE would reduce their risk of infection, indicating a potential gap between perceived and actual knowledge. Conclusion: The study highlights both strengths and gaps in nurses' knowledge and practices regarding PPE at a tertiary care hospital in Lahore. While most nurses demonstrated a satisfactory understanding of PPE, inconsistencies in practical application underscore the need for targeted training and reinforcement of guidelines. Regular training sessions, active monitoring, and continuous professional development are essential to enhance adherence to PPE protocols and safeguard healthcare workers in resource-limited settings like Pakistan.

“When the Bills Keep on Coming:” the Experiences of Seafood Processors During the COVID-19 Pandemic

ABSTRACT Essential workers were at increased risk during the COVID-19 pandemic, including seafood processors who are often rendered invisible within the public sphere. To examine the health and safety concerns of seafood processors, many who are low income or im/migrant workers on H-2B visas, our team conducted qualitative research with 44 participants. We found that in addition to high occupational health hazards that existed before the pandemic, COVID-19 increased workers’ financial risks, which put them in more dangerous health and safety positions, since they needed to work through physical and mental health illness. These financial risks can be seen through the themes of paid sick leave, mental health, economic duress, and primary care access. We conclude with three recommendations to the H-2B visa worker program, which will not only decrease health disparities for im/migrant workers, but also increase health equity across seafood worker populations.

Characterising the Chemical Composition of Bushfire Smoke and Implications for Firefighter Exposure in Western Australia

This study evaluates bushfire smoke as a workplace hazard for firefighters by characterising its chemical composition and potential health risks in Western Australia. Portable Fourier Transform Infrared (FTIR) spectrometry was used to measure airborne chemical concentrations at prescribed burns across five regions, including peat (acid sulphate) fire events. Samples were collected during both flaming and smouldering phases, as well as in perceived “clear” air resting zones. Results indicated that carbon monoxide (CO) was the dominant gas, reaching concentrations of 205 ppm at the fire front, followed by nitrogen monoxide (26 ppm) and methane (19 ppm). Peat fires produced distinct profiles, with ammonia (21.5 ppm) and sulphur dioxide (9.5 ppm) concentrations higher than those observed in typical bushfires. Smouldering phases emitted higher chemical concentrations than flaming phases 75% of the time. Even clear air zones contained measurable chemicals, with CO levels averaging 18 ppm, suggesting that firefighters are not free from exposure during rest periods. These findings highlight the need for fit-for-purpose respiratory protective equipment (RPE) and improved rest protocols to minimise exposure. The study underscores the importance of comprehensive health monitoring programs for firefighters to mitigate long-term health risks.

A Hazardous Duty: Occupational Health Challenges for Traffic Police at Koshi Province

Abstract Background: Traffic police officers are integral to maintaining urban traffic flow and safety, yet their occupational roles expose them to a variety of health hazards. This study investigates the spectrum of occupational health hazards faced by traffic police officers in Koshi Province. Methods: A cross-sectional study was conducted involving 175 traffic police officers in Koshi Province. Data were collected through structured questionnaires, physical examinations, and environmental assessments. The study evaluated the prevalence of various health issues and their association with identified occupational hazards. Results: Findings reveal high prevalence rates of respiratory ailments (35%), musculoskeletal disorders (28%), stress and anxiety (40%), hearing impairments (15%), and exposure to vehicular pollutants. Environmental assessments indicated significant levels of noise, particulate matter, and exhaust fumes in traffic hotspots. Statistical analysis identified prolonged exposure duration as significant predictors of adverse health outcomes. Conclusion: Traffic police officers in Koshi Province are susceptible to multiple occupational health hazards, necessitating comprehensive intervention strategies include enhancing protective measures, implementing regular health screenings, and establishing mental health support systems. Keywords: Occupational health hazard, traffic police, Koshi Province

Evaluating the Serum Zinc and Testosterone Levels of Carpenters in Enugu Metropolis, South East Nigeria: A Cross-sectional Study

Background: Exposure to wood dust remains a pervasive occupational hazard with significant health implications Aim: This study aims to investigate the impact of occupational exposure to wood dust on the zinc and testosterone levels of carpenters and to explore its potential implications for their fertility. Materials and Methods: This cross sectional study employed simple random sampling to recruit forty carpenters and forty administrative staff after obtaining informed consent. The ethics committee of the University of Nigeria Teaching Hospital approved of the study. Serum zinc was analyzed with atomic absorption spectroscopy while testosterone was analyzed with the Fluorescence Immunchromatogarphy. Graph pad prism version 7 was used to analyze the data obtained from the study and a p value of 0.05 was used to ascertain statistical significance. Results: The mean zinc level of the test group (48.80 ± 0.83) µg/dl is statistically significantly lower than the reference group (52.40 ± 0.79) µg/dl, (p=0.003). The mean serum testosterone level of the test group (4.11± 0.10) ng/ml is statistically significantly lower than the reference group (4.51 ± 0.11) ng/ml, (p=0.010). Conclusion: These findings may suggest that occupational exposure to wood dust could potentially influence the serum levels of Zinc and testosterone levels.

Self-perceptual blindness to mental fatigue in mining workers.

Mental fatigue is a psychophysiological state that adversely impacts performance in cognitive tasks, increasing risk of occupational hazards. Given its manifestation as a conscious sensation, it is often measured through subjective self-report. However, subjective measures are not always true measurements of objective fatigue. In this study, we investigated the relationship between objective and subjective fatigue measurements with the preventive AccessPoint fatigue assay in Chilean mine workers. Subjective fatigue was measured through the Samn-Perelli scale, objective fatigue through a neurocognitive reaction time task. We found that objective and subjective fatigue do not correlate (-0.03 correlation coefficient, p < 0.001). Moreover, severe fatigue cases often displayed absence of subjective fatigue coupled with worse cognitive performance, a phenomenon we denominated Perceptual Blindness to fatigue. These findings highlight the need for objective fatigue measurements, particularly in high-risk occupational settings such as mining. Our results open new avenues for researching mechanisms underlying fatigue perception and its implications for occupational health and safety.

Socioeconomic status, smoking, and lung cancer: mediation and bias analysis in the SYNERGY study.

Increased lung-cancer risks for low socioeconomic status (SES) groups are only partially attributable to smoking habits. Little effort has been made to investigate the persistent risks related to low SES by quantification of potential biases. Based on 12 case-control studies, including 18 centers of the international SYNERGY project (16,550 cases, 20,147 controls), we estimated controlled direct effects (CDE) of SES on lung cancer via multiple logistic regression, adjusted for age, study center, and smoking habits, and stratified by sex. We conducted mediation analysis by inverse odds ratio weighting to estimate natural direct effects (NDE) and natural indirect effects via smoking habits. We considered misclassification of smoking status, selection bias, and unmeasured mediator-outcome confounding by genetic risk, both separately as well as by multiple quantitative bias analysis, using bootstrap to create 95% simulation intervals (SI). Mediation analysis of lung-cancer risks for SES estimated mean proportions of 43% in men and 33% in women attributable to smoking. Bias analyses decreased direct effects of SES on lung cancer, with selection bias showing the strongest reduction in lung-cancer risk in the multiple bias analysis. Lung-cancer risks remained increased for lower SES groups, with higher risks in men [4th versus 1st (highest) SES quartile: CDE 1.50 (SI 1.32-1.69)] than women [CDE 1.20 (SI 1.01-1.45)]. NDE were similar to CDE, particularly in men. Bias adjustment lowered direct lung-cancer risk estimates of lower SES groups. However, risks for low SES remained elevated, likely attributable to occupational hazards or other environmental exposures.