Ischaemic heart disease mortality and years of work in trucking industry workers

Exposure to occupational air pollution and vascular endothelial dysfunction in workers of the steel industry in Iran

Air pollution is recognized as a risk factor for cardiovascular diseases; however, the precise underlying mechanisms remain unclear. This study investigated the impact of occupational air pollution exposure on endothelial function in workers within the steel industry. Specifically, we examined male employees in the coke-making division of the Isfahan Steel Company in Iran, as well as those in administrative roles with no known history of cardiovascular risk. Data on age, body mass index, duration of employment, blood pressure, fasting blood sugar, and lipid profile were collected. To assess endothelial function, flow-mediated dilation (FMD) was measured. The baseline brachial artery diameter was greater (mean difference [95% CI] = 0.068 mm [0.008 to 0.128]), while the FMD was lower (mean difference [95% CI] = -0.908 % [-1.740 to -0.075]) in the coke-making group than in the control group. After controlling for potential confounding variables, it was observed that working in the coke-making sector of the industry was associated with lower FMD (F = 3.954, p = .049). These findings indicated that occupational air pollution exposure among workers in the steel industry is linked to impaired endothelium-dependent vasodilation.

Acute myocardial infarctions identified in the Manitoba Occupational Disease Surveillance System: A linkage of worker's compensation and provincial health data

INTRODUCTION

The purpose of this study was to identify jobs and industries that may be associated with increased or decreased risk of myocardial infarction.

METHODS

We linked provincial health care data with Workers Compensation Board (WCB) of Manitoba claims data to create the Manitoba Occupational Disease Surveillance System (MODSS). Workers were eligible for inclusion in this study if their WCB claim listed an occupation, their claim could be linked to health data, they had an accepted non-acute myocardial infarction (AMI) compensation time loss claim and were free of a recent (<1 year) AMI diagnosis at the start of disease follow-up. AMI cases were identified as the most-responsible diagnosis in the hospitalization file (ICD-9 410 or ICD-10 I20). Cases were included if they occurred after the WCB record injury date until end of coverage, either through moving out of province, reaching age 65, death, or the end of the study period (March 1, 2020).

RESULTS

We identified 1880 incident AMIs amongst 150,022 claims recorded in the MODSS (1.25%). A number of industries and occupations were found to have higher and lower AMI rates. Care providers and educational, legal, and public protection support occupations had a lower hazard ratio (HR; 0.64; 95% confidence interval [CI]: 0.44-0.92) compared to the overall cohort. Female chefs and cooks, and male butchers and bakers had elevated AMI HRs. Both male and female transport and heavy equipment operators and related maintenance occupations had increased HRs (1.48; 95% CI: 1.30-1.67). Often male and female workers employed in the same occupations had congruent AMI risks, but this was not always the case.

CONCLUSIONS

The linkage of a WCB data set with provincial health claims data led to the identification of a number of occupations with elevated risks of AMI in Manitoba. This was most notable in the transportation industry. Identifying work areas with increased risk of AMIs could lead to targeted educational efforts and potential workplace modifications to lower this risk.

The necessity of improving cardiovascular health in commercial motor vehicle drivers

Commercial motor vehicle (CMV) drivers have an increased risk for cardiometabolic risk factors and higher rates of cardiovascular disease relative to the general population. Lifestyle factors, including the sedentary nature of driving and lack of access to healthy foods, contribute to the disproportionately high cardiovascular disease (CVD) risk among commercial vehicle (CMV) drivers. Occupational physicals represent an important opportunity to reach populations with a high prevalence and incidence of coronary artery disease who may not otherwise seek preventive care. These visits are an opportunity to discuss primary and secondary prevention, including lifestyle topics such as diet and exercise, and potentially recommend or implement preventive medical therapy when indicated. Future iterations of licensing guidelines for drivers should seek to incorporate updated recommendations regarding diet, physical activity, and preventive pharmacologic therapies.

Spatial Inequalities and Influencing Factors of Self-Rated Health and Perceived Environmental Hazards in a Metropolis: A Case Study of Zhengzhou City, China

Research on environmental pollution and public health has aroused increasing concern from international scholars; particularly, environmental hazards are among the important issues in China, focusing public attention on significant health risks. However, there are few studies concentrated on how perceived environmental hazards are characterized by spatial variation and on the impact of these risks on residents' health. Based on a large-scale survey of Zhengzhou City in 2020, we investigated how the self-rated health of residents and the environmental hazards perceived by them were spatially inequal at a fine (subdistrict) scale in Zhengzhou City, China, and examined the relationship among self-rated health, environmental hazards, and geographical context. The Getis-Ord Gi* method was applied to explore the spatially dependent contextual (neighborhood) effect on environmental health inequality, and the ordered multivariate logistic regression method was used to examine the correlative factors with environmental hazards, geographical context, and health inequality. The results reveal that self-rated health and environmental hazards were disproportionately distributed across the whole city and that these distributions showed certain spatial cluster characteristics. The hot spot clusters of self-rated health had favorable environmental quality where the hot spot clusters of environmental hazards were located and vice versa. In addition, health inequality was evident and was related to gender, income level, educational attainment, and housing area of residents, and the inequalities of environmental hazards existed with respect to income and housing area. Meanwhile, environmental risk inequalities associated with the social vulnerability of residents (the poor and those with low educational attainment) were obvious, with those residents experiencing a disproportionately high exposure to environmental hazards and reporting bad health conditions. The role of the geographical context (subdistrict location feature) also helps to explain the spatial distribution of health and environmental inequalities. Residents with better exposure to green coverage generally reported higher levels of self-rated health condition. In addition, the geographical location of the subdistrict also had a significant impact on the difference in residents' self-rated health status. The purpose of this study is to provide reference for policy makers to optimize the spatial pattern of urban public services and improve public health and environmental quality at a fine scale.

Assessment of occupational exposure to diesel particulate matter through evaluation of 1-nitropyrene and 1-aminopyrene in surface coal miners, India

DPM (diesel particulate matter) is ubiquitously present in the mining environment and is known for mutagenicity and carcinogenicity to humans. However, its health effects in surface coal mines are not well studied, particularly in India. In this study, DPM exposure and corresponding exposure biomarkers were investigated in four different surface coal mines in Central India. To document and evaluate the DPM exposure in surface coal miners, we characterized 1-NP (1-nitropyrene) in the mining environment as surrogate for DPM using Sioutas Cascade Impactor. Exposure biomarkers were analyzed by collecting post work shift (8-h work shift) urine samples and determining the concentrations of 1-aminopyrene (1-AP) as a metabolite of 1-NP and 8-hydroxydeoxyguanosine (8OHdG) as DNA damage marker. We observed high concentration of 1-NP (7.13-52.46 ng/m³) in all the mines compared with the earlier reported values. The average creatinine corrected 1-AP and 8OHdG levels ranged 0.07-0.43 [Formula: see text]g/g and 32.47-64.16 [Formula: see text]g/g, respectively, in different mines. We found 1-AP in majority of the mine workers' urine (55.53%) and its level was higher than that reported for general environmental exposure in earlier studies. Thus, the study finding indicates occupational exposure to DPM in all the four mines. However, the association between 1-NP level and exposure biomarkers (1-AP and 8OHdG) was inconsistent, which may be due to individual physiological variations. The data on exposure levels in this study will help to understand the epidemiological risk assessment of DPM in surface coal miners. Further biomonitoring and cohort study are needed to exactly quantify the occupational health impacts caused by DPM among coal miners.

Health Risks of American Long-Distance Truckers: Results From a Multisite Assessment

OBJECTIVE

The aim of this study was to assess the general and sexual health of long-haul truck drivers in the United States.

METHODS

Drivers were recruited from company sites and truck stops in North Carolina, Tennessee, and Mississippi. A sample of 266 drivers was assessed for lifestyle activities; body mass index and blood pressure were measured, and biologic samples were taken for cholesterol, diabetes, and sexually transmitted infection (STI)/HIV testing.

RESULTS

The drivers in this study had higher levels of cholesterol and higher rates of smoking, obesity, and diabetes than the U.S average. STI/HIV infection rates were lower than the U.S. average.

CONCLUSION

Long-haul truck driving is a stressful occupation with few opportunities for healthy living. Stress reduction, wellness programs, and better food and exercise options at truck stops should be adopted for the benefit of truckers and the safety of the driving public.

Cardiovascular disease and long-term occupational exposure to ultrafine particles: A cohort study of airport workers

AIM

To investigate if ischemic heart disease (IHD) and cerebrovascular disease is associated with long-term occupational exposure to ultrafine particles (UFP) outdoors at an airport.

METHODS AND RESULTS

This is a register-based follow-up study based on a cohort comprising an exposed group of 6515 men employed in unskilled work at Copenhagen Airport and a reference group of 61,617 men in unskilled work in other firms in greater Copenhagen during 1990-2012. The exposure was assessed from information on proportion of time spent on the airport apron for each calendar year (apron-years) and the primary exposure measure was cumulated apron-years. The cohort was merged to the National Patient Register that includes data on all contacts to public and private hospitals in Denmark and the Register of Causes of Death. Risk estimates were provided by Poisson regression and adjusted for age, calendar year and educational level. We found no associations between cumulative apron-years and IHD (IRR, 1.00; 95%CI, 0.97-1.03) or cerebrovascular disease (IRR, 1.00; 0.98-1.02) when adjusted for confounders.

CONCLUSION

In this large cohort study, we found no association between outdoor occupational exposure to UFP and IHD and cerebrovascular disease.

Value Assessment of Health Losses Caused by PM2.5 Pollution in Cities of Atmospheric Pollution Transmission Channel in the Beijing⁻Tianjin⁻Hebei Region, China

A set of exposure–response coefficients between fine particulate matter (PM_2.5) pollution and different health endpoints were determined through the meta-analysis method based on 2254 studies collected from the Web of Science database. With data including remotely-sensed PM_2.5 concentration, demographic data, health data, and survey data, a Poisson regression model was used to assess the health losses and their economic value caused by PM_2.5 pollution in cities of atmospheric pollution transmission channel in the Beijing–Tianjin–Hebei region, China. The results showed the following: (1) Significant exposure–response relationships existed between PM_2.5 pollution and a set of health endpoints, including all-cause death, death from circulatory disease, death from respiratory disease, death from lung cancer, hospitalization for circulatory disease, hospitalization for respiratory disease, and outpatient emergency treatment. Each increase of 10 μg/m³ in PM_2.5 concentration led to an increase of 5.69% (95% CI (confidence interval): 4.12%, 7.85%), 6.88% (95% CI: 4.94%, 9.58%), 4.71% (95% CI: 2.93%, 7.57%), 9.53% (95% CI: 6.84%, 13.28%), 5.33% (95% CI: 3.90%, 7.27%), 5.50% (95% CI: 4.09%, 7.38%), and 6.35% (95% CI: 4.71%, 8.56%) for above-mentioned health endpoints, respectively. (2) PM_2.5 pollution posed a serious threat to residents’ health. In 2016, the number of deaths, hospitalizations, and outpatient emergency visits induced by PM_2.5 pollution in cities of atmospheric pollution transmission channel in the Beijing–Tianjin–Hebei region reached 309,643, 1,867,240, and 47,655,405, respectively, accounting for 28.36%, 27.02% and 30.13% of the total number of deaths, hospitalizations, and outpatient emergency visits, respectively. (3) The economic value of health losses due to PM_2.5 pollution in the study area was approximately $28.1 billion, accounting for 1.52% of the gross domestic product. The economic value of health losses was higher in Beijing, Tianjin, Shijiazhuang, Zhengzhou, Handan, Baoding, and Cangzhou, but lower in Taiyuan, Yangquan, Changzhi, Jincheng, and Hebi.

Ischemic Heart Disease Mortality and Diesel Exhaust and Respirable Dust Exposure in the Diesel Exhaust in Miners Study

Diesel exhaust is a suggested risk factor for ischemic heart disease (IHD), but evidence from cohorts using quantitative exposure metrics is limited. We examined the impact of respirable elemental carbon (REC), a key surrogate for diesel exhaust, and respirable dust (RD) on IHD mortality, using data from the Diesel Exhaust in Miners Study in the United States. Using data from a cohort of male workers followed from 1948-1968 until 1997, we fitted Cox proportional hazards models to estimate hazard ratios for IHD mortality for cumulative and average intensity of exposure to REC and RD. Segmented linear regression models allowed for nonmonotonicity. Hazard ratios for cumulative and average REC exposure declined relative to the lowest exposure category before increasing to 0.79 and 1.25, respectively, in the highest category. Relative to the category containing the segmented regression change points, hazard ratios for the highest category were 1.69 and 1.54 for cumulative and average REC exposure, respectively. Hazard ratios for RD exposure increased across the full exposure range to 1.33 and 2.69 for cumulative and average RD exposure, respectively. Tests for trend were statistically significant for cumulative REC exposure (above the change point) and for average RD exposure. Our findings suggest excess risk of IHD mortality in relation to increased exposure to REC and RD.

Health Risks Associated with Occupational Exposure to Ambient Air Pollution in Commercial Drivers: A Systematic Review

Ambient air pollution is a major global health problem and commercial drivers are particularly exposed to it. As no systematic assessment of the health risks associated with occupational exposure to ambient air pollution in this population had yet been carried out, we conducted a systematic review using a protocol-driven strategy. Papers published from inception to April 20, 2018 in MEDLINE, EMBASE, CINAHL, African journals online, the Cochrane library, ISRCTN WHO ICTRP, and the Web of Science and Scopus databases were screened for inclusion by two independent reviewers. Original articles with at least an available abstract in English or French were included. The initial search retrieved 1454 published articles of which 20 articles were included. Three studies reported a significant difference in white blood cells (10⁶/L) among commercial motorcyclists compared to rural inhabitants (5.041 ± 1.209 vs. 5.900 ± 1.213, p = 0.001), an increased risk of lung cancer (RR = 1.6, 95%CI 1.5–1.8) in bus drivers and an increased standardized mortality ratio (SMR) in bus drivers from Hodgkin’s lymphoma (SMR 2.17, 95%CI 1.19–3.87) compared to white-collar workers. Other studies also found that drivers had more oxidative DNA damage and chromosome breaks. Four papers failed to demonstrate that the drivers were more exposed to air pollution than the controls. Three other studies also reported no significant difference in lung function parameters and respiratory symptoms. The genetic polymorphisms of detoxifying enzymes were also not homogeneously distributed compared to the controls. There is some evidence that occupational exposure to ambient air pollution among commercial drivers is associated with adverse health outcomes, but the existing literature is limited, with few studies on small sample size, methodological weaknesses, and contradictory findings—thus, further research is recommended.

Perception and reality of particulate matter exposure in New York City taxi drivers

Exposure to fine particulate matter (PM2.5) and black carbon (BC) have been linked to negative health risks, but exposure among professional taxi drivers is understudied. This pilot study measured drivers' knowledge, attitudes, and beliefs (KAB) about air pollution compared with direct measures of exposures. Roadside and in-vehicle levels of PM2.5 and BC were continuously measured over a single shift on each subject, and exposures compared with central site monitoring. One hundred drivers completed an air pollution KAB questionnaire, and seven taxicabs participated in preliminary in-cab air sampling. Taxicab PM2.5 and BC concentrations were elevated compared with nearby central monitoring. Average PM2.5 concentrations per 15-min interval were 4-49 μg/m3. BC levels were also elevated; reaching>10 μg/m3. Fifty-six of the 100 drivers surveyed believed they were more exposed than non-drivers; 81 believed air pollution causes health problems. Air pollution exposures recorded suggest that driver exposures would likely exceed EPA recommendations if experienced for 24 h. Surveys indicated that driver awareness of this was limited. Future studies should focus on reducing exposures and increasing awareness among taxi drivers.

Truck Drivers' Use of the Internet: A Mobile Health Lifeline

Because of their social isolation, irregular and unpredictable schedules, limited access to health care, and long periods of travel, long-haul truckers may benefit from the use of mobile health applications on Internet-capable devices. The purpose of this study was to determine Internet access and usage among a sample of long-haul truck drivers. In this cross-sectional study, truck drivers completed a pencil and paper survey with questions on demographics, work and health histories, and Internet access and usage for both personal and job reasons. A total of 106 truck drivers were recruited from trucking industry trade shows, by word of mouth, and directly from trucking companies. Overall, the truck drivers' use of the Internet was limited. Their usage for personal and job-related reasons differed. Social connectivity and access to health and wellness information were important during personal usage time. Job-related Internet use was highly practical, and applied to seeking information for directions and maps, fuel stops and pricing, and communicating with employers or transmitting documents. Age and experience were associated with Internet use. Younger, less-experienced drivers used the Internet more than older, experienced drivers. Targeted mobile health messaging may be a useful tool to inform truck drivers of health conditions and plans, and may provide links to primary care providers needing to monitor or notify drivers of diagnostic results or treatment plans.

Scientific evidence of dockworker illness to nursing clinical reasoning

OBJECTIVE

To identify scientific evidence of occupational illness of dockworkers published in the literature.

METHOD

systematic review of the literature, developed according to the Cochrane method. The databases searched were: Cochrane, LILACS, MEDLINE/PubMed, CINAHL and SciELO. Studies from 1988 to 2014 were selected. The data were analyzed according to the level of evidence and Strengthening the Reporting of Observational Studies in Epidemiology.

RESULTS

We included 14 studies, in which 11 (78.6%) were from international journals. The year of 2012 showed greater number of studies. All studies were classified as: Level of Evidence 4, highlighting lung cancer, musculoskeletal and ischemic diseases, causal link in chemical risks.

CONCLUSION

The development of preventive measures should especially include chemical exposure of workers applying the clinical reasoning of nurses' environmental knowledge to care for illnesses.

OBJETIVO

Identificar evidências científicas de adoecimento ocupacional do trabalhador portuário publicadas na literatura.

MÉTODO

Revisão sistemática da literatura, construída conforme o método Cochrane. As bases de dados pesquisadas foram Cochrane, LILACS, MEDLINE/PubMed, CINAHL e SciELO. Foram selecionados artigos publicados de 1988 a 2014. Os dados foram analisados conforme o Nível de Evidência e Strengthening the Reporting of Observational Studies in Epidemiology.

RESULTADOS

Foram selecionadas 14 publicações, das quais 11 (78,6%) de revistas internacionais. O ano de 2012 reuniu maior número de publicações no período de estudo. Todas as publicações pertenciam ao Nível de Evidência 4, destacando o câncer pulmonar, doenças osteomusculares e isquêmicas, com nexo causal nos riscos químicos.

CONCLUSÃO

A elaboração de medidas preventivas deve prever especialmente a exposição química do trabalhador, aplicando ao raciocínio clínico do enfermeiro um conhecimento ambiental para a assistência aos adoecimentos.

Occupational vehicle-related particulate exposure and inflammatory markers in trucking industry workers

BACKGROUND

Previous studies have suggested an association between particulate air pollution and cardiovascular disease, but the mechanism is still unclear.

OBJECTIVE

We examined the association between workplace exposure to vehicle-related particles and cardiovascular disease related systemic inflammatory markers, C-reactive protein (hs-CRP), soluble intercellular adhesion molecule-1 (sICAM-1), and interleukin-6 (IL-6) in 137 trucking terminal workers (non-drivers) in the U.S. trucking industry.

METHODS

We visited two large trucking terminals in 2009 and measured vehicle-related elemental carbon (EC), organic carbon (OC), and particulate matter with aerodynamic diameter ≤2.5µm (PM2.5), for 5 days consecutively at the main work areas. Each participant provided a blood sample and completed a health questionnaire during the sampling period. Individual workplace exposure level was calculated by 12-h time weighted moving averages based on work shift. The association between each blood marker and exposure to each pollutant during 0-12, 12-24, 24-36, and 36-48h before the blood draw was examined by multivariable regression analyses.

RESULTS

In general, OC and EC had a positive association with sICAM-1, especially for exposure periods 12-24 (lag12-24) and 24-36 (lag24-36)h prior to blood draw [β=54.9 (95%CI: 12.3-97.5) for lag12-24 and β=46.5 (95%CI: 21.2-71.8) for lag12-24; change in sICAM-1 (in ng/mL) corresponding to an IQR increase in OC]. A similar pattern was found for EC and PM2.5. We did not find an association between measured pollutants up to 48h before blood draw and hs-CRP or IL-6.

CONCLUSION

In this group of healthy workers, short-term exposure to vehicle-related air pollutants may be associated with sICAM-1. Our findings may be dependent on the exposure period studied.

Addressing Emerging Risks: Scientific and Regulatory Challenges Associated with Environmentally Persistent Free Radicals

Airborne fine and ultrafine particulate matter (PM) are often generated through widely-used thermal processes such as the combustion of fuels or the thermal decomposition of waste. Residents near Superfund sites are exposed to PM through the inhalation of windblown dust, ingestion of soil and sediments, and inhalation of emissions from the on-site thermal treatment of contaminated soils. Epidemiological evidence supports a link between exposure to airborne PM and an increased risk of cardiovascular and pulmonary diseases. It is well-known that during combustion processes, incomplete combustion can lead to the production of organic pollutants that can adsorb to the surface of PM. Recent studies have demonstrated that their interaction with metal centers can lead to the generation of a surface stabilized metal-radical complex capable of redox cycling to produce ROS. Moreover, these free radicals can persist in the environment, hence their designation as Environmentally Persistent Free Radicals (EPFR). EPFR has been demonstrated in both ambient air PM_2.5 (diameter < 2.5 µm) and in PM from a variety of combustion sources. Thus, low-temperature, thermal treatment of soils can potentially increase the concentration of EPFR in areas in and around Superfund sites. In this review, we will outline the evidence to date supporting EPFR formation and its environmental significance. Furthermore, we will address the lack of methodologies for specifically addressing its risk assessment and challenges associated with regulating this new, emerging contaminant.

Exposure to occupational air pollution and cardiac function in workers of the Esfahan Steel Industry, Iran

Air pollution is recognized as an important risk factor for cardiovascular disease. We investigated association of exposure to occupational air pollution and cardiac function in the workers of the steel industry. Fifty male workers of the agglomeration and coke-making parts of the Esfahan Steel Company were randomly selected (n = 50). Workers in the administrative parts were studied as controls (n = 50). Those with known history of hypertension, dyslipidemia, or diabetes, and active smokers were not included. Data of age, body mass index, employment duration, blood pressure, fasting blood sugar, and lipid profile were gathered. Echocardiography was performed to evaluate cardiac function. Left ventricular ejection fraction was lower in workers of the agglomeration/coke-making parts than in controls (mean difference = 5 to 5.5 %, P < 0.001). Mild right ventricular dilatation and grade I pulmonary hypertension were present in three (12 %) workers of the coke-making part, but none of the controls (P = 0.010). According to these results, occupational air pollution exposure in workers of the steel industry is associated with left heart systolic dysfunction. Possible right heart insults due to air pollution exposure warrant further investigations.

Associations of work hours, job strain, and occupation with endothelial function: the Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

To investigate associations of work hours, job control, job demands, job strain, and occupational category with brachial artery flow-mediated dilation (FMD) in 1499 Multi-Ethnic Study of Atherosclerosis participants.

METHODS

Flow-mediated dilation was obtained using high-resolution ultrasound. Mean values of FMD were examined across categories of occupation, work hours, and the other exposures using regression analyses.

RESULTS

Occupational category was significantly associated with FMD overall, with blue-collar workers showing the lowest mean values-management/professional = 4.97 ± 0.22%; sales/office = 5.19 ± 0.28%; services = 4.73 ± 0.29%; and blue-collar workers = 4.01 ± 0.26% (adjusted P < 0.001). There was evidence of effect modification by sex (interaction P = 0.031)-significant associations were observed among women (adjusted P = 0.002) and nearly significant results among men (adjusted P = 0.087). Other exposures were not significantly associated with FMD.

CONCLUSIONS

Differences in endothelial function may account for some of the variation in cardiovascular disease across occupational groups.

Short-term traffic related exposures and biomarkers of nitro-PAH exposure and oxidative DNA damage

Exposure to vehicle exhaust has been associated with cardiac and respiratory disease, lung cancer, and greater overall mortality. We investigated whether amino- polycyclic aromatic hydrocarbon (amino-PAH) metabolites of nitro-PAHs could be used as biomarkers of these exposures. Pre- and post-shift urine samples were collected at the beginning and end of a work week from 82 male U.S trucking industry workers. We used repeated-measures analysis to examine associations of total 1- and 2-aminonaphthalene (1 & 2-AN) and 1-aminopyrene (1-AP) urinary concentrations with microenvironment exposures to particulate matter (PM_2.5), elemental and organic carbon, and between 1&2-AN and 1-AP with urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG). There was an association between work week mean PM_2.5 levels and post-shift 1 & 2-AN, [141.8 pg/ml increase (95% CI:53.3, 230.2) for each IQR increase (5.54 µg/m³) in PM_2.5,] but no associations with other exposure measures. There was a statistically significant increase in 8-OHdG concentrations with 1 & 2-AN (2.38 µg/mg creatinine (95%CI: 0.19, 4.58) per 242.85 pg/mg creatinine increase in 1 & 2-AN), and suggestive associations with all other exposure measures. Our findings suggest associations between urinary amino-PAHs with vehicle exhaust related PM_2.5 as well as with a biomarker of oxidative DNA damage.

A structural approach to address the healthy-worker survivor effect in occupational cohorts: an application in the trucking industry cohort

BACKGROUND

Occupational cohort studies are often challenged by the Healthy Worker Survivor Effect, which may bias standard methods of analysis. G-estimation of structural failure time models is an approach for reducing this type of bias. Accelerated failure time models have recently been applied in an occupational cohort but cumulative failure time models have not.

METHODS

We used g-estimation of a cumulative failure time model to assess the effect of working as a long-haul driver on ischaemic heart disease mortality in a cohort of 30 448 men employed in the unionised US trucking industry in 1985. Exposure was defined by job title and based on work records. We also applied g-estimation of an accelerated failure time model as a sensitivity analysis and approximated HRs from both models to compare them.

RESULTS

The risk ratio (RR) obtained from the cumulative failure time model, comparing the observed risk under no intervention to the risk had nobody ever been exposed as a long-haul driver, was 1.09 (95% CI 1.02 to 1.16). The RR comparing the risk had everyone been exposed as long-haul driver for 8 years to the risk had nobody ever been exposed was 1.20 (95% CI 1.04 to 1.46). After HR approximations, accelerated failure time model results were similar.

CONCLUSIONS

The cumulative failure time model can effectively control time-varying confounding by Healthy Worker Survivor Effect, and provides an easily interpretable effect estimate. RRs estimated from the cumulative failure time model indicate an elevated ischaemic heart disease mortality risk for long-haul drivers in the US trucking industry.

Traffic-related exposures and biomarkers of systemic inflammation, endothelial activation and oxidative stress: a panel study in the US trucking industry

BACKGROUND

Experimental evidence suggests that inhaled particles from vehicle exhaust have systemic effects on inflammation, endothelial activation and oxidative stress. In the present study we assess the relationships of short-term exposures with inflammatory endothelial activation and oxidative stress biomarker levels in a population of trucking industry workers.

METHODS

Blood and urine samples were collected pre and post-shift, at the beginning and end of a workweek from 67 male non-smoking US trucking industry workers. Concurrent measurements of microenvironment concentrations of elemental and organic carbon (EC & OC), and fine particulate matter (PM2.5) combined with time activity patterns allowed for calculation of individual exposures. Associations between daily and first and last-day average levels of exposures and repeated measures of intercellular and vascular cell adhesion molecule-1 (ICAM-1 & VCAM-1), interleukin 6 (IL-6) and C-reactive protein (CRP) blood levels and urinary 8-Hydroxy-2'-Deoxyguanosine (8-OHdG) were assessed using linear mixed effects models for repeated measures.

RESULTS

There was a statistically significant association between first and last-day average PM2.5 and 8-OHdG (21% increase, 95% CI: 2, 42%) and first and last-day average OC and IL-6 levels (18% increase 95% CI: 1, 37%) per IQR in exposure. There were no significant findings associated with EC or associations suggesting acute cross-shift effects.

CONCLUSION

Our findings suggest associations between weekly average exposures of PM2.5 on markers of oxidative stress and OC on IL-6 levels.