Challenges In Exposure Assessment Research Articles

Air pollution and childhood cancer: Methodological challenges in exposure assessment for epidemiological research

Air pollution and childhood cancer: Methodological challenges in exposure assessment for epidemiological research

Sixteen-Year Monitoring of Particulate Matter Exposure in the Parisian Subway: Data Inventory and Compilation in a Database

The regularly reported associations between particulate matter (PM) exposure, and morbidity and mortality due to respiratory, cardiovascular, cancer, and metabolic diseases have led to the reduction in recommended outdoor PM10 and PM2.5 exposure limits. However, indoor PM10 and PM2.5 concentrations in subway systems in many cities are often higher than outdoor concentrations. The effects of these exposures on subway workers and passengers are not well known, mainly because of the challenges in exposure assessment and the lack of longitudinal studies combining comprehensive exposure and health surveillance. To fulfill this gap, we made an inventory of the PM measurement campaigns conducted in the Parisian subway since 2004. We identified 5856 PM2.5 and 18,148 PM10 results from both personal and stationary air sample measurements that we centralized in a database along with contextual information of each measurement. This database has extensive coverage of the subway network and will enable descriptive and analytical studies of indoor PM exposure in the Parisian subway and its potential effects on human health.

Work Activities, Self-Reported Symptoms, and Diminished Lung Function in a Population of Predominantly Hispanic Industrial Hog Operation Workers in North Carolina, United States

Background/Aim: Although swine worker respiratory disease is established, evidence is mainly from predominantly Caucasian farm-owner-operator cohorts whose work exposures may differ from laborers hired to perform day-to-day intensive swine production jobs in confinement barns. The Rural Empowerment Association for Community Help (REACH) has initiated community-based participatory research (CBPR) with Hispanic laborers hired to work in industrial hog operations (IHOs) in eastern North Carolina. Together with REACH, we investigated whether such IHO workers’ occupational exposures were related to respiratory health outcomes. Methods: During 2013-14, we completed a 4-month CBPR panel study, involving baseline and 8 bi-weekly visits to collect demographic, personal, and work exposure data and spirometry measurements. We assessed the relation of IHO work activities with respiratory outcomes at baseline (linear regression) and longitudinally (fixed-effects ordinal logistic regression), adjusting for potential confounders. Results: One hundred and three IHO workers were enrolled (88% Hispanic; 46% male; age mean[±SD] 38±11 years) and completed 782 bi-weekly visits. Asthma prevalence was 8.7% and 92.6% were non-smokers. At baseline, total number of years of IHO work was negatively associated with forced expiratory volume (L) in the first second (FEV1) (ß=-0.031; 95% confidence interval [CI]: -0.060, -0.001). Longitudinally, positive associations were observed between pressure washing barns and coughing (odds ratio [OR]=3.8; 95%CI: 1.2, 12.3), herd changes and nasal congestion (OR=7.4; 95%CI: 1.2, 44.6) and confinement barn ventilation fans turned off and difficulty breathing (OR=11.2; 95% CI: 2.8, 44.4), eye irritation (OR=5.8; 95%CI: 1.1, 30.7), and chills (OR=5.1; 95%CI: 3.0, 8.9). Conclusions: In a predominantly Hispanic cohort of IHO workers, we observed relations between IHO work activities and adverse respiratory outcomes, particularly prolonged IHO employment and activities that aerosolize and keep waste in-barn. Challenges in exposure assessment from lack of on-IHO access and worker reluctance to enroll in cohorts can be mitigated using an empowering CBPR approach.

Abstracts of the 28th Annual Conference of the International Society for Environmental Epidemiology (ISEE), 1-4 September 2016, Rome, Italy.

The 28th annual conference of the International Society for Environmental Epidemiology was held 1 - 4 September 2016 in Rome, Italy. The conference theme was "Old and New Risks: Challenges for Environmental Epidemiology." The focus of this year's conference is current and future challenges in exposure assessment, study design, and data analyses.

What Can Epidemiological Studies Tell Us about the Impact of Chemical Mixtures on Human Health?

SummaryHumans are exposed to a large number of environmental chemicals: Some of these may be toxic, and many others have unknown or poorly characterized health effects. There is intense interest in determining the impact of exposure to environmental chemical mixtures on human health. As the study of mixtures continues to evolve in the field of environmental epidemiology, it is imperative that we understand the methodologic challenges of this research and the types of questions we can address using epidemiological data. In this article, we summarize some of the unique challenges in exposure assessment, statistical methods, and methodology that epidemiologists face in addressing chemical mixtures. We propose three broad questions that epidemiological studies can address: a) What are the potential health impacts of individual chemical agents? b) What is the interaction among agents? And c) what are the health effects of cumulative exposure to multiple agents? As the field of mixtures research grows, we can use these three questions as a basis for defining our research questions and for developing methods that will help us better understand the effect of chemical exposures on human disease and well-being.

Parkinson's Disease and Residential Exposure to Maneb and Paraquat From Agricultural Applications in the Central Valley of California

Evidence from animal and cell models suggests that pesticides cause a neurodegenerative process leading to Parkinson's disease (PD). Human data are insufficient to support this claim for any specific pesticide, largely because of challenges in exposure assessment. The authors developed and validated an exposure assessment tool based on geographic information systems that integrated information from California Pesticide Use Reports and land-use maps to estimate historical exposure to agricultural pesticides in the residential environment. In 1998-2007, the authors enrolled 368 incident PD cases and 341 population controls from the Central Valley of California in a case-control study. They generated estimates for maneb and paraquat exposures incurred between 1974 and 1999. Exposure to both pesticides within 500 m of the home increased PD risk by 75% (95% confidence interval (CI): 1.13, 2.73). Persons aged < or =60 years at the time of diagnosis were at much higher risk when exposed to either maneb or paraquat alone (odds ratio = 2.27, 95% CI: 0.91, 5.70) or to both pesticides in combination (odds ratio = 4.17, 95% CI: 1.15, 15.16) in 1974-1989. This study provides evidence that exposure to a combination of maneb and paraquat increases PD risk, particularly in younger subjects and/or when exposure occurs at younger ages.