Exposure-Lag-Response in Longitudinal Studies: Application of Distributed-Lag Nonlinear Models in an Occupational Cohort.

Prolonged exposures can have complex relationships with health outcomes, as timing, duration, and intensity of exposure are all potentially relevant. Summary measures such as cumulative exposure or average intensity of exposure may not fully capture these relationships. We applied penalized and unpenalized distributed-lag nonlinear models (DLNMs) with flexible exposure-response and lag-response functions in order to examine the association between crystalline silica exposure and mortality from lung cancer and nonmalignant respiratory disease in a cohort study of 2,342 California diatomaceous earth workers followed during 1942-2011. We also assessed associations using simple measures of cumulative exposure assuming linear exposure-response and constant lag-response. Measures of association from DLNMs were generally higher than those from simpler models. Rate ratios from penalized DLNMs corresponding to average daily exposures of 0.4 mg/m3 during lag years 31-50 prior to the age of observed cases were 1.47 (95% confidence interval (CI): 0.92, 2.35) for lung cancer mortality and 1.80 (95% CI: 1.14, 2.85) for nonmalignant respiratory disease mortality. Rate ratios from the simpler models for the same exposure scenario were 1.15 (95% CI: 0.89, 1.48) and 1.23 (95% CI: 1.03, 1.46), respectively. Longitudinal cohort studies of prolonged exposures and chronic health outcomes should explore methods allowing for flexibility and nonlinearities in the exposure-lag-response

Traumatic Brain Injury and Firearm Use and Risk of Progressive Supranuclear Palsy Among Veterans

Background: Progressive supranuclear palsy (PSP) is a tauopathy that has a multifactorial etiology. Numerous studies that have investigated lead exposure and traumatic brain injury (TBI) as risk factors for other tauopathies, such as Alzheimer's disease, but not for PSP.Objective: We sought to investigate the role of firearm usage, as a possible indicator of lead exposure, and TBI as risk factors for PSP in a population of military veterans.Methods: We included participants from a larger case-control study who reported previous military service. Our sample included 67 PSP cases and 68 controls. Participants were administered a questionnaire to characterize firearm use in the military and occurrence of TBI.Results: Cases were significantly less educated than controls. In unadjusted analyses, the proportion of PSP cases (80.6%) and controls (64.7%) who reported use of firearms as part of their military job was positively associated with PSP, odds ratio (OR) 2.2 (95% CI: 1–5.0). There were no significant case-control differences in mean service duration. There was only a weak association with history of TBI, OR 1.6 (95% CI: 0.8–3.4). In multivariate models, firearm usage (OR 3.7, 95% CI: 1.5, 9.8) remained significantly associated with PSP.Conclusions: Our findings show a positive association between firearm usage and PSP and an inverse association between education and PSP. The former suggests a possible etiologic role of lead. Further studies are needed to confirm the potential etiologic effects of metals on PSP.The study was registered in clinicaltrials.gov. ClinicalTrials.gov Identifier: NCT00431301

Highlights of the 1990 Leesburg, Virginia, International Workshop on Retrospective Exposure Assessment for Occupational Epidemiology Studies.

The International Workshop on Retrospective Exposure Assessment for Occupational Epidemiology Studies was held on 27-31 March 1990 at Leesburg, Virginia, in the United States. The presentations and discussions focused on the selection of an approach for assessing exposures, methods of exposure assessment used in industry-based and community-based studies, the evaluation of exposure estimates through measurements of validity and precision, and areas of future research

DJ-1 isoforms in whole blood as potential biomarkers of Parkinson disease

DJ-1 is a multifunctional protein that plays an important role in oxidative stress, cell death, and synucleinopathies, including Parkinson disease. Previous studies have demonstrated that total DJ-1 levels decrease in the cerebrospinal fluid, but do not change significantly in human plasma from patients with Parkinson disease when compared with controls. In this study, we measured total DJ-1 and its isoforms in whole blood of patients with Parkinson disease at various stages, Alzheimer disease, and healthy controls to identify potential peripheral biomarkers of PD. In an initial discovery study of 119 subjects, 7 DJ-1 isoforms were reliably detected, and blood levels of those with 4-hydroxy-2-nonenal modifications were discovered to be altered in late-stage Parkinson disease. This result was further confirmed in a validation study of another 114 participants, suggesting that, unlike total DJ-1 levels, post-translationally modified isoforms of DJ-1 from whole blood are candidate biomarkers of late-stage Parkinson disease

Closing Information Gaps in Kakuma Refugee Camp: A Youth Participatory Action Research Study

This study explores the role of academic and social support on young people’s educational pursuits in Kenya’s Kakuma Refugee Camp. Pairing ethnographic methods with youth participatory action research, we find that support often manifests as abstract, decontextualized encouragement with little grounding in the educational opportunity structure. We argue that this motivational discourse generates information gaps, fueling aspirations that neither prepare youth for understanding, nor navigating the constraints they will encounter. In response, we designed a social media platform orienting Kakuma youth to the opportunity structure, while encouraging them to set realistic goals and plan accordingly. Designing a resource by, for, and with Kakuma youth, we illustrate that refugees have the rights and means to access information on which their everyday well‐being and futures depend. This study illustrates that critical understanding of local and global opportunities can empower, rather than demoralize, young people as they shape their futures in exile.HighlightsEducational support has limited value when decontextualized from opportunity structures.Critical understanding of opportunity constraints can empower, rather than demoralize, youth.Balancing hope and critical awareness is a central challenge in participatory action research, and in settings of forced displacement.Refugee youth advocate for their right to information on which their well‐being and futures depend.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147082/1/ajcp12277_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147082/2/ajcp12277.pd