Angela Hobson

Increased risk of parkinsonism associated with welding exposure

OBJECTIVE Manganese (Mn), an established neurotoxicant, is a common component of welding fume. The neurological phenotype associated with welding exposures has not been well described. Prior epidemiologic evidence linking occupational welding to parkinsonism is mixed, and remains controversial. METHODS This was a cross-sectional and nested case-control study to investigate the prevalence and phenotype of parkinsonism among 811 shipyard and fabrication welders recruited from trade unions. Two reference groups included 59 non-welder trade workers and 118 newly diagnosed, untreated idiopathic PD patients. Study subjects were examined by a movement disorders specialist using the Unified Parkinson Disease Rating Scale motor subsection 3 (UPDRS3). Parkinsonism cases were defined as welders with UPDRS3 score ≥15. Normal was defined as UPDRS3<6. Exposure was classified as intensity adjusted, cumulative years of welding. Adjusted prevalence ratios for parkinsonism were calculated in relation to quartiles of welding years. RESULTS The overall prevalence estimate of parkinsonism was 15.6% in welding exposed workers compared to 0% in the reference group. Among welders, we observed a U-shaped dose-response relation between weighted welding exposure-years and parkinsonism. UPDRS3 scores for most domains were similar between welders and newly diagnosed idiopathic Parkinson disease (PD) patients, except for greater frequency of rest tremor and asymmetry in PD patients. CONCLUSION This work-site based study among welders demonstrates a high prevalence of parkinsonism compared to nonwelding-exposed workers and a clinical phenotype that overlaps substantially with PD.

Basal ganglia intensity indices and diffusion weighted imaging in manganese-exposed welders

Objectives Manganese exposure leads to diffuse cerebral metal deposition with the highest concentration in the globus pallidus associated with increased T1-weighted MRI signal. T1 signal intensity in extra-pallidal basal ganglia (caudate and putamen) has not been studied in occupationally exposed workers. Diffusion weighted imaging is a non-invasive measure of neuronal damage and may provide a quantification of neurotoxicity associated with welding and manganese exposure. This study investigated extra-pallidal T1 basal ganglia signal intensity as a marker of manganese exposure and basal ganglia diffusion weighted imaging abnormalities as a potential marker of neurotoxicity. Methods A 3T MR case:control imaging study was performed on 18 welders and 18 age- and gender-matched controls. Basal ganglia regions of interest were identified for each subject. T1-weighted intensity indices and apparent diffusion coefficients were generated for each region. Results All regional indices were higher in welders than controls (p≤0.05). Combined basal ganglia (ρ=0.610), caudate (ρ=0.645), anterior (ρ=0.595) and posterior putamen (ρ=0.511) indices were more correlated with exposure than pallidal (ρ=0.484) index. Welder apparent diffusion coefficient values were lower than controls for globus pallidus (p=0.03) and anterior putamen (p=0.004). Conclusions Welders demonstrated elevated T1 indices throughout the basal ganglia. Combined basal ganglia, caudate and putamen indices were more correlated with exposure than pallidal index suggesting more inclusive basal ganglia sampling results in better exposure markers. Elevated indices were associated with diffusion weighted abnormalities in the pallidum and anterior putamen suggesting neurotoxicity in these regions.

Estimation of Particulate Mass and Manganese Exposure Levels among Welders

BACKGROUND Welders are frequently exposed to Manganese (Mn), which may increase the risk of neurological impairment. Historical exposure estimates for welding-exposed workers are needed for epidemiological studies evaluating the relationship between welding and neurological or other health outcomes. The objective of this study was to develop and validate a multivariate model to estimate quantitative levels of welding fume exposures based on welding particulate mass and Mn concentrations reported in the published literature. METHODS Articles that described welding particulate and Mn exposures during field welding activities were identified through a comprehensive literature search. Summary measures of exposure and related determinants such as year of sampling, welding process performed, type of ventilation used, degree of enclosure, base metal, and location of sampling filter were extracted from each article. The natural log of the reported arithmetic mean exposure level was used as the dependent variable in model building, while the independent variables included the exposure determinants. Cross-validation was performed to aid in model selection and to evaluate the generalizability of the models. RESULTS A total of 33 particulate and 27 Mn means were included in the regression analysis. The final model explained 76% of the variability in the mean exposures and included welding process and degree of enclosure as predictors. There was very little change in the explained variability and root mean squared error between the final model and its cross-validation model indicating the final model is robust given the available data. CONCLUSIONS This model may be improved with more detailed exposure determinants; however, the relatively large amount of variance explained by the final model along with the positive generalizability results of the cross-validation increases the confidence that the estimates derived from this model can be used for estimating welder exposures in absence of individual measurement data.

Effects of parkinsonism on health status in welding exposed workers

BACKGROUND Previous studies suggest that welders frequently display parkinsonian signs, such as bradykinesia and tremor. Demonstrating that these parkinsonian findings are associated with reductions in quality of life (QoL) or health status could have important repercussions for worker safety and performance. METHODS Subjects included 394 active workers exposed to welding fumes and evaluated for parkinsonism by movement disorders experts in a worksite-based epidemiology study. Subjects were diagnosed with parkinsonism if the Unified Parkinson Disease Rating Scale motor subsection part 3 (UPDRS3) score was ≥15. All subjects completed a Parkinsons disease (PD) symptom questionnaire and the PDQ39, a widely used QoL and health status measure for PD. RESULTS Total PDQ39 score and all subscores were greater in welders with parkinsonism than welders without parkinsonism, with the most significant differences observed for mobility, emotional well-being, and activities of daily living (ADLs). The PDQ39 scores for welding exposed workers with parkinsonism were similar to scores seen in a group of early PD patients. CONCLUSION Parkinsonism in active, welding exposed workers is associated with reductions in health status and QoL affecting a broad range of categories and within the range seen in early PD.

Development and Evaluation of an Integrated Asthma Awareness Curriculum for the Elementary School Classroom

Asthma is one of the most common causes of school absenteeism, and many children are affected by, or encounter, it in the school setting. An integrated curriculum that presents asthma as a real world example can raise all children’s awareness and understanding of asthma, not just those with the condition. A 15-lesson, asthma-based curriculum was developed to integrate with and enhance the core subjects of math, science, and communication arts. A pilot test was performed in fourth- and fifth-grade classes to assess student asthma knowledge gain, teacher acceptance, and grade appropriateness of the curriculum. During the 2006–2007 school year, 15 teachers were recruited from the St. Louis, MO, USA area to assess the curriculum through teaching and administering pre- and post-unit tests and completing a teacher evaluation for each lesson taught. Four additional classrooms served as comparisons. Paired t tests were used for each lesson taught, to evaluate pre-/post-test and classroom differences, and focus groups were used for qualitative evaluation. There was an increase in asthma knowledge between pre- and post-tests in both grades, individually and combined (p < 0.001). Intervention post-test scores were higher than comparison classroom scores (p < 0.001). Teacher feedback indicated that the lessons enhanced previously learned skills and increased students’ overall understanding of asthma. Offering asthma education in the classroom can provide an opportunity for all students to gain asthma knowledge and build health literacy about a leading chronic disease in school-aged children.

Breathe Your Best for School Success: Evaluation of an Initiative to Enhance Asthma Action Plans in the School Setting

Breathe Your Best for School Success (BYB) was a feasibility program of Asthma 411, an initiative developed to improve asthma management in the school setting as part of a Centers for Disease Control and Prevention cooperative agreement awarded to the St. Louis Regional Asthma Consortium (SLRAC). The objective of BYB was to increase the number of current provider-written asthma action plans (AAPs) submitted to the school nurse at the beginning of the school year. The Saint Louis University Institutional Review Board approved implementation and evaluation of Asthma 411 interventions. BYB was a collaborative project among the school districts and SLRAC. BYB utilized a “passport” which described the three steps to “breathe your best”: (1) obtain an AAP from a health care provider (HCP), (2) fill prescriptions at a pharmacy, and (3) give appropriate medications and the AAP to the school nurse at the beginning of the school year. The passports were designed to be attractive to students and were inserted into plastic cases attached to lanyards for easy transport by students and families. The passport included information describing the importance of each step and included space for signatures from the HCP, pharmacist, and school nurse to verify completion of each step. Incentives were offered to promote participation. To assess reasons for participation or nonparticipation in the BYB program, randomized telephone surveys with parents or guardians of children with asthma were conducted in the fall of 2007.

Public Health Seminar: Classics to Contemporary Cases for a New Pedagogy

This best practice article explains a Public Health Seminar course that represents an innovative approach to public health pedagogy with demonstrated learning impacts. Reflecting many of the new Council on Education for Public Health competencies, this required course introduces incoming MPH students to the field of public health using a series of classic and contemporary cases, critically analyzed in a small group discussion format. Other modalities include succinct weekly written reflection critiques, rotating faculty discussion leaders, and a final project using various media platforms to communicate case narratives. Key pedagogical elements support students’ knowledge and skill acquisition: (1) small group discussion format, (2) case-based learning, (3) integration across MPH curriculum, and (4) communication skill building. The Public Health Seminar course offers the opportunity to motivate students early in a program, engaging them in relevant issues and providing insight into the importance of their MPH learning and public health professional practice.

Water metal contaminants in a potentially mineral-deficient population of Haiti

ABSTRACT This study aimed to characterize metal contaminant concentrations and assess temporal and spatial variability in the main drinking water sources of Cap-Haïtien, Haiti. Water sources from five communities were sampled in two seasons, June (2014) and October (2014), and analysed for a suite of metals. A geographic information system was used to examine the spatial distribution of sampling points. Metal concentrations were below the US Environmental Protection Agency (USEPA) primary drinking water standards. Mean manganese concentrations were comparatively higher in wells (254.5 µg/L), exceeding the USEPA secondary drinking water standard (50 µg/L). Higher mean Mg/Ca and Ba/Ca ratios (range 2.3–3.4) may indicate different interactions between seawater and groundwater throughout the year. Although metal concentrations were within the limits of the USEPA drinking water standards, emerging contaminants, such as manganese, showed concentrations in excess of recommended limits. These metals may interact with background nutritional status with potential implications for growth and development.

Screening for early detection of parkinsonism using a self-administered questionnaire: A cross-sectional epidemiologic study

BACKGROUND Manganese (Mn) is a common component of welding fume. Exposure to Mn fume has been associated with parkinsonism. A simple and reliable screening tool to evaluate Mn exposed workers for neurotoxic injury would have broad occupational health application. METHODS This study investigated 490 occupational welders recruited from a trade union list. Subjects were examined by a movement disorders specialist using the Unified Parkinson Disease Rating Scale motor subsection 3 (UPDRS3). Parkinsonism, intermediate, and normal groups were defined as UPDRS3 score ≥ 15, 6-15, and <6, respectively. Workers completed a health status questionnaire (PDQ39) and a Parkinson disease (PD) Symptoms Questionnaire. Areas under receiver operator curve (AUC) were analyzed based on these scores, adjusted for age, smoking, race, gender, and neurologist, using normal as the reference. RESULTS The AUC was 0.79 (95% confidence interval [CI]=0.73-0.84) for PDQ39 and 0.78 (95% CI=0.72-0.85) for PD Symptoms Questionnaire score. At 70% sensitivity, the specificity for PDQ39 score and PD Symptoms Questionnaire score for the prediction of parkinsonism was 73.1% and 80.1%, respectively. CONCLUSIONS These results suggest the questionnaires have reasonably good sensitivity and specificity to predict parkinsonism in Mn exposed workers. These questionnaires could be a valuable first step in a tiered screening approach for Mn exposed workers.

Increased risk of Parkinsonism associated with cumulative hours of welding

Objectives Manganese, an established neurotoxicant, is a common component of welding fumes. Symptoms of manganese poisoning include parkinsonism (PS). Prior epidemiologic evidence regarding occupational welding and PS is mixed, and remains highly controversial. Methods This study investigated the prevalence of PS among 581 active male shipyard welders recruited from a trade union. Study subjects were examined by a movement disorders specialist using the Unified Parkinsons disease Rating Scale motor subsection 3 (UPDRS3) without knowledge of exposure. PS cases were defined as welders with UPDRS3 score ≥15; this threshold corresponds to the degree of motor impairment found in early, symptomatic Parkinsons disease. An intermediate group was defined as UPDRS3 score 6–15. Normal was defined as UPDRS3 <6. Exposure was classified as cumulative hours of welding (“welding hours”), based on validated questionnaire data. Prevalence ratios (PR) for PS, adjusted for age, race, smoking, and education, were calculated in relation to quartiles of welding hours. Results The overall prevalence estimate of PS was 13.1%. We observed a monotonic exposure-response gradient comparing PS cases with normal subjects (UPDRS3<6). PRs (95% CI) for increasing exposure quartiles were: 1.0 (reference), 1.2 (0.6–2.6), 1.4 (0.7–2.8), and 1.6 (0.8–3.1) (p-trend=0.28). There was a much weaker gradient comparing the intermediate UPDRS3 group and normal subjects: 1.0 (reference), 1.0 (0.7–1.3), 1.2 (0.9–1.6), and 1.2 (0.8–1.6) (p-trend=0.11), respectively. Conclusions Results from our ongoing epidemiological study of welders support an etiologic relation of welding exposure and PS. Further work will include a non-welding reference group, and will quantify exposure to manganese.