Last data update: Jun 17, 2024. (Total: 47034 publications since 2009)
Records 1-12 (of 12 Records) |
Query Trace: Welder L [original query] |
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Suicidal thoughts and behaviors among high school students - Youth Risk Behavior Survey, United States, 2021
Gaylor EM , Krause KH , Welder LE , Cooper AC , Ashley C , Mack KA , Crosby AE , Trinh E , Ivey-Stephenson AZ , Whittle L . MMWR Suppl 2023 72 (1) 45-54 Suicide is the third leading cause of death among high school-aged youths aged 14-18 years. The 2021 suicide rate for this age group was 9.0 per 100,000 population. Updating a previous analysis of the Youth Risk Behavior Survey during 2009-2019, this report uses 2019 and 2021 data to examine high school students' reports of suicidal thoughts and behaviors. Prevalence estimates are reported by grade, race and ethnicity, sexual identity, and sex of sexual contacts. Unadjusted logistic regression models were used to calculate prevalence differences comparing 2019 to 2021 and prevalence ratios comparing suicidal behavior between subgroups across demographic characteristics to a referent group. From 2019 to 2021, female students had an increased prevalence of seriously considered attempting suicide (from 24.1% to 30%), an increase in making a suicide plan (from 19.9% to 23.6%), and an increase in suicide attempts (from 11.0% to 13.3%). In addition, from 2019 to 2021, Black or African American (Black), Hispanic or Latino (Hispanic), and White female students had an increased prevalence of seriously considered attempting suicide. In 2021, Black female students had an increased prevalence of suicide attempts and Hispanic female students had an increased prevalence of suicide attempts that required medical treatment compared with White female students. Prevalence of suicidal thoughts and behaviors remained stable overall for male students from 2019 to 2021. A comprehensive approach to suicide prevention with a focus on health equity is needed to address these disparities and reduce prevalence of suicidal thoughts and behaviors for all youths. School and community-based strategies include creating safe and supportive environments, promoting connectedness, teaching coping and problem solving, and gatekeeper training. |
Parental monitoring and risk behaviors and experiences among high school students - Youth Risk Behavior Survey, United States, 2021
Dittus PJ , Li J , Verlenden JV , Wilkins NJ , Carman-McClanahan MN , Cavalier Y , Mercado MC , Welder LE , Roehler DR , Ethier KA . MMWR Suppl 2023 72 (1) 37-44 Parents have an important role in the promotion of healthy adolescent behaviors that can influence positive developmental trajectories and health outcomes. Parental monitoring is a central component of the parent-child relationship with the potential to reduce adolescent risk behaviors. Data from CDC's 2021 nationally representative Youth Risk Behavior Survey were used to describe the prevalence of parental monitoring reported by U.S. high school students and examine associations between parental monitoring and adolescent behaviors and experiences. Behaviors and experiences included sexual behaviors, substance use, violence, and indicators of poor mental health. This report marks the first national assessment of parental monitoring among U.S. high school students. Point prevalence estimates and corresponding 95% CIs were generated in the bivariate analyses between parental monitoring and the outcomes, stratified by demographic characteristics (sex, race and ethnicity, sexual identity, and grade). Multivariable logistic regression analyses were conducted to estimate the main effects of parental monitoring (categorized as high = always or most of the time and low = never, rarely, or sometimes) for each outcome, controlling for all demographics. Overall, 86.4% of students reported that their parents or other adults in their family know where they are going or with whom they will be all or most of the time. Reports of high parental monitoring were protective for all risk behaviors and experiences, with models controlling for sex, race and ethnicity, sexual identity, and grade. Results highlight the need for public health professionals who develop public health interventions and programs to conduct further research on the relation between parental monitoring and student health outcomes. |
Suicides among American Indian or Alaska Native Persons - National Violent Death Reporting System, United States, 2015-2020
Stone D , Trinh E , Zhou H , Welder L , End Of Horn P , Fowler K , Ivey-Stephenson A . MMWR Morb Mortal Wkly Rep 2022 71 (37) 1161-1168 Compared with the general U.S. population, American Indian or Alaska Native (AI/AN) persons, particularly those who are not Hispanic or Latino (Hispanic) AI/AN, are disproportionately affected by suicide; rates among this group consistently surpass those among all other racial and ethnic groups (1). Suicide rates among non-Hispanic AI/AN persons increased nearly 20% from 2015 (20.0 per 100,000) to 2020 (23.9), compared with a <1% increase among the overall U.S. population (13.3 and 13.5, respectively) (1). Understanding characteristics of suicide among AI/AN persons is critical to developing and implementing effective prevention strategies. A 2018 report described suicides in 18 states among non-Hispanic AI/AN persons only (2). The current study used 2015-2020 National Violent Death Reporting System (NVDRS) data among 49 states, Puerto Rico, and the District of Columbia to examine differences in suicide characteristics and contributing circumstances among Hispanic and non-Hispanic AI/AN populations, including multiracial AI/AN. Results indicated higher odds across a range of circumstances, including 10 of 14 relationship problems (adjusted odds ratio [aOR] range = 1.2-3.8; 95% CI range = 1.0-5.3) and six of seven substance use problems (aOR range = 1.2-2.3; 95% CI range = 1.1-2.5), compared with non-AI/AN persons. Conversely, AI/AN decedents had reduced odds of having any current known mental health condition, any history of mental health or substance use treatment, and other common risk factors (aOR range = 0.6-0.8; 95% CI = 0.2-0.9). Suicide is preventable. Communities can implement a comprehensive public health approach to suicide prevention that addresses long-standing inequities affecting AI/AN populations (3). |
Strains Associated with Two 2020 Welder Anthrax Cases in the United States Belong to Separate Lineages within Bacillus cereus sensu lato.
Carroll LM , Marston CK , Kolton CB , Gulvik CA , Gee JE , Weiner ZP , Kovac J . Pathogens 2022 11 (8) ![]() Anthrax-causing members of Bacillus cereus sensu lato (s.l.) pose a serious threat to public health. While most anthrax-causing strains resemble B. anthracis phenotypically, rare cases of anthrax-like illness caused by strains resembling "B. cereus" have been reported. Here, whole-genome sequencing was used to characterize three B. cereus s.l. isolates associated with two 2020 welder anthrax cases in the United States, which resembled "B. cereus" phenotypically. Comparison of the three genomes sequenced here to all publicly available, high-quality B. cereus s.l. genomes (n = 2890 total genomes) demonstrated that genomes associated with each case effectively belonged to separate species at the conventional 95% average nucleotide identity prokaryotic species threshold. Two PubMLST sequence type 78 (ST78) genomes affiliated with a case in Louisiana were most closely related to B. tropicus and possessed genes encoding the Bps exopolysaccharide capsule, as well as hemolysin BL (Hbl) and cytotoxin K (CytK). Comparatively, a ST108 genome associated with a case in Texas was most closely related to B. anthracis; however, like other anthrax-causing strains most closely related to B. anthracis, this genome did not possess Bps-, Hbl-, or CytK-encoding genes. Overall, results presented here provide insights into the evolution of anthrax-causing B. cereus s.l. |
Manganese and neurobehavioral impairment. A preliminary risk assessment
Park RM , Berg SL . Neurotoxicology 2017 64 159-165 Similar patterns of cognitive and motor deficits have been widely reported from manganese exposures in welding, metallurgical and chemical industry workers. A risk assessment was performed based on studies reported in the literature, extending some earlier work, and deriving new estimates of exposure response and excess risk. Many investigations of manganese neurological effects in humans have insufficient information to derive an exposure response; however, findings from a chemical manufacturer, two smelter and two welder populations permitted application of the benchmark dose procedure for continuous end-points. Small particles and aggregates of condensation fume (condensing vaporized metal, < 0.1mum in diameter) appear to have a higher potency per unit mass than larger particles from dusts (> 1.0mum). Consideration was given to long-term effects of continuous low exposures that instead of producing increasing toxicity attain a steady-state condition. Impairment was defined as excursions beyond the 5th percentile in a normal population and the concentrations of manganese predicted to result in 1% excess prevalence of impairment over different time periods were calculated. Over five years, exposures resulting in 1% excess prevalence of impairment (for purposes of discussion) were in the vicinity of 10mug/m3 for manganese fume and 25mug/m3 for larger particle dusts. These levels are below current recommendations for occupational limits on manganese exposure in the United States. |
Evolution of welding-fume aerosols with time and distance from the source: a study was conducted on the spatiotemporal variability in welding-fume concentrations for the characterization of first- and second-hand exposure to welding fumes
Cena LG , Chen BT , Keane MJ . Weld J 2016 95 280s-285s Gas metal arc welding fumes were generated from mild-steel plates and measured near the arc (30 cm), representing first-hand exposure of the welder, and farther away from the source (200 cm), representing second-hand exposure of adjacent workers. Measurements were taken during 1-min welding runs and at subsequent 5-min intervals after the welding process was stopped. Number size distributions were measured in real time. Particle mass distributions were measured using a micro-orifice uniform deposition impactor, and total mass concentrations were measured with polytetrafluorothylene filters. Membrane filters were used for collecting morphology samples for electron microscopy. Average mass concentrations measured near the arc were 45 mg/m3 and 9 mg/m3 at the farther distance. The discrepancy in concentrations at the two distances was attributed to the presence of spatter particles, which were observed only in the morphology samples near the source. As fumes aged over time, mass concentrations at the farther distance decreased by 31% (6.2 mg/m3) after 5 min and an additional 13% (5.4 mg/m3) after 10 min. Particle number and mass distributions during active welding were similar at both distances, indicating similar exposure patterns for welders and adjacent workers. Exceptions were recorded for particles smaller than 50 nm and larger than 3 mum, where concentrations were higher near the arc, indicating higher exposures of welders. These results were confirmed by microscopy analysis. As residence time increased, number concentrations decreased dramatically. In terms of particle number concentrations, second-hand exposures to welding fumes during active welding may be as high as first-hand exposures. |
Development and characterization of a resistance spot welding aerosol generator and inhalation exposure system
Afshari A , Zeidler-Erdely PC , McKinney W , Chen BT , Jackson M , Schwegler-Berry D , Friend S , Cumpston A , Cumpston JL , Donny Leonard H , Meighan TG , Frazer DG , Antonini JM . Inhal Toxicol 2014 26 (12) 1-12 Limited information exists regarding the health risks associated with inhaling aerosols that are generated during resistance spot welding of metals treated with adhesives. Toxicology studies evaluating spot welding aerosols are non-existent. A resistance spot welding aerosol generator and inhalation exposure system was developed. The system was designed by directing strips of sheet metal that were treated with an adhesive to two electrodes of a spot welder. Spot welds were made at a specified distance from each other by a computer-controlled welding gun in a fume collection chamber. Different target aerosol concentrations were maintained within the exposure chamber during a 4-h exposure period. In addition, the exposure system was run in two modes, spark and no spark, which resulted in different chemical profiles and particle size distributions. Complex aerosols were produced that contained both metal particulates and volatile organic compounds (VOCs). Size distribution of the particles was multi-modal. The majority of particles were chain-like agglomerates of ultrafine primary particles. The submicron mode of agglomerated particles accounted for the largest portion of particles in terms of particle number. Metal expulsion during spot welding caused the formation of larger, more spherical particles (spatter). These spatter particles appeared in the micron size mode and accounted for the greatest amount of particles in terms of mass. With this system, it is possible to examine potential mechanisms by which spot welding aerosols can affect health, as well as assess which component of the aerosol may be responsible for adverse health outcomes. |
A comparison of cytotoxicity and oxidative stress from welding fumes generated with a new nickel-, copper-based consumable versus mild and stainless steel-based welding in RAW 264.7 mouse macrophages
Badding MA , Fix NR , Antonini JM , Leonard SS . PLoS One 2014 9 (6) e101310 Welding processes that generate fumes containing toxic metals, such as hexavalent chromium (Cr(VI)), manganese (Mn), and nickel (Ni), have been implicated in lung injury, inflammation, and lung tumor promotion in animal models. While federal regulations have reduced permissible worker exposure limits to Cr(VI), this is not always practical considering that welders may work in confined spaces and exhaust ventilation may be ineffective. Thus, there has been a recent initiative to minimize the potentially hazardous components in welding materials by developing new consumables containing much less Cr(VI) and Mn. A new nickel (Ni) and copper (Cu)-based material (Ni-Cu WF) is being suggested as a safer alternative to stainless steel consumables; however, its adverse cellular effects have not been studied. This study compared the cytotoxic effects of the newly developed Ni-Cu WF with two well-characterized welding fumes, collected from gas metal arc welding using mild steel (GMA-MS) or stainless steel (GMA-SS) electrodes. RAW 264.7 mouse macrophages were exposed to the three welding fumes at two doses (50 microg/ml and 250 microg/ml) for up to 24 hours. Cell viability, reactive oxygen species (ROS) production, phagocytic function, and cytokine production were examined. The GMA-MS and GMA-SS samples were found to be more reactive in terms of ROS production compared to the Ni-Cu WF. However, the fumes from this new material were more cytotoxic, inducing cell death and mitochondrial dysfunction at a lower dose. Additionally, pre-treatment with Ni-Cu WF particles impaired the ability of cells to phagocytize E. coli, suggesting macrophage dysfunction. Thus, the toxic cellular responses to welding fumes are largely due to the metal composition. The results also suggest that reducing Cr(VI) and Mn in the generated fume by increasing the concentration of other metals (e.g., Ni, Cu) may not necessarily improve welder safety. |
A novel method for assessing respiratory deposition of welding fume nanoparticles
Cena LG , Keane MJ , Chisholm WP , Stone S , Harper M , Chen BT . J Occup Environ Hyg 2014 11 (12) 771-80 Welders are exposed to high concentrations of nanoparticles. Compared to larger particles, nanoparticles have been associated with more toxic effects at the cellular level, including the generation of more reactive oxygen species activity. Current methods for welding-fume aerosol exposures do not differentiate between the nano-fraction and the larger particles. The objectives of this work are to establish a method to estimate the respiratory deposition of the nano-fraction of selected metals in welding fumes and test this method in a laboratory setting. Manganese (Mn), Nickel (Ni), Chromium (Cr) and hexavalent chromium (Cr(VI)) are commonly found in welding fume aerosols and have been linked with severe adverse health outcomes. Inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography (IC) were evaluated as methods for analyzing the content of Mn, Ni, Cr and Cr(VI) nanoparticles in welding fumes collected with nanoparticle respiratory deposition (NRD) samplers. NRD samplers collect nanoparticles at deposition efficiencies that closely resemble physiological deposition in the respiratory tract. The limits of detection (LODs) and quantitation (LOQs) for ICP-MS and IC were determined analytically. Mild and stainless steel welding fumes generated with a robotic welder were collected with NRD samplers inside a chamber. LODs (LOQs) for Mn, Ni, Cr, and Cr(VI) were 1.3 mug (4.43 mug); 0.4 mug (1.14 mug), 1.1 mug (3.33 mug), and 0.4 mug (1.42 mug), respectively. Recovery of spiked samples and certified welding fume reference material was greater than 95%. When testing the method, the average percentage of total mass concentrations collected by the NRD samplers was approximately 30% for Mn, approximately 50% for Cr and approximately 60% for Ni, indicating that a large fraction of the metals may lay in the nanoparticle fraction. This knowledge is critical to the development of toxicological studies aimed at finding links between exposure to welding fume nanoparticles and adverse health effects. Future work will involve the validation of the method in workplace settings. |
Comparative microscopic study of human and rat lungs after overexposure to welding fume
Antonini JM , Roberts JR , Schwegler-Berry D , Mercer RR . Ann Occup Hyg 2013 57 (9) 1167-79 Welding is a common industrial process used to join metals and generates complex aerosols of potentially hazardous metal fumes and gases. Most long-time welders experience some type of respiratory disorder during their time of employment. The use of animal models and the ability to control the welding fume exposure in toxicology studies have been helpful in developing a better understanding of how welding fumes affect health. There are no studies that have performed a side-by-side comparison of the pulmonary responses from an animal toxicology welding fume study with the lung responses associated with chronic exposure to welding fume by a career welder. In this study, post-mortem lung tissue was donated from a long-time welder with a well-characterized work background and a history of extensive welding fume exposure. To simulate a long-term welding exposure in an animal model, Sprague-Dawley rats were treated once a week for 28 weeks by intratracheal instillation with 2mg of a stainless steel, hard-surfacing welding fume. Lung tissues from the welder and the welding fume-treated rats were examined by light and electron microscopy. Pathological analysis of lung tissue collected from the welder demonstrated inflammatory cell influx and significant pulmonary injury. The poor and deteriorating lung condition observed in the welder examined in this study was likely due to exposure to very high levels of potentially toxic metal fumes and gases for a significant number of years due to work in confined spaces. The lung toxicity profile for the rats treated with welding fume was similar. For tissue samples from both the welder and treated rats, welding particle accumulations deposited and persisted in lung structures and were easily visualized using light microscopic techniques. Agglomerates of deposited welding particles mostly were observed within lung cells, particularly alveolar macrophages. Analysis of individual particles within the agglomerates showed that these particles were metal complexes with iron, chromium, and nickel being the most common metals present. In conclusion, long-term exposure to specific welding fume can lead to serious chronic lung disease characterized by significant particle deposition and persistence as demonstrated in both a human case study and rat model. Not only were the lung responses similar in the human and rat lungs, as evidenced by inflammatory cell influx and pulmonary disease, but the composition of individual welding particles and agglomerations in situ was comparable. |
Immunotoxicology of arc welding fume: worker and experimental animal studies
Zeidler-Erdely PC , Erdely A , Antonini JM . J Immunotoxicol 2012 9 (4) 411-25 Arc welding processes generate complex aerosols composed of potentially hazardous metal fumes and gases. Millions of workers worldwide are exposed to welding aerosols daily. A health effect of welding that is of concern to the occupational health community is the development of immune system dysfunction. Increased severity, frequency, and duration of upper and lower respiratory tract infections have been reported among welders. Specifically, multiple studies have observed an excess mortality from pneumonia in welders and workers exposed to metal fumes. Although several welder cohort and experimental animal studies investigating the adverse effects of welding fume exposure on immune function have been performed, the potential mechanisms responsible for these effects are limited. The objective of this report was to review both human and animal studies that have examined the effect of welding fume pulmonary exposure on local and systemic immune responses. |
Comparison of stainless and mild steel welding fumes in generation of reactive oxygen species
Leonard SS , Chen BT , Stone SG , Schwegler-Berry D , Kenyon AJ , Frazer D , Antonini JM . Part Fibre Toxicol 2010 7 32 BACKGROUND: Welding fumes consist of a wide range of complex metal oxide particles which can be deposited in all regions of the respiratory tract. The welding aerosol is not homogeneous and is generated mostly from the electrode/wire. Over 390,000 welders were reported in the U.S. in 2008 while over 1 million full-time welders were working worldwide. Many health effects are presently under investigation from exposure to welding fumes. Welding fume pulmonary effects have been associated with bronchitis, metal fume fever, cancer and functional changes in the lung. Our investigation focused on the generation of free radicals and reactive oxygen species from stainless and mild steel welding fumes generated by a gas metal arc robotic welder. An inhalation exposure chamber located at NIOSH was used to collect the welding fume particles. RESULTS: Our results show that hydroxyl radicals (.OH) were generated from reactions with H2O2 and after exposure to cells. Catalase reduced the generation of .OH from exposed cells indicating the involvement of H2O2. The welding fume suspension also showed the ability to cause lipid peroxidation, effect O2 consumption, induce H2O2 generation in cells, and cause DNA damage. CONCLUSION: Increase in oxidative damage observed in the cellular exposures correlated well with .OH generation in size and type of welding fumes, indicating the influence of metal type and transition state on radical production as well as associated damage. Our results demonstrate that both types of welding fumes are able to generate ROS and ROS-related damage over a range of particle sizes; however, the stainless steel fumes consistently showed a significantly higher reactivity and radical generation capacity. The chemical composition of the steel had a significant impact on the ROS generation capacity with the stainless steel containing Cr and Ni causing more damage than the mild steel. Our results suggest that welding fumes may cause acute lung injury. Since type of fume generated, particle size, and elapsed time after generation of the welding exposure are significant factors in radical generation and particle deposition these factors should be considered when developing protective strategies. |
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