An Ecological Evaluation of Vinyl Chloride Exposure and Liver Cancer Incidence and Mortality in Texas.

The goal of this analysis was to evaluate the association between county-level ambient vinyl chloride (VC) and county-level liver cancer incidence and mortality rates in Texas. Modeled county-level ambient VC data were obtained from the National Air Toxics Assessment. Age-adjusted county-level liver cancer incidence rates were abstracted from the Texas Cancer Registry and age-standardized county-level liver cancer mortality rates were obtained from the peer-reviewed literature. Multivariable imputation was utilized to impute incidence rates in counties with suppressed liver cancer incidence rates. Negative binomial and Poisson regression models were utilized to evaluate the association between county-level ambient VC and county-level liver cancer incidence and mortality rates, respectively, adjusted for county-level heavy drinking prevalence, hepatitis mortality rates, median income, and race (percent Hispanic). County-level ambient VC was not associated with county-level liver cancer incidence or mortality rates. Specifically, when compared to the lowest tertile of ambient VC, the middle (relative risk [RR]: 1.06, 95% confidence interval [CI]: 0.95-1.19) and highest (RR: 1.03, 95% CI: 0.90-1.17) tertiles of ambient VC were not associated with liver cancer incidence. Similarly, county-level ambient VC in the middle (RR: 0.95, 95% CI: 0.85-1.05) and highest (RR: 0.93, 95% CI: 0.82-1.05) tertiles were not associated with liver cancer mortality. This analysis suggests that county-level ambient VC is not associated with liver cancer incidence or mortality in Texas. Our study provides novel results regarding liver cancer risk from low-level non-occupational exposure to ambient VC.

Systematic review and meta-analysis of epidemiological literature evaluating the association between exposure to man-made vitreous fibers and respiratory tract cancers.

We conducted a systematic review and meta-analysis of epidemiological studies that evaluated occupational exposure to man-made vitreous fibers (MMVF) including glass, rock, and slag wools, and respiratory tract cancers (RTC) including cancers of the larynx, trachea, bronchus, and lung. The MEDLINE/PubMed and Web of Science databases were searched in order to identify epidemiological studies that evaluated the association between occupational MMVF exposure and RTCs. We performed random-effects meta-analyses of relevant studies identified by our literature search, and evaluated sources of between-study heterogeneity. The pooled relative risk (RR) of RTC among workers exposed to MMVFs was 1.09 (95% CI = 0.97, 1.22). The RR was closer to 1.0 when limiting the analysis to effect estimates from studies that accounted for the main a priori risk factors for RTC, asbestos exposure and smoking (RR = 1.03, 95% CI = 0.90, 1.18). Overall, our synthesis of the epidemiological literature suggests that occupational MMVF exposure is not associated with risk of RTC.

Evaluation of Personal Exposure to Surgical Smoke Generated from Electrocautery Instruments: A Pilot Study.

Hospital technician surgical smoke exposures during several types of electrocautery-based procedures were evaluated. Personal and area air sampling was performed for 106 individual analytes including ultrafine particulate matter (UFP), volatile organic compounds, polycyclic aromatic hydrocarbons, phenol, aldehydes, carbon monoxide, hydrogen sulfide, and hydrogen cyanide. Acetone, d-limonene, ethanol, ethyl acetate, and fluorene were measured in surgical suites at concentrations 1.1- to 3.7-fold higher than those observed in background. Benzene, α-pinene, methylene chloride, and n-hexane were measured in the absence of a detectable background concentration. All analytes were measured at concentrations that were <1% of the corresponding US federal and state 8-h permissible exposure limits (PELs), if PELs existed. Full-shift average UFP concentrations ranged from 773 to 2257 particles/cm3, approximately one order of magnitude higher than surgical suite background concentrations. A comparison of two breast reduction procedures suggested that the use of smoke evacuators reduced UFP exposure by 6-fold. We concluded that selection and evaluation of key hazards, particularly UFP, under a variety of experimental conditions would be beneficial to elucidate potential health effects and causes osf employee complaints. Recommendations for successful sampling campaigns in future surgical smoke occupational exposure studies are provided. We also recommend the continued use of engineering controls, local exhaust ventilation, and surgical N95 respirators to reduce personal exposures to UFP in surgical smoke.

Occupational exposures to cosmetic talc and risk of mesothelioma: an updated pooled cohort and statistical power analysis with consideration of latency period.

Objectives: We previously published a pooled statistical power analysis of mesothelioma incidence in the Italian, Norwegian, Austrian, and French cosmetic talc miner and miller cohorts. Soon thereafter, updates to the Italian and Norwegian cohorts were published, providing an additional 14,322 person-years of observation. In this study, we provide an updated power analysis using the newly available information. Methods: We pooled the current results regarding pleural cancer/mesothelioma mortality or incidence in four cosmetic talc miner and miller cohorts in Italy, Norway, Austria, and France. We used the expected numbers of cases as reported by the authors and the power analysis was based on an a priori one-sided significance level of 0.05 and Poisson distribution probabilities. Results: There was a pooled total of 113,344 person-years in the cohorts. Although 3.0 pleural cancers/mesotheliomas were expected, there were no reported pleural cancer or mesothelioma cases in any cohort. Our pooled analysis was associated with 79 and 62% power to detect a 3.0-fold and 2.5-fold or greater increase in pleural cancer/mesothelioma, respectively. These favorable power characteristics were effectively maintained when restricting the pooled cohort to workers with a latency period of 30 or more years (observation time from first employment). Conclusions: The epidemiological evidence from the cosmetic talc miner/miller cohort studies does not support the hypothesis that exposure to cosmetic talc is associated with the development of pleural cancer/mesothelioma.

Ethylene oxide and risk of lympho-hematopoietic cancer and breast cancer: a systematic literature review and meta-analysis.

PURPOSE: To conduct a systematic literature review and meta-analysis of studies of lympho-hematopoietic cancers (LHC) and breast cancer risk among persons occupationally exposed to ethylene oxide (EO). METHODS: We performed a literature search for articles available in PubMed and Web of Science databases to identify literature and subsequently systematically searched the reference lists of identified studies, published review papers and meta-analyses, as well as relevant government or regulatory documents. We qualitatively reviewed 30 studies and conducted meta-analyses on 13 studies. Pooled risk estimates were calculated using random effects models, stratifying by occupational group, cancer type and decade of publication. RESULTS: The overall meta-relative risks (meta-RRs) for LHC and breast cancer, respectively, were 1.48 (95% CI 1.07-2.05) and 0.97 (95% CI 0.80-1.18). The meta-RR's for LHC among EO production and EO sterilization workers were 1.46 (95% CI 0.85-2.50) and 1.07 (95% CI 0.87-1.30), respectively. We observed higher risks of LHC in the earlier published studies, compared to the later studies, and the meta-RR's for the 1980s, 1990s, 2000s, and the 2010s, respectively, were 3.87 (95% CI 1.87-8.01), 1.38 (95% CI 0.85-2.25), 1.05 (95% CI 0.84-1.31), and 1.19 (95% CI 0.80-1.77). CONCLUSIONS: The most informative epidemiology studies, which were published in the 2000s and 2010s, do not support the conclusion that exposure to EO is associated with an increased risk of LHC or breast cancer.

The 2014 crude 4-methylcyclohexanemethanol chemical release and birth outcomes in West Virginia.

Approximately 10,000 gallons of crude 4-methylcyclohexanemethanol and propylene glycol phenyl ether were accidentally released into the Elk River upstream from a water treatment facility in West Virginia. The objective of this study was to use logistic and Poisson regression analyses to determine the effect potential exposures had on adverse birth outcomes (birth weight, small for gestational age, and abnormal Apgar score). We adjusted for confounding factors and assessed prevalence of adverse birth outcomes by residential location and timing of the pregnancy. There were no statistically significant interactions between residential location and timing of the pregnancy (range of p values: .157-.806). Changes in the prevalence of birth outcomes were consistent before and after the spill regardless of residential location. There was no evidence of an association between adverse birth outcomes and potential exposure to the released chemicals.

Non-occupational exposure to asbestos and risk of pleural mesothelioma: review and meta-analysis.

OBJECTIVE: To conduct an updated literature review and meta-analysis of studies of pleural malignant mesothelioma (PMM) risk among persons exposed to asbestos non-occupationally (household and neighbourhood). METHODS: We performed a literature search for articles available in the National Center for Biotechnology Information's PubMed database published between 1967 and 2016. Meta-analyses were conducted to calculate pooled PMM risk estimates, stratifying for household or neighbourhood exposure to asbestos and/or predominant asbestos fibre type (chrysotile, amphibole or mixed). RESULTS: Eighteen studies in 12 countries comprising 665 cases met the meta-analysis inclusion criteria. We identified 13 estimates of PMM risk from neighbourhood exposures, 10 from household and one from mixed exposure, and combined the estimates using random-effects models. The overall meta-relative risk (meta-RR) was 5.9 (95% CI 4.4 to 8.7). The meta-RRs for household and neighbourhood exposures were 5.4 (95% CI 2.6 to 11.2) and 6.9 (95% CI 4.2 to 11.4), respectively. We observed trends in risk in relation to fibre type for both household and neighbourhood studies. For chrysotile, mixed and amphibole fibres, respectively, meta-RRs for neighbourhood studies were 3.8 (95% CI 0.4 to 38.4), 8.4 (95% CI 4.7 to 14.9) and 21.1 (95% CI 5.3 to 84.5) and meta-RRs for household studies were 4.0 (95% CI 0.8 to 18.8), 5.3 (95% CI 1.9 to 15.0) and 21.1 (95% CI 2.8 to 156.0). CONCLUSIONS: PMM risks from non-occupational asbestos exposure are consistent with the fibre-type potency response observed in occupational settings. By relating our findings to knowledge of exposure-response relationships in occupational settings, we can better evaluate PMM risks in communities with ambient asbestos exposures from industrial or other sources.

Cosmetic talc as a risk factor for pleural mesothelioma: a weight of evidence evaluation of the epidemiology.

OBJECTIVE: Due to some historical (and inaccurate) reports that asbestos might be present in some cosmetic talc products, questions are occasionally raised regarding the potential pleural mesothelioma risks associated with cosmetic talc products. Our objective was to determine the incidence of pleural mesothelioma of individuals exposed to cosmetic talc. MATERIALS AND METHODS: We conducted a systematic review of the epidemiological literature for cosmetic talc miners and millers and found three occupational cohort studies that evaluated pleural mesothelioma incidence in workers in Italy, Norway, France, and Austria. We conducted a second literature review to evaluate the incidence and mortality of pleural mesothelioma among patients who received talc pleurodesis treatments before 1965 and found retrospective clinical studies including over 300 patients with follow-up ranging from 14 to 40 years. RESULTS: There were no mesotheliomas reported in any of the cosmetic talc miner and miller cohorts. A pooled analysis of data from the cohort mortality studies indicated that four mesothelioma deaths would have been expected from the 90,022 person-years of observation, and this was associated with 84% and 67% statistical power to observe a 3-fold or 2.5-fold increase in pleural mesothelioma mortality, respectively. None of the patients who received talc pleurodesis treatments developed mesothelioma. CONCLUSION: We conclude that there is no epidemiological evidence to support the hypothesis that exposure to cosmetic talc is associated with the development of pleural mesothelioma.

Environmental lead and childhood blood lead levels in US children: NHANES, 1999-2006.

Although blood lead levels in the United States have fallen dramatically since 1980, there remain subgroups of children with high blood lead levels. We assessed the relationship between environmental lead sources and blood lead levels in children ages 1 to 5 years from the National Health and Nutrition Examination Survey (NHANES), 1999-2006. Modeled ambient air lead levels and industrial lead releases at the census-tract level were assigned to each child's residence with adjustment for confounding factors. Of 3,223 children, 272 (8.4%) had blood lead levels ≥ 5 ug/dL. Industrial releases (2,252 vs 1,696 lbs/mi2) and ambient air lead levels (2.28 vs 1.75 ng/m3) were greater in exposed versus unexposed children. For every 10,000 lb/mi2 increase in inverse distance squared weighted exposure, there was a 1.13% increase (95% CI: 0.45%, 1.81%) in blood lead (p = .001).

Evaluation of reported fatality data associated with workers using respiratory protection in the United States (1990-2012).

OSHA revised the 1971 respiratory protection standard in 1998 to add guidance for selecting and maintaining respirators. Fatality reports from 1990 to 2012 were used to characterize historical trends in fatalities associated with respirators. Industry- and time-specific trends were evaluated to determine the effect of the revision to the standard on respirator-related fatalities; 174 respirator-related deaths were reported. The majority of fatalities were associated with using an airline respirator (n = 34) or the absence of using a respirator in required spaces (n = 38). Overall, 79% of fatalities were associated with asphyxia. Fatalities were associated with improper employee use or lack of employer compliance. Reductions in fatality rates over time appeared to be associated with the revisions to the respirator standard, although other variables may influence rates (eg, controls). Recommendations for employers and employees regarding maintaining safe use of respirators are provided.

Can 8-hydroxy-2'-deoxyguanosine be used to assess oxidative stress caused by particulate matter air pollution in the general population?

OBJECTIVES: Assess the association between 8-hydroxy-2'-deoxyguanosine (8OHdG) levels and particulate matter air pollution in non-occupational exposure groups from peer-reviewed literature. METHODS: Ovid Medline and PubMed were used to search for all peer-reviewed articles published between 1946 and May 2013. Keywords included particulate matter, air pollution, deoxyguanosine, 8-hydroxy-2'-deoxyguanosine, and known abbreviations. Seven English, non-occupational exposure, human subject studies were evaluated. RESULTS: Of the two studies involving children one found significant positive associations between exposure to particulate matter air pollution and 8OHdG. Investigations into non-occupationally exposed adults were mixed. The lone double-blind crossover study found no relationship between diesel exhaust exposure and 8OHdG. Two out of three panel studies and one cohort study found significant associations between 8OHdG and classes of particles and for various lags. CONCLUSIONS: Analyses accounting for particle composition and lags between exposure and physiological responses had the strongest significant associations. Results are not conclusive due to the inconsistency in study designs, small sample sizes, and differences in exposure assessment techniques. Consistent methodology with representative populations including women and other non-occupationally exposed groups are recommended.

Flat fold and cup-shaped N95 filtering facepiece respirator face seal area and pressure determinations: a stereophotogrammetry study.

Twenty subjects underwent quantitative respirator fit testing with two styles (flat fold, cup-shaped) of N95 filtering facepiece respirators (N95 FFRs). Passing a fit test was followed by stereophotogrammetry to determine the face seal area and computation of seal pressure. There were significantly different seal pressures (p < 0.01) between standard size flat fold and cup-shaped N95 FFRs but no significant differences in face seal area. No significant differences were noted in fit factors, but more individuals passed fit testing wearing flat fold respirators. The ability of flat fold N95 FFRs, at lower seal pressures, to obtain similar fit factors as cup-shaped N95 FFR at higher seal pressures offers the possibility of enhanced facial comfort without a loss of protection. Stereophotogrammetry offers a relatively simple, non-invasive technology to evaluate various properties of N95 FFR fit.

Trends in acute myocardial infarction hospitalization rates for US States in the CDC tracking network.

OBJECTIVES: We examined temporal trends, spatial variation, and gender differences in rates of hospitalization due to acute myocardial infarction. METHODS: We used data from the Centers for Disease Control National Environmental Public Health Tracking Network to evaluate temporal trends, geographic variation, and gender differences in 20 Environmental Public Health Tracking Network states from 2000 to 2008. A longitudinal linear mixed effects model was fitted to the acute myocardial infarction hospitalization rates for the states and counties within each state to examine the overall temporal trend. RESULTS: There was a significant overall decrease in age-adjusted acute myocardial infarction hospitalization rates between 2000 and 2008, with most states showing over a 20% decline during the period. The ratio of male/female rates for acute myocardial infarction hospitalization rates remained relatively consistent over time, approximately two-fold higher in men compared to women. A large geographic variability was found for age-adjusted acute myocardial infarction hospitalization rates, with the highest rates found in the Northeastern states. Results of two ecological analyses revealed that the NE region remained significantly associated with increased AMI hospitalization rates after adjustment for socio-demographic factors. CONCLUSIONS: This investigation is one of the first to explore geographic differences in AMI age adjusted hospital rates in individuals 35+ years of age for 2000-2008. We showed a decreasing trend in AMI hospitalization rates in men and women. A large geographic variability in rates was found with particularly higher rates in the New England/Mid-Atlantic region of the US and lower rates in the mountain and Pacific states of the tracking network. It appeared that over time this disparity in rates became less notable.

Proper use of surgical n95 respirators and surgical masks in the OR.

Proper adherence to infection control precautions, including appropriate selection and use of personal protective equipment (PPE), is of significant importance to the health and well-being of perioperative personnel. Surgical masks are intended for use as a barrier to protect the wearer's face from large droplets and splashes of blood and other body fluids; however, surgical and high-filtration surgical laser masks do not provide enough protection to be considered respiratory PPE. Potential exposure to airborne contaminants and infectious agents, including those present in surgical smoke, necessitates the use of respiratory PPE, such as a surgical N95 particulate filtering facepiece respirator. Filtering facepiece respirators greatly reduce a wide size range of particles from entering the wearer's breathing zone and are designed to protect the user from both droplet and airborne particles. Every health care worker who must use a respirator to control hazardous exposures in the workplace must be trained to properly use the respirator and pass a fit test before using it in the workplace.

Pulmonary and heart rate responses to wearing N95 filtering facepiece respirators.

BACKGROUND: Filtering facepiece respirators are the most common respirator worn by US health care and industrial workers, yet little is known on the physiologic impact of wearing this protective equipment. METHODS: Twenty young, healthy subjects exercised on a treadmill at a low-moderate (5.6 km/h) work rate while wearing 4 different models of N95 filtering facepiece respirators for 1 hour each, 2 models of which were equipped with exhalation valves, while being monitored for physiologic variables. RESULTS: Compared with controls, respirator use was associated with mean 1 hour increases in heart rate (range, 5.7-10.6 beats per minute, P < .001), respiratory rate (range, 1.4-2.4 breaths per minute, P < .05), and transcutaneous carbon dioxide (range, 1.7-3.0 mm Hg, P < .001). No significant differences in oxygen saturation between controls and respirators were noted (P > .05). CONCLUSION: The pulmonary and heart rate responses to wearing a filtering facepiece respirator for 1 hour at a low-moderate work rate are relatively small and should generally be well tolerated by healthy persons.

Absence of consequential changes in physiological, thermal and subjective responses from wearing a surgical mask.

Twenty subjects treadmill exercised at 5.6 km/h for 1h with and without wearing a surgical mask while being monitored for heart rate, respiratory rate, oxygen saturation, transcutaneous CO2, SpO2, core and skin temperatures, mask deadspace heat and relative humidity, and skin temperature under the mask. Rating scales were utilized for exertion and heat perceptions. Surgical mask use resulted in increases in heart rate (9.5 beats/min; p<0.001), respiratory rate (1.6 breaths/min; p=0.02), and transcutaneous carbon dioxide (2.17 mmHg; p=0.0006), and decreased temperature of uncovered facial skin (0.40 °C; p=0.03). The 1.76 °C increase in temperature of the skin covered by the mask was associated with a mask deadspace apparent heat index of 52.9 °C. Perceptions of heat were neutral to slightly hot, and for exertion ranged from very, very light to fairly light. Surgical mask use for 1h at a low-moderate work rate is not associated with clinically significant physiological impact or significant subjective perceptions of exertion or heat.