Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-12 (of 12 Records) |
Query Trace: Bowman JD[original query] |
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Occupational exposure to high-frequency electromagnetic fields and brain tumor risk in the INTEROCC study: An individualized assessment approach
Vila J , Turner MC , Gracia-Lavedan E , Figuerola J , Bowman JD , Kincl L , Richardson L , Benke G , Hours M , Krewski D , McLean D , Parent ME , Sadetzki S , Schlaefer K , Schlehofer B , Schuz J , Siemiatycki J , van Tongeren M , Cardis E . Environ Int 2018 119 353-365 INTRODUCTION: In 2011, the International Agency for Research on Cancer classified radiofrequency (RF) electromagnetic fields (EMF) as possibly carcinogenic to humans (group 2B), although the epidemiological evidence for the association between occupational exposure to RF-EMF and cancer was judged to be inadequate, due in part to limitations in exposure assessment. This study examines the relation between occupational RF and intermediate frequency (IF) EMF exposure and brain tumor (glioma and meningioma) risk in the INTEROCC multinational population-based case-control study (with nearly 4000 cases and over 5000 controls), using a novel exposure assessment approach. METHODS: Individual indices of cumulative exposure to RF and IF-EMF (overall and in specific exposure time windows) were assigned to study participants using a source-exposure matrix and detailed interview data on work with or nearby EMF sources. Conditional logistic regression was used to investigate associations with glioma and meningioma risk. RESULTS: Overall, around 10% of study participants were exposed to RF while only 1% were exposed to IF-EMF. There was no clear evidence for a positive association between RF or IF-EMF and the brain tumors studied, with most results showing either no association or odds ratios (ORs) below 1.0. The largest adjusted ORs were obtained for cumulative exposure to RF magnetic fields (as A/m-years) in the highest exposed category (>/=90th percentile) for the most recent exposure time window (1-4 years before the diagnosis or reference date) for both glioma, OR=1.62 (95% confidence interval (CI): 0.86, 3.01) and meningioma (OR=1.52, 95% CI: 0.65, 3.55). CONCLUSION: Despite the improved exposure assessment approach used in this study, no clear associations were identified. However, the results obtained for recent exposure to RF electric and magnetic fields are suggestive of a potential role in brain tumor promotion/progression and should be further investigated. |
Interactions between occupational exposure to extremely low frequency magnetic fields and chemicals for brain tumour risk in the INTEROCC study
Turner MC , Benke G , Bowman JD , Figuerola J , Fleming S , Hours M , Kincl L , Krewski D , McLean D , Parent ME , Richardson L , Sadetzki S , Schlaefer K , Schlehofer B , Schuz J , Siemiatycki J , Tongeren MV , Cardis E . Occup Environ Med 2017 74 (11) 802-809 OBJECTIVES: In absence of clear evidence regarding possible effects of occupational chemical exposures on brain tumour aetiology, it is worthwhile to explore the hypothesis that such exposures might act on brain tumour risk in interaction with occupational exposure to extremely low frequency magnetic fields (ELF). METHODS: INTEROCC is a seven-country (Australia, Canada, France, Germany, Israel, New Zealand and UK), population-based, case-control study, based on the larger INTERPHONE study. Incident cases of primary glioma and meningioma were ascertained from 2000 to 2004. Job titles were coded into standard international occupational classifications and estimates of ELF and chemical exposures were assigned based on job-exposure matrices. Dichotomous indicators of cumulative ELF (≥50th vs <50th percentile, 1-4 year exposure time window) and chemical exposures (ever vs never, 5-year lag) were created. Interaction was assessed on both the additive and multiplicative scales. RESULTS: A total of 1939 glioma cases, 1822 meningioma cases and 5404 controls were included in the analysis, using conditional logistic regression. There was no clear evidence for interactions between ELF and any of the chemical exposures assessed for either glioma or meningioma risk. For glioma, subjects in the low ELF/metal exposed group had a lower risk than would be predicted from marginal effects. Results were similar according to different exposure time windows, to cut-points of exposure or in exposed-only analyses. CONCLUSIONS: There was no clear evidence for interactions between occupational ELF and chemical exposures in relation to glioma or meningioma risk observed. Further research with more refined estimates of occupational exposures is recommended. |
Berkson error adjustment and other exposure surrogates in occupational case-control studies, with application to the Canadian INTEROCC study
Oraby T , Sivaganesan S , Bowman JD , Kincl L , Richardson L , McBride M , Siemiatycki J , Cardis E , Krewski D . J Expo Sci Environ Epidemiol 2017 28 (3) 251-258 Many epidemiological studies assessing the relationship between exposure and disease are carried out without data on individual exposures. When this barrier is encountered in occupational studies, the subject exposures are often evaluated with a job-exposure matrix (JEM), which consists of mean exposure for occupational categories measured on a comparable group of workers. One of the objectives of the seven-country case-control study of occupational exposure and brain cancer risk, INTEROCC, was to investigate the relationship of occupational exposure to electromagnetic fields (EMF) in different frequency ranges and brain cancer risk. In this paper, we use the Canadian data from INTEROCC to estimate the odds of developing brain tumours due to occupational exposure to EMF. The first step was to find the best EMF exposure surrogate among the arithmetic mean, the geometric mean, and the mean of log-normal exposure distribution for each occupation in the JEM, in comparison to Berkson error adjustments via numerical approximation of the likelihood function. Contrary to previous studies of Berkson errors in JEMs, we found that the geometric mean was the best exposure surrogate. This analysis provided no evidence that cumulative lifetime exposure to extremely low frequency magnetic fields increases brain cancer risk, a finding consistent with other recent epidemiological studies.Journal of Exposure Science and Environmental Epidemiology advance online publication, 29 March 2017; doi:10.1038/jes.2017.2. |
Development of a source-exposure matrix for occupational exposure assessment of electromagnetic fields in the INTEROCC study
Vila J , Bowman JD , Figuerola J , Morina D , Kincl L , Richardson L , Cardis E . J Expo Sci Environ Epidemiol 2016 27 (4) 398-408 To estimate occupational exposures to electromagnetic fields (EMF) for the INTEROCC study, a database of source-based measurements extracted from published and unpublished literature resources had been previously constructed. The aim of the current work was to summarize these measurements into a source-exposure matrix (SEM), accounting for their quality and relevance. A novel methodology for combining available measurements was developed, based on order statistics and log-normal distribution characteristics. Arithmetic and geometric means, and estimates of variability and maximum exposure were calculated by EMF source, frequency band and dosimetry type. The mean estimates were weighted by our confidence in the pooled measurements. The SEM contains confidence-weighted mean and maximum estimates for 312 EMF exposure sources (from 0 Hz to 300 GHz). Operator position geometric mean electric field levels for radiofrequency (RF) sources ranged between 0.8 V/m (plasma etcher) and 320 V/m (RF sealer), while magnetic fields ranged from 0.02 A/m (speed radar) to 0.6 A/m (microwave heating). For extremely low frequency sources, electric fields ranged between 0.2 V/m (electric forklift) and 11,700 V/m (high-voltage transmission line-hotsticks), whereas magnetic fields ranged between 0.14 muT (visual display terminals) and 17 muT (tungsten inert gas welding). The methodology developed allowed the construction of the first EMF-SEM and may be used to summarize similar exposure data for other physical or chemical agents. |
A source-based measurement database for occupational exposure assessment of electromagnetic fields in the INTEROCC study: a literature review approach
Vila J , Bowman JD , Richardson L , Kincl L , Conover DL , McLean D , Mann S , Vecchia P , van Tongeren M , Cardis E . Ann Occup Hyg 2015 60 (2) 184-204 INTRODUCTION: To date, occupational exposure assessment of electromagnetic fields (EMF) has relied on occupation-based measurements and exposure estimates. However, misclassification due to between-worker variability remains an unsolved challenge. A source-based approach, supported by detailed subject data on determinants of exposure, may allow for a more individualized exposure assessment. Detailed information on the use of occupational sources of exposure to EMF was collected as part of the INTERPHONE-INTEROCC study. To support a source-based exposure assessment effort within this study, this work aimed to construct a measurement database for the occupational sources of EMF exposure identified, assembling available measurements from the scientific literature. METHODS: First, a comprehensive literature search was performed for published and unpublished documents containing exposure measurements for the EMF sources identified, a priori as well as from answers of study subjects. Then, the measurements identified were assessed for quality and relevance to the study objectives. Finally, the measurements selected and complementary information were compiled into an Occupational Exposure Measurement Database (OEMD). RESULTS: Currently, the OEMD contains 1624 sets of measurements (>3000 entries) for 285 sources of EMF exposure, organized by frequency band (0 Hz to 300 GHz) and dosimetry type. Ninety-five documents were selected from the literature (almost 35% of them are unpublished technical reports), containing measurements which were considered informative and valid for our purpose. Measurement data and complementary information collected from these documents came from 16 different countries and cover the time period between 1974 and 2013. CONCLUSION: We have constructed a database with measurements and complementary information for the most common sources of exposure to EMF in the workplace, based on the responses to the INTERPHONE-INTEROCC study questionnaire. This database covers the entire EMF frequency range and represents the most comprehensive resource of information on occupational EMF exposure. It is available at www.crealradiation.com/index.php/en/databases. |
Occupational exposure to extremely low frequency magnetic fields and brain tumour risks in the INTEROCC study
Turner MC , Benke G , Bowman JD , Figuerola J , Fleming S , Hours M , Kincl L , Krewski D , McLean D , Parent ME , Richardson L , Sadetzki S , Schlaefer K , Schlehofer B , Schuz J , Siemiatycki J , Van Tongeren M , Cardis E . Cancer Epidemiol Biomarkers Prev 2014 23 (9) 1863-72 BACKGROUND: Occupational exposure to extremely low frequency magnetic fields (ELF) is a suspected risk factor for brain tumours, however the literature is inconsistent. Few studies have assessed whether ELF in different time windows of exposure may be associated with specific histologic types of brain tumours. This study examines the association between ELF and brain tumours in the large-scale INTEROCC study. METHODS: Cases of adult primary glioma and meningioma were recruited in seven countries (Australia, Canada, France, Germany, Israel, New Zealand, United Kingdom) between 2000 and 2004. Estimates of mean workday ELF exposure based on a job exposure matrix assigned. Estimates of cumulative exposure, average exposure, maximum exposure, and exposure duration were calculated for the lifetime, and 1-4, 5-9, and 10+ years prior to the diagnosis/reference date. RESULTS: There were 3,761 included brain tumour cases (1,939 glioma, 1,822 meningioma) and 5,404 population controls. There was no association between lifetime cumulative ELF exposure and glioma or meningioma risk. However, there were positive associations between cumulative ELF 1-4 years prior to the diagnosis/reference date and glioma (odds ratio (OR) ≥ 90th percentile vs < 25th percentile = 1.67, 95% confidence interval (CI) 1.36-2.07, p < 0.0001 linear trend), and, somewhat weaker associations with meningioma (OR ≥ 90th percentile vs < 25th percentile = 1.23, 95% CI 0.97-1.57, p = 0.02 linear trend). CONCLUSIONS: Results showed positive associations between ELF in the recent past and glioma. IMPACT: Occupational ELF exposure may play a role in the later stages (promotion and progression) of brain tumourigenesis. |
Possible health benefits from reducing occupational magnetic fields
Bowman JD , Ray TK , Park RM . Am J Ind Med 2013 56 (7) 791-805 BACKGROUND: Magnetic fields (MF) from AC electricity are a Possible Human Carcinogen, based on limited epidemiologic evidence from exposures far below occupational health limits. METHODS: To help formulate government guidance on occupational MF, the cancer cases prevented and the monetary benefits accruing to society by reducing workplace exposures were determined. Life-table methods produced Disability Adjusted Life Years, which were converted to monetary values. RESULTS: Adjusted for probabilities of causality, the expected increase in a worker's disability-free life are 0.04 year (2 weeks) from a 1 microtesla (microT) MF reduction in average worklife exposure, which is equivalent to $5,100/worker/microT in year 2010 U.S. dollars (95% confidence interval $1,000-$9,000/worker/microT). Where nine electrosteel workers had 13.8 microT exposures, for example, moving them to ambient MFs would provide $600,000 in benefits to society (uncertainty interval $0-$1,000,000). CONCLUSIONS: When combined with the costs of controls, this analysis provides guidance for precautionary recommendations for managing occupational MF exposures. |
Electric shocks at work in Europe: development of a job exposure matrix
Huss A , Vermeulen R , Bowman JD , Kheifets L , Kromhout H . Occup Environ Med 2013 70 (4) 261-7 OBJECTIVES: Electric shocks have been suggested as a potential risk factor for neurological disease, in particular for amyotrophic lateral sclerosis. While actual exposure to shocks is difficult to measure, occurrence and variation of electric injuries could serve as an exposure proxy. We assessed risk of electric injury, using occupational accident registries across Europe to develop an electric shock job-exposure-matrix (JEM). MATERIALS AND METHODS: Injury data were obtained from five European countries, and the number of workers per occupation and country from EUROSTAT was compiled at a 3-digit International Standard Classification of Occupations 1988 level. We pooled accident rates across countries with a random effects model and categorised jobs into low, medium and high risk based on the 75th and 90th percentile. We next compared our JEM to a JEM that classified extremely low frequency magnetic field exposure of jobs into low, medium and high. RESULTS: Of 116 job codes, occupations with high potential for electric injury exposure were electrical and electronic equipment mechanics and fitters, building frame workers and finishers, machinery mechanics and fitters, metal moulders and welders, assemblers, mining and construction labourers, metal-products machine operators, ships' decks crews and power production and related plant operators. Agreement between the electrical injury and magnetic field JEM was 67.2%. CONCLUSIONS: Our JEM classifies occupational titles according to risk of electric injury as a proxy for occurrence of electric shocks. In addition to assessing risk potentially arising from electric shocks, this JEM might contribute to disentangling risks from electric injury from those of extremely low frequency magnetic field exposure. |
Evaluation of occupational exposure to magnetic fields and motor neuron disease mortality in a population-based cohort
Parlett LE , Bowman JD , van Wijngaarden E . J Occup Environ Med 2011 53 (12) 1447-51 OBJECTIVE: Epidemiologic evidence for the association between electromagnetic fields and amyotrophic lateral sclerosis, the most common form of motor neuron disease (MND), has been inconclusive. We evaluated the association between electromagnetic fields and MND among workers in occupations potentially exposed to magnetic fields. METHODS: MND mortality (ICD-9 335.2) was examined in the National Longitudinal Mortality Study using multivariable proportional hazards models. Occupational exposure to magnetic fields was determined on the basis of a population-based job-exposure matrix. Age at entry, education, race, sex, and income were considered for inclusion as covariates. RESULTS: After adjusting for age, sex, and education, there were no increased risks of MND mortality in relation to potential magnetic field exposure, with hazard ratios around the null in all magnetic field exposure quartiles. CONCLUSIONS: Our study does not provide evidence for an association between magnetic field exposure and MND mortality. |
Risk of brain tumours in relation to estimated RF dose from mobile phones: results from five Interphone countries
Cardis E , Armstrong BK , Bowman JD , Giles GG , Hours M , Krewski D , McBride M , Parent ME , Sadetzki S , Woodward A , Brown J , Chetrit A , Figuerola J , Hoffmann C , Jarus-Hakak A , Montestruq L , Nadon L , Richardson L , Villegas R , Vrijheid M . Occup Environ Med 2011 68 (9) 631-40 OBJECTIVES: The objective of this study was to examine the associations of brain tumours with radio frequency (RF) fields from mobile phones. METHODS: Patients with brain tumour from the Australian, Canadian, French, Israeli and New Zealand components of the Interphone Study, whose tumours were localised by neuroradiologists, were analysed. Controls were matched on age, sex and region and allocated the 'tumour location' of their matched case. Analyses included 553 glioma and 676 meningioma cases and 1762 and 1911 controls, respectively. RF dose was estimated as total cumulative specific energy (TCSE; J/kg) absorbed at the tumour's estimated centre taking into account multiple RF exposure determinants. RESULTS: ORs with ever having been a regular mobile phone user were 0.93 (95% CI 0.73 to 1.18) for glioma and 0.80 (95% CI 0.66 to 0.96) for meningioma. ORs for glioma were below 1 in the first four quintiles of TCSE but above 1 in the highest quintile, 1.35 (95% CI 0.96 to 1.90). The OR increased with increasing TCSE 7+ years before diagnosis (p-trend 0.01; OR 1.91, 95% CI 1.05 to 3.47 in the highest quintile). A complementary analysis in which 44 glioma and 135 meningioma cases in the most exposed area of the brain were compared with gliomas and meningiomas located elsewhere in the brain showed increased ORs for tumours in the most exposed part of the brain in those with 10+ years of mobile phone use (OR 2.80, 95% CI 1.13 to 6.94 for glioma). Patterns for meningioma were similar, but ORs were lower, many below 1.0. CONCLUSIONS: There were suggestions of an increased risk of glioma in long-term mobile phone users with high RF exposure and of similar, but apparently much smaller, increases in meningioma risk. The uncertainty of these results requires that they be replicated before a causal interpretation can be made. |
Estimation of RF energy absorbed in the brain from mobile phones in the Interphone Study
Cardis E , Varsier N , Bowman JD , Deltour I , Figuerola J , Mann S , Moissonnier M , Taki M , Vecchia P , Villegas R , Vrijheid M , Wake K , Wiart J . Occup Environ Med 2011 68 (9) 686-93 OBJECTIVES: The objective of this study was to develop an estimate of a radio frequency (RF) dose as the amount of mobile phone RF energy absorbed at the location of a brain tumour, for use in the Interphone Epidemiological Study. METHODS: We systematically evaluated and quantified all the main parameters thought to influence the amount of specific RF energy absorbed in the brain from mobile telephone use. For this, we identified the likely important determinants of RF specific energy absorption rate during protocol and questionnaire design, we collected information from study subjects, network operators and laboratories involved in specific energy absorption rate measurements and we studied potential modifiers of phone output through the use of software-modified phones. Data collected were analysed to assess the relative importance of the different factors, leading to the development of an algorithm to evaluate the total cumulative specific RF energy (in joules per kilogram), or dose, absorbed at a particular location in the brain. This algorithm was applied to Interphone Study subjects in five countries. RESULTS: The main determinants of total cumulative specific RF energy from mobile phones were communication system and frequency band, location in the brain and amount and duration of mobile phone use. Though there was substantial agreement between categorisation of subjects by cumulative specific RF energy and cumulative call time, misclassification was non-negligible, particularly at higher frequency bands. Factors such as adaptive power control (except in Code Division Multiple Access networks), discontinuous transmission and conditions of phone use were found to have a relatively minor influence on total cumulative specific RF energy. CONCLUSIONS: While amount and duration of use are important determinants of RF dose in the brain, their impact can be substantially modified by communication system, frequency band and location in the brain. It is important to take these into account in analyses of risk of brain tumours from RF exposure from mobile phones. |
Analyzing digital vector waveforms of 0-3000 Hz magnetic fields for health studies
Bowman JD , Miller CK , Krieg EF , Song R . Bioelectromagnetics 2010 31 (5) 391-405 To improve the assessment of magnetic field exposures for occupational health studies, the Multiwave(R) System III (MW3) was developed to capture personal exposures to the three-dimensional magnetic field vector B(t) in the 0-3000 Hz band. To process hundreds of full-shift MW3 measurements from epidemiologic studies, new computer programs were developed to calculate the magnetic field's physical properties and its interaction with biological systems through various mechanisms (magnetic induction, radical pair interactions, ion resonance, etc.). For automated calculations in the frequency domain, the software uses new algorithms that remove artifacts in the magnetic field's Fourier transform due to electronic noise and the person's motion through perturbations in the geomagnetic field from steel objects. These algorithms correctly removed the Fourier transform artifacts in 92% of samples and have improved the accuracy of frequency-dependent metrics by as much as 3300%. The output of the MwBatch software is a matrix of 41 exposure metrics calculated for each 2/15 s sample combined with 8 summary metrics for the person's full-period exposure, giving 294 summary-exposure metrics for each person monitored. In addition, the MwVisualizer software graphically explores the magnetic field's vector trace, its component waveforms, and the metrics over time. The output was validated against spreadsheet calculations with pilot data. This software successfully analyzed full-shift MW3 monitoring with 507 electric utility workers, comprising over 1 million vector waveforms. The software's output can be used to test hypotheses about magnetic field biology and disease with biophysical models and also assess compliance with exposure limits. Bioelectromagnetics, 2010. (c) 2010 Wiley-Liss, Inc. |
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