Pauline Slottje

Utrecht University, Utrecht, Utrecht, Netherlands

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Publications (45)162.06 Total impact

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    ABSTRACT: Previous experimental studies on electromagnetic hypersensitivity have been criticized regarding inflexibility of choice of exposure and of study locations. We developed and tested novel portable exposure units that can generate different output levels of various extremely low frequency magnetic fields (ELF-MF; 50 Hz field plus harmonics) and radiofrequency electromagnetic fields (RF-EMF). Testing was done with a group of healthy volunteers (n = 25 for 5 ELF-MF and n = 25 for 5 RF-EMF signals) to assess if units were indeed able to produce double-blind exposure conditions. Results substantiated that double-blind conditions were met; on average participants scored 50.6% of conditions correct on the ELF-MF, and 50.0% on the RF-EMF unit, which corresponds to guessing probability. No cues as to exposure conditions were reported. We aim to use these units in a future experiment with subjects who wish to test their personal hypothesis of being able to sense or experience when being exposed to EMF. The new units allow for a high degree of flexibility regarding choice of applied electromagnetic signal, output power level and location (at home or another environment of subjects' choosing). Bioelectromagnetics. 2015;9999:1-7. © 2015 Wiley Periodicals, Inc.
    No preview · Article · Dec 2015 · Bioelectromagnetics
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    ABSTRACT: Objective To investigate the latent structure of somatic symptom reports in the general population with a bi-factor model and apply the structure to the analysis of change in reported symptoms after the emergence of an uncertain environmental health risk. Methods Somatic symptoms were assessed in two general population environmental health cohorts (AMIGO, n = 14,829 & POWER, n = 951) using the somatization scale of the four-dimensional symptom questionnaire (4DSQ-S). Exploratory bi-factor analysis was used to determine the factor structure in the AMIGO cohort. Multi-group and longitudinal models were applied to assess measurement invariance. For a subsample of residents living close to a newly introduced power line (n = 224), we compared a uni- and multidimensional method for the analysis of change in reported symptoms after the power line was put into operation. Results We found a good fit (RMSEA = 0.03, CFI = 0.98) for a bi-factor model with one general and three symptom specific factors (musculoskeletal, gastrointestinal, cardiopulmonary). The latent structure was found to be invariant between cohorts and over time. A significant increase (p < .05) was found only for musculoskeletal and gastrointestinal symptoms after the power line was put into operation. Conclusions In our study we found that a bi-factor structure of somatic symptoms reports was equivalent between cohorts and over time. Our findings suggest that taking this structure into account can lead to a more informative interpretation of a change in symptom reports compared to a unidimensional approach.
    Full-text · Article · Sep 2015 · Journal of Psychosomatic Research
  • Suzan Bongers · Pauline Slottje · Lützen Portengen · Hans Kromhout
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    ABSTRACT: To study the association between occupational MRI-related static magnetic fields (SMF) exposure and the occurrence of accidents. Recent and career SMF exposure was assessed by linking a retrospective job exposure matrix to payroll based job histories, for a cohort of (former) workers of an imaging device manufacturing facility in the Netherlands. Occurrence of accidents was collected through an online questionnaire. Self-reported injuries due to accidents in the past 12 months, and the first (near) traffic accident while commuting to work and from work were analyzed with logistic regression and discrete-time survival analyses, respectively. High recent SMF exposure was associated with an increased risk of accidents leading to injuries [odds ratio (OR) 4.16]. For high recent and career SMF exposure, an increased risk was observed for accidents resulting in physician-treated injuries (OR 5.78 and 2.79, respectively) and an increased lifetime risk of (near) accidents during commute to work (hazard ratios 2.49 and 2.45, respectively), but not from work. We found an association between MRI-related occupational SMF exposure and an increased risk of accidents leading to injury, and for commute-related (near) accidents during the commute from home to work. Further research into health effects of (long-term) SMF exposure is warranted to corroborate our findings. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    No preview · Article · Jun 2015 · Magnetic Resonance in Medicine
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    ABSTRACT: We studied the association between occupational exposure to extremely low-frequency magnetic fields (ELF-MF) and electrical shocks and acute myeloid leukemia (AML) in the Nordic Occupational Cancer cohort (NOCCA). We included 5,409 adult AML cases diagnosed between 1961 and 2005 in Finland, Iceland, Norway, and Sweden and 27,045 controls matched by age, sex, and country. Lifetime occupational ELF-MF exposure and risk of electrical shocks were assigned to jobs reported in the censuses using job-exposure matrices. We estimated hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) using conditional logistic regression adjusted for concurrent occupational exposures relevant for AML risk (e.g., benzene, ionizing radiation). We conducted sensitivity analyses with different assumptions to assess the robustness of our results. Approximately 40 % of the subjects were ever occupationally exposed to low levels and 7 % to high levels of ELF-MF, whereas 18 % were ever at low risk and 15 % at high risk of electrical shocks. We did not observe an association between occupational exposure to neither ELF-MF nor electrical shocks and AML. The HR was 0.88 (95 % CI 0.77-1.01) for subjects with high levels of ELF-MF exposure and 0.94 (95 % CI 0.85-1.05) for subjects with high risk of electrical shocks as compared to those with background-level exposure. Results remained materially unchanged in sensitivity analyses with different assumptions. Our results do not support an association between occupational ELF-MF or electric shock exposure and AML.
    Full-text · Article · May 2015 · Cancer Causes and Control
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    ABSTRACT: Occupational exposures may be associated with non-vascular dementia. We analyzed the effects of occupational exposures to solvents, pesticides, metals, extremely low frequency magnetic fields (ELF-MF), electrical shocks, and diesel motor exhaust on non-vascular dementia related mortality in the Netherlands Cohort Study (NLCS). Exposures were assigned using job-exposure matrices. After 17.3 years of follow-up, 682 male and 870 female cases were available. Analyses were performed using Cox regression. Occupational exposure to metals, chlorinated solvents and ELF-MF showed positive associations with non-vascular dementia among men, which seemed driven by metals (hazard ratio ever high vs. background exposure: 1.35 [0.98-1.86]). Pesticide exposure showed statistically significant, inverse associations with non-vascular dementia among men. We found no associations for shocks, aromatic solvents, and diesel motor exhaust. Consistent positive associations were found between occupational exposure to metals and non-vascular dementia. The finding on pesticides is not supported in the overall literature. Am. J. Ind. Med. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    No preview · Article · May 2015 · American Journal of Industrial Medicine
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    ABSTRACT: To determine whether the use of quantitative personal exposure measurements in experimental research would result in better estimates of the associations between static and time-varying magnetic field exposure and neurocognitive test performance than when exposure categories were based solely on distance to the magnetic field source. In our original analysis, based on distance to the magnet of a 7 T MRI scanner, an effect of exposure to static magnetic fields was observed. We performed a sensitivity analysis of test performance on a reaction task and line bisection task with different exposure measures that were derived from personal real-time measurements. The exposure measures were highly comparable, and almost all models resulted in significant associations between exposure to time-varying magnetic fields within a static magnetic field and performance on a reaction and line bisection task. In a controlled experimental setup, distance to the bore is a good proxy for personal exposure when placing subjects at fixed positions with standardized head movements in the magnetic stray fields of a 7 T MRI. Use of a magnetic field dosimeter is, however, important for estimating quantitative exposure response associations. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
    No preview · Article · Feb 2015 · Magnetic Resonance in Medicine
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    ABSTRACT: Occupational and environmental exposures remain important modifiable risk factors of public health. Existing cohort studies are often limited by the level of detail of data collected on these factors and health. It is also often assumed that the more healthy group is over-represented in cohort studies, which is of concern for their external validity. In this cohort profile, we describe how we set up the population-based Occupational and Environmental Health Cohort Study (AMIGO) to longitudinally study occupational and environmental determinants of diseases and well-being from a multidisciplinary and life course point of view. Reviewed by the Medical Ethics Research Committee of the University Medical Center Utrecht (protocol 10-268/C). All cohort members participate voluntarily and gave informed consent prior to their inclusion. 14 829 adult cohort members (16% of those invited) consented and filled in the online baseline questionnaire. Determinants include chemical, biological, physical (eg, electromagnetic fields), and psychosocial factors. Priority health outcomes include cancer, neurological, cardiovascular and respiratory diseases and non-specific symptoms. Owing to the recruitment strategy via general practitioners of an established network, we also collect longitudinal data registered in their electronic medical records including symptoms, diagnosis and treatments. Besides the advantage of health outcomes that cannot be easily captured longitudinally by other means, this created a unique opportunity to assess health-related participation bias by comparing general practitioner-registered prevalence rates in the cohort and its source population. We found no indications of such a systematic bias. The major assets of the AMIGO approach are its detailed occupational and environmental determinants in combination with the longitudinal health data registered in general practice besides linkage to cancer and mortality registries and self-reported health. We are now in the phase of prospective follow-up, with the aim of continuing this for as long as possible (20+ years), pending future funding. Findings will be disseminated through scientific conferences and peer-reviewed journals, and through newsletters and the project website to participants, stakeholders and the wider public. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Full-text · Article · Nov 2014 · BMJ Open
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    ABSTRACT: PurposeThis experimental study aims to separate neurocognitive effects resulting from exposure to static magnetic stray fields (SMF) alone and the combination of SMF and low-frequency movement-induced time-varying magnetic fields (TVMF) using a 7 Tesla (T) MRI scanner in stand-by mode.Methods In a double-blind randomized crossover experiment, 36 healthy volunteers underwent four sessions, two exposed conditions, and two corresponding sham conditions. The exposure conditions were in front of the scanner bore and consisted of 1.0 T SMF with or without 2.4 T/s TVMF, induced by standardized head movements before each of the five neurocognitive tasks. These specific tasks were selected because previous experiments showed negative effects of SMF + TVMF exposure on test performance.ResultsExposure to SMF in combination with TVMF decreased verbal memory performance significantly and changed visual acuity. Similarly, attention and concentration were negatively affected with borderline significance. Exposure to SMF only did not have significant effects on the performance on any of the tasks.Conclusion Neurocognitive effects were only observed when simultaneously exposed to SMF and TVMF from a 7 T MRI scanner. Therefore, exposure to TVMF seems essential in eliciting the neurocognitive effects in our present study and, presumably, previous experiments. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
    No preview · Article · Sep 2014 · Magnetic Resonance in Medicine
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    ABSTRACT: Objectives Movement in the magnetic fields around MRI systems showed acute negative effects on concentration, memory, visuo-spatial orientation and postural body sway. A crucial role of the vestibular system has been hypothesised. We aimed to gain more insight whether subjects with a relatively (un)sensitive vestibular system performed differently on cognitive tasks when (moving) in a the static magnetic field of an MRI scanner. Method In a double blind randomised cross over experiment 36 healthy volunteers underwent several cognitive tasks in 4 experimental sessions. Two were exposure conditions near a 7 Tesla (T) MRI system with personal exposure of 1.0 T. In one of these conditions additional time-varying magnetic fields of 2.4 T/s were induced by making standardised head movements. Of the two sham conditions (0 T) one was with and the other without such head movements. Vestibular sensitivity of each subject was assessed by the rotary chair test, the caloric reflex test and self-reported sensitivity to motion sickness. Results Linear mixed models are currently in progress to test cognitive performance in a magnetic field for subjects with a low, normal and high sensitive vestibular organ. Preliminary results seem to suggest some differential cognitive effects of magnetic field exposure according to relative vestibular sensitivity. Further results will be presented at the conference. Conclusions These findings are important to better understand a possible working mechanism evoking these cognitive effects. Moreover, these finding can form a basis for the design of relevant protective and precautionary control measures for employees working close to an MRI system.
    No preview · Article · Jun 2014 · Occupational and Environmental Medicine
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    ABSTRACT: To evaluate the association between occupational exposure to extremely low frequency magnetic fields (ELF-MF) or electric shocks and brain cancer, haemopoietic and lymphatic malignancies, and breast cancer incidence in the Nordic Occupational Cancer cohort.
    No preview · Article · Jun 2014 · Occupational and Environmental Medicine
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    ABSTRACT: Evidence for the carcinogenicity of shift work in humans is limited because of significant heterogeneity of the results, thus more in-depth research in needed. The Nightingale Study is a nationwide prospective cohort study on occupational exposures and risks of chronic diseases among female nurses and focuses on the potential association between shift work and risk of breast cancer. The study design, methods, and baseline characteristics of the cohort are described. The source population for the cohort comprised 18 to 65 year old women who were registered as having completed training to be a nurse in the nationwide register for healthcare professionals in the Netherlands. Eligible women were invited to complete a web-based questionnaire including full job history, a detailed section on all domains of shift work (shift system, cumulative exposure, and shift intensity) and potential confounding factors, and an informed consent form for linkage with national (disease) registries. Women were also asked to donate toenail clippings as a source of DNA for genetic analyses. Between October 6, 2011 and February 1, 2012, 31% of the 192,931 women who were invited to participate completed the questionnaire, yielding a sample size of 59,947 cohort members. The mean age of the participants was 46.9 year (standard deviation 11.0 years). Toenail clippings were provided by 23,439 participants (39%). Results from the Nightingale Study will contribute to the scientific evidence of potential shift work-related health risks among nurses and will help develop preventive measures and policy aimed at reducing these risks.
    Full-text · Article · Jan 2014 · BMC Cancer
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    ABSTRACT: To investigate the association between exposure to occupational extremely low-frequency magnetic fields (ELF-MF) and the risk of a priori selected cancer outcomes within the prospective Netherlands Cohort Study. 120,852 men and women aged 55-69 years at time of enrollment in 1986 were followed up (17.3 years) for incident lung, breast and brain cancer, and hemato-lymphoproliferative malignancies. Information on occupational history and potential confounders such as sex, age, smoking, alcohol use, and attained educational level were collected at baseline through a self-administered questionnaire. Occupational ELF-MF exposure was assigned with a job-exposure matrix. Using a case-cohort approach, associations with cancer incidence were analyzed with Cox regression stratified by sex, using three exposure metrics: (1) ever had a job with low or high exposure to ELF-MF versus background, (2) duration of exposure, and (3) cumulative exposure. None of the exposure metrics showed an effect on incidence for lung, breast, and brain cancer, nor any of the assessed subtypes in men and women. Of the hemato-lymphoproliferative malignancies in men, ever high exposed to ELF-MF showed a significant association with acute myeloid leukemia (AML) [hazard ratio (HR) 2.15; 95 % confidence interval (CI) 1.06-4.35] and follicular lymphoma (FL) (HR 2.78; 95 % CI 1.00-5.77). Cumulative exposure to ELF-MF showed a significant, positive association with FL but not AML among men. In this large prospective cohort study, we found some indications of an increased risk of AML and FL among men with occupational ELF-MF exposure. These findings warrant further investigation.
    No preview · Article · Nov 2013 · Cancer Causes and Control
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    ABSTRACT: At present, the relationship between chronic exposure to static magnetic fields (SMF) and health effects is unclear. We developed a task-based deterministic model for estimating historical electromagnetic field exposure from the static B-field (B0) of magnetic resonance imaging (MRI) systems, for a cohort of employees working at an MRI systems development and production facility. Technical maps describing the spatial distribution of fringe fields of B0 surrounding different types of MRI systems of various core strengths were exploited to derive estimates of static B0 exposure as a function of distance from the bore of the MRI system. Detailed information on tasks performed per exposed job and other model determinants were acquired through face-to-face interviews and used to derive base estimates of most recent exposure (2009) for each job title. The model was partially validated with actual exposure measurements. The exposure estimates from the deterministic model were used to construct a job-exposure matrix that will enable estimation of cumulative exposures for each cohort member. The generic approach described for estimating chronic MRI-related SMF exposure makes it universally applicable in other studies investigating health effects of MRI-related SMF exposure.
    No preview · Article · Sep 2013 · Annals of Occupational Hygiene
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    ABSTRACT: This study aims to characterise and quantify the population that is occupationally exposed to electromagnetic fields (EMF) from magnetic resonance imaging (MRI) devices and to identify factors that determine the probability and type of exposure. A questionnaire survey was used to collect information about scanners, procedures, historical developments and employees working with or near MRI scanners in clinical and research MRI departments in the Netherlands. Data were obtained from 145 MRI departments. A rapid increase in the use of MRI and field strength of the scanners was observed and quantified. The strongest magnets were employed by academic hospitals and research departments. Approximately 7000 individuals were reported to be working inside an MRI scanner room and were thus considered to have high probability of occupational exposure to static magnetic fields (SMF). Fifty-four per cent was exposed to SMF at least one day per month. The largest occupationally exposed group were radiographers (n∼1700). Nine per cent of the 7000 involved workers were regularly present inside a scanner room during image acquisition, when exposure to additional types of EMF is considered a possibility. This practice was most prevalent among workers involved in scanning animals. The data illustrate recent trends and historical developments in magnetic resonance imaging and provide an extensive characterisation of the occupationally exposed population. A considerable number of workers are potentially exposed to MRI-related EMF. Type and frequency of potential exposure depend on the job performed, as well as the type of workplace.
    Full-text · Article · Aug 2013 · European journal of radiology
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    ABSTRACT: We assessed postural body sway performance after exposure to movement induced time-varying magnetic fields in the static magnetic stray field in front of a 7 Tesla (T) magnetic resonance imaging scanner. Using a double blind randomized crossover design, 30 healthy volunteers performed two balance tasks (i.e., standing with eyes closed and feet in parallel and then in tandem position) after standardized head movements in a sham, low exposure (on average 0.24 T static magnetic stray field and 0.49 T·s(-1) time-varying magnetic field) and high exposure condition (0.37 T and 0.70 T·s(-1) ). Personal exposure to static magnetic stray fields and time-varying magnetic fields was measured with a personal dosimeter. Postural body sway was expressed in sway path, area, and velocity. Mixed-effects model regression analysis showed that postural body sway in the parallel task was negatively affected (P < 0.05) by exposure on all three measures. The tandem task revealed the same trend, but did not reach statistical significance. Further studies are needed to investigate the possibility of independent or synergetic effects of static magnetic stray field and time-varying magnetic field exposure. In addition, practical safety implications of these findings, e.g., for surgeons and others working near magnetic resonance imaging scanners need to be investigated. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
    No preview · Article · Jul 2013 · Magnetic Resonance in Medicine
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    ABSTRACT: Objectives: Although a study among utility workers found an increased risk for acute myocardial infarction and arrhythmia-related deaths associated with occupational extremely low-frequency magnetic fields (ELF-MF) exposure, later studies largely failed to replicate these findings. This study investigated the association between occupational ELF-MF exposure and cardiovascular disease (CVD) mortality within a community-based prospective cohort study. Methods: The Netherlands Cohort Study is a prospective cohort study among 120 852 men and women aged 55-69 years at baseline. Participants were followed-up for CVD mortality over a period of 10 years, resulting in 8200 CVD deaths. Information on occupational history and potential confounders, such as educational level, smoking and alcohol use were collected at baseline through a self-administered questionnaire. Occupational ELF-MF exposure was assigned using a job-exposure matrix. Associations with CVD mortality were analysed using Cox regression. Results: Ever low or high exposure to ELF-MF showed no association with total CVD mortality (HR of 1.02, 95% CI 0.99 to 1.06), nor with any cause-specific subtypes of CVD mortality. Other ELF-MF exposure metrics showed no increased risks either. Conclusions: In this study, we found no indication of an association between occupational ELF-MF exposure and risk of CVD mortality.
    No preview · Article · Jan 2013 · Occupational and environmental medicine
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    ABSTRACT: This study characterises neurocognitive domains that are affected by movement-induced time-varying magnetic fields (TVMF) within a static magnetic stray field (SMF) of a 7 Tesla (T) MRI scanner. Using a double-blind randomised crossover design, 31 healthy volunteers were tested in a sham (0 T), low (0.5 T) and high (1.0 T) SMF exposure condition. Standardised head movements were made before every neurocognitive task to induce TVMF. Of the six tested neurocognitive domains, we demonstrated that attention and concentration were negatively affected when exposed to TVMF within an SMF (varying from 5.0% to 21.1% per Tesla exposure, p<0.05), particular in situations were high working memory performance was required. In addition, visuospatial orientation was affected after exposure (46.7% per Tesla exposure, p=0.05). Neurocognitive functioning is modulated when exposed to movement-induced TVMF within an SMF of a 7 T MRI scanner. Domains that were affected include attention/concentration and visuospatial orientation. Further studies are needed to better understand the mechanisms and possible practical safety and health implications of these acute neurocognitive effects.
    No preview · Article · Aug 2012 · Occupational and environmental medicine
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    ABSTRACT: Background: In epidemiological studies, occupational exposure estimates are often assigned through linkage of job histories to job-exposure matrices (JEMs). However, available JEMs may have a coding system incompatible with the coding system used to code the job histories, necessitating a translation of the originally assigned job codes. Since manual recoding is usually not feasible in large studies, this is often done by use of automated crosswalks translating job codes from one system to another. We set out to investigate whether automatically translating job codes led to different exposure estimates compared with those resulting from manual recoding using the original job descriptions. Methods: One hundred job histories were randomly drawn from the Netherlands Cohort Study on diet and cancer (NLCS), using a sampling strategy designed to oversample potentially exposed jobs. This resulted in 220 job codes that were automatically translated from the original Dutch coding system to the International Standard Classification of Occupations (ISCO)-68 and ISCO-88 as well as manually recoded from the job descriptions in the original questionnaire by two coders. Exposure to several agents (i.e. chromium, asbestos, silica, pesticides, aromatic solvents, and extremely low-frequency magnetic fields) was assigned by JEMs based on job codes resulting from automatic and manual recodings. Results: The agreement between occupational exposure estimates based on the crosswalk versus those based on manual recoding reached a Cohen's Kappa (κ) of 0.66 or higher and were similar to the agreements between the two coders. Conclusions: Results of this study indicate that using automated crosswalks to recode job codes from one occupational classification system to another results only in a limited loss in agreement in assigned occupational exposure estimates compared with direct manual recoding. Therefore, in this case, crosswalks provide an efficient alternative to the costly and time-consuming direct manual recoding from job history descriptions from questionnaires.
    No preview · Article · Jul 2012 · Annals of Occupational Hygiene

  • No preview · Article · Oct 2011 · Occupational and Environmental Medicine

  • No preview · Article · Oct 2011 · Occupational and Environmental Medicine

Publication Stats

560 Citations
162.06 Total Impact Points

Institutions

  • 2009-2015
    • Utrecht University
      • • Division of Environmental Epidemiology
      • • Institute for Risk Assessment Sciences (IRAS)
      Utrecht, Utrecht, Netherlands
    • National Institute for Public Health and the Environment (RIVM)
      Utrecht, Utrecht, Netherlands
  • 2005-2015
    • VU University Amsterdam
      • Department of Public and Occupational Health
      Amsterdamo, North Holland, Netherlands
  • 2014
    • Netherlands Institute for Space Research, Utrecht
      Utrecht, Utrecht, Netherlands
  • 2010
    • Institute for Health and Care Research
      Amsterdamo, North Holland, Netherlands
  • 2005-2008
    • VU University Medical Center
      • Department of Public and Occupational Health
      Amsterdamo, North Holland, Netherlands