• Modeled and Perceived Exposure to Radiofrequency Electromagnetic Fields From Mobile-Phone Base Stations and the Development of Symptoms Over Time in a General Population Cohort.

      Martens, Astrid L; Slottje, Pauline; Timmermans, Danielle R M; Kromhout, Hans; Reedijk, Marije; Vermeulen, Roel C H; Smid, Tjabe (2017-07-15)
      We assessed associations between modeled and perceived exposure to radiofrequency electromagnetic fields (RF-EMF) from mobile-phone base stations and the development of nonspecific symptoms and sleep disturbances over time. A population-based Dutch cohort study, the Occupational and Environmental Health Cohort Study (AMIGO) (n = 14,829; ages 31-65 years), was established in 2011/2012 (T0), with follow-up of a subgroup (n = 3,992 invited) in 2013 (T1; n = 2,228) and 2014 (T2; n = 1,740). We modeled far-field RF-EMF exposure from mobile-phone base stations at the home addresses of the participants using a 3-dimensional geospatial model (NISMap). Perceived exposure (0 = not at all; 6 = very much), nonspecific symptoms, and sleep disturbances were assessed by questionnaire. We performed cross-sectional and longitudinal analyses, including fixed-effects regression. We found small correlations between modeled and perceived exposure in AMIGO participants at baseline (n = 14,309; rSpearman = 0.10). For 222 follow-up participants, modeled exposure increased substantially (>0.030 mW/m2) between T0 and T1. This increase in modeled exposure was associated with an increase in perceived exposure during the same time period. In contrast to modeled RF-EMF exposure from mobile-phone base stations, perceived exposure was associated with higher symptom reporting scores in both cross-sectional and longitudinal analyses, as well as with sleep disturbances in cross-sectional analyses.
    • Modeled and perceived RF-EMF, noise and air pollution and symptoms in a population cohort. Is perception key in predicting symptoms?

      Martens, Astrid L; Reedijk, Marije; Smid, Tjabe; Huss, Anke; Timmermans, Danielle; Strak, Maciej; Swart, Wim; Lenters, Virissa; Kromhout, Hans; Verheij, Robert; et al. (2018-05-17)
      Psychosocial research has shown that perceived exposure can influence symptom reporting, regardless of actual exposure. The impact of this phenomenon on the interpretation of results from epidemiological research on environmental determinants of symptoms is unclear.
    • Modeling of soil functions for assessing soil quality: soil biodiversity and habitat provisioning

      van Leeuwen, JP; Creamer, RE; Cluzeau, D; Debeljak, M; Gatti, F; Henriksen, CB; Kuzmanovski, V; Rutgers, M (2019-10-04)
    • Modeling predicted that tobacco control policies targeted at lower educated will reduce the differences in life expectancy.

      Bemelmans, W J E; Lenthe, Frank J van; Hoogenveen, R; Kunst, A; Deeg, D J H; Brandt, P A van den; Goldbohm, R A; Verschuren, W M Monique (2006-09-01)
      BACKGROUND AND OBJECTIVE: To estimate the effects of reducing the prevalence of smoking in lower educated groups on educational differences in life expectancy. METHODS: A dynamic Markov-type multistate transition model estimated the effects on life expectancy of two scenarios. A "maximum scenario" where educational differences in prevalence of smoking disappear immediately, and a "policy target-scenario" where difference in prevalence of smoking is halved over a 20-year period. The two scenarios were compared to a reference scenario, where smoking prevalences do not change. Five Dutch cohort studies, involving over 67,000 participants aged 20 to 90 years, provided relative mortality risks by educational level, and smoking habits were assessed using national data of more than 120,000 persons. RESULTS: In the reference scenario, the difference in life expectancy at age 40 between highest and lowest educated groups was 5.1 years for men and 2.7 years for women. In the "maximum scenario" these differences were reduced to 3.6 years for men and 1.7 years for women (reduction approximately 30%), and in the "policy target-scenario" differences were 4.7 years for men and 2.4 years for women (reduction approximately 10%). CONCLUSION: Theoretically, educational differences in life expectancy would be reduced by 30% at maximum, if variations in smoking prevalence were eliminated completely. In practice, tobacco control policies that are targeted at the lower educated may reduce the differences in life expectancy by approximately 10%.
    • Modeling responses of Daphnia magna to pesticide pulse exposure under varying food conditions: intrinsic versus apparent sensitivity.

      Pieters, Barry J; Jager, Tjalling; Kraak, Michiel H S; Admiraal, Wim (2006-10-01)
      Recent studies showed that limiting food conditions resulted in either increased or decreased sensitivity of Daphnia magna to toxicants. It remained unclear whether these contrasting food-dependent alterations in toxicity resulted from differences in intrinsic sensitivity of the daphnids or from changes in toxicokinetics and resource allocation. It is hypothesized here that, if food level only affects accumulation kinetics and resource allocation, then the intrinsic sensitivity to this toxicant should be the same for all food regimes. This hypothesis was investigated using the DEBtox model, which is based on the theory of Dynamic Energy Budgets. We examined results of two recently conducted life-cycle studies on the combined effects of food level and a pulsed exposure to the pyrethroid insecticide fenvalerate (FV) on D. magna. The model described the effects of the time-varying exposure well, and indicated that when the animals did not die from exposure to FV, full reversibility of toxic effects was possible, allowing a complete recovery. Results revealed furthermore that the data from both studies could be described by the same NECs for survival and assimilation, killing rate and tolerance concentration (132 (49.2-228) x 10(-6) mug/L, 0 (0-1.18 x 10(-5)) mug/L, 74.4 (55.6-96.4) L (mug d)(-1) and 5.39 (2.72-18.5) x 10(-3) mug/L, respectively). It is therefore concluded that food-dependent FV toxicity can be explained by altered toxicokinetics and resource allocation, but not by changes in the intrinsic sensitivity of the daphnids. This study implies that the effect of pesticide application in the field depends on the trophic state of the receiving water body, but also that full recovery of survivors is possible after FV application.
    • Modelling human Puumala hantavirus infection in relation to bank vole abundance and masting intensity in the Netherlands.

      Swart, Arno; Bekker, Dick L; Maas, Miriam; de Vries, Ankje; Pijnacker, Roan; Reusken, Chantal B E M; van der Giessen, Joke W B (2017)
      This paper deals with modelling the relationship between human Puumala hantavirus (PUUV) infection, the abundance and prevalence of infection of the host (the bank vole), mast, and temperature. These data were used to build and parametrise generalised regression models, and parametrise them using datasets on these factors pertaining to the Netherlands. The performance of the models was assessed by considering their predictive power. Models including mast and monthly temperature performed well, and showed that mast intensity influences vole abundance and hence human exposure for the following year. Thus, the model can aid in forecasting of human illness cases, since (1) mast intensity influences the vole abundance and hence human exposure for the following year and (2) monitoring of mast is much more feasible than determining bank vole abundance.
    • Modelling long-term impacts of changes in climate, nitrogen deposition and ozone exposure on carbon sequestration of European forest ecosystems.

      de Vries, Wim; Posch, Maximilian; Simpson, David; Reinds, Gert Jan (2017-12-15)
      We modelled the effects of past and expected future changes in climate (temperature, precipitation), CO2 concentration, nitrogen deposition (N) and ozone (O3) exposure (phytotoxic ozone dose, POD) on carbon (C) sequestration by European forest ecosystems for the period 1900-2050. Tree C sequestration was assessed by using empirical response functions, while soil C sequestration was simulated with the process-based model VSD, combined with the RothC model. We evaluated two empirical growth responses to N deposition (linear and non-linear) and two O3 exposure relationships (linear function with total biomass or net annual increment). We further investigated an 'interactive model' with interactions between drivers and a 'multiplicative model', in which the combined effect is the product of individual drivers. A single deposition and climate scenario was used for the period 1900-2050. Contrary to expectations, growth observations at European level for the period 1950-2010 compared better with predictions by the multiplicative model than with the interactive model. This coincides with the fact that carbon responses in kgCha-1yr-1 per unit change in drivers, i.e. per °C, ppm CO2, kgNha-1yr-1 and mmolm-2yr-1 POD, are more in line with literature data when using the multiplicative model. Compared to 1900, the estimated European average total C sequestration in both forests and forest soils between 1950 and 2000 increased by 21% in the interactive model and by 41% in the multiplicative model, but observed changes were even higher. This growth increase is expected to decline between 2000 and 2050. The simulated changes between 1950 and 2000 were mainly due to the increase in both N deposition and CO2, while the predicted increases between 2000 and 2050 were mainly caused by the increase in CO2 and temperature, and to lesser extent a decrease in POD, counteracted by reduced N deposition.
    • Modelling pathogen load dynamics to elucidate mechanistic determinants of host-Plasmodium falciparum interactions.

      Georgiadou, Athina; Lee, Hyun Jae; Walther, Michael; van Beek, Anna E; Fitriani, Fadlila; Wouters, Diana; Kuijpers, Taco W; Nwakanma, Davis; D'Alessandro, Umberto; Riley, Eleanor M; et al. (2019-09-01)
    • A modelling study to evaluate the costs and effects of lowering the starting age of population breast cancer screening

      Koleva-Kolarova, Rositsa G.; Daszczuck, Alicja M.; de Jonge, Chris; Abu Hantash, Mohd Kahlil; Zhan, Zhuozhao Z.; Postema, Erik Jan; Feenstra, Talitha L.; Pijnappel, Ruud M.; Greuter, Marcel J.W.; de Bock, Geertruida H. (2018-03)
    • Modelling the dynamics of population viral load measures under HIV treatment as prevention.

      Rozhnova, Ganna; Anastasaki, Marilena; Kretzschmar, Mirjam (2018-01-01)
      In 2011 the Centers for Disease Control and Prevention (CDC) published guidelines for the use of population viral load (PVL), community viral load (CVL) and monitored viral load (MVL), defined as the average viral load (VL) of all HIV infected individuals in a population, of all diagnosed individuals, and of all individuals on antiretroviral treatment (ART), respectively. Since then, CVL has been used to assess the effectiveness of ART on HIV transmission and as a proxy for HIV incidence. The first objective of this study was to investigate how aggregate VL measures change with the HIV epidemic phase and the drivers behind these changes using a mathematical transmission model. Secondly, we aimed to give some insight into how well CVL correlates with HIV incidence during the course of the epidemic and roll out of ART. We developed a compartmental model for disease progression and HIV transmission with disease stages that differ in viral loads for epidemiological scenarios relevant to a concentrated epidemic in a population of men who have sex with men (MSM) in Western Europe (WE) and to a generalized epidemic in a heterosexual population in Sub-Saharan Africa (SSA). The model predicts that PVL and CVL change with the epidemic phase, while MVL stays constant. These dynamics are linked to the dynamics of infected subgroups (undiagnosed, diagnosed untreated and treated) in different disease stages (primary, chronic and AIDS). In particular, CVL decreases through all epidemic stages: before ART, since chronic population builds up faster than AIDS population and after ART, due to the build-up of treated population with low VL. The trends in CVL and incidence can be both opposing and coinciding depending on the epidemic phase. Before ART is scaled up to sufficiently high levels, incidence increases while CVL decreases. After this point, CVL is a useful indicator of changes in HIV incidence. The model predicts that during the ART scale-up HIV transmission is driven by undiagnosed and diagnosed untreated individuals, and that new infections decline due to the increase in the number of treated. Although CVL is not able to capture the contribution of undiagnosed population to HIV transmission, it declines due to the increase of people on ART too. In the scenarios described by our model, the present epidemic phase corresponds to declining trends in CVL and incidence.
    • Modelling the Impact of Different Tuberculosis Control Interventions on the Prevalence of Tuberculosis in an Overcrowded Prison.

      Naning, Herlianna; Al-Darraji, Haider Abdulrazzaq Abed; Mcdonald, Scott Alex; Ismail, Noor Azina; Kamarulzaman, Adeeba (2018-02-01)
      The aim of this study was to simulate the effects of tuberculosis (TB) treatment strategies interventions in an overcrowded and poorly ventilated prison with both high (5 months) and low (3 years) turnover of inmates against improved environmental conditions. We used a deterministic transmission model to simulate the effects of treatment of latent TB infection and active TB, or the combination of both treatment strategies. Without any intervention, the TB prevalence is estimated to increase to 8.8% for a prison with low turnover of inmates but modestly stabilize at 5.8% for high-turnover prisons in a 10-year period. Reducing overcrowding from 6 to 4 inmates per housing cell and increasing the ventilation rate from 2 to 12 air changes per hour combined with any treatment strategy would further reduce the TB prevalence to as low as 0.98% for a prison with low inmate turnover.
    • Modelling the long-term feed-to-fillet transfer of leuco crystal violet and leuco malachite green in Atlantic salmon (Salmo salar).

      Berntssen, Marc H G; Hannisdal, Rita; Buttle, Louise; Hoogenveen, Rudolf; Mengelers, Marcel; Bokkers, Bas G H; Zeilmaker, Marco J (2018-07-17)
      Leuco crystal violet (LCV) and leuco malachite green (LMG) are the main metabolites of two dyes that are forbidden for use in food production, but can be present at low background concentration in novel Atlantic salmon feed ingredients such as processed animal proteins (animal by-product [ABP]). In this study, the potential transfer of dietary LCV or LMG to the fillet of farmed Atlantic salmon was investigated. The uptake and elimination rate kinetics were determined in seawater-adapted Atlantic salmon (initial weight 587 ± 148 g) fed two levels of either LCV- or LMG-enriched diets (~500 and 4000 µg kg-1, respectively) for 40 days, followed by a 90-day depuration period with feeding on control diets (<0.15 μg kg-1 LCV and LMG). A three-compartmental model was developed, based on a fillet fat, fillet muscle and a central body compartment comprising all other tissues. Model calibrations showed a good fit with measured values during overall uptake and elimination period; however, the model poorly predicted the short-term (days) peak measured values at the end of the exposure period. The model was used to simulate the long-term (>16 months) LCV and LMG feed-to-fillet transfer in Atlantic salmon under realistic farming conditions such as the seasonal fluctuations in feed intake, growth and fillet fat deposition. The model predictions gave highest expected LCV and LMG fillet concentrations of approximately 0.12 and 0.45 μg kg-1, depending on the dietary levels of ABP and background level of LCV and LMG contamination. These levels are under the reference point for action of 2 µg kg-1 for the sum of MG and LMG that EFSA assessed as adequate to protect public health. However, for LCV, the predicted highest levels exceed the analytical decision limit (CCα) of 0.15 µg kg-1 for the method used in this paper.
    • Modelling the toxicity of a large set of metal and metal oxide nanoparticles using the OCHEM platform.

      Kovalishyn, Vasyl; Abramenko, Natalia; Kopernyk, Iryna; Charochkina, Larysa; Metelytsia, Larysa; Tetko, Igor V; Peijnenburg, Willie; Kustov, Leonid (2017-08-09)
      Inorganic nanomaterials have become one of the new areas of modern knowledge and technology and have already found an increasing number of applications. However, some nanoparticles show toxicity to living organisms, and can potentially have a negative influence on environmental ecosystems. While toxicity can be determined experimentally, such studies are time consuming and costly. Computational toxicology can provide an alternative approach and there is a need to develop methods to reliably assess Quantitative Structure-Property Relationships for nanomaterials (nano-QSPRs). Importantly, development of such models requires careful collection and curation of data. This article overviews freely available nano-QSPR models, which were developed using the Online Chemical Modeling Environment (OCHEM). Multiple data on toxicity of nanoparticles to different living organisms were collected from the literature and uploaded in the OCHEM database. The main characteristics of nanoparticles such as chemical composition of nanoparticles, average particle size, shape, surface charge and information about the biological test species were used as descriptors for developing QSPR models. QSPR methodologies used Random Forests (WEKA-RF), k-Nearest Neighbors and Associative Neural Networks. The predictive ability of the models was tested through cross-validation, giving cross-validated coefficients q2 = 0.58-0.80 for regression models and balanced accuracies of 65-88% for classification models. These results matched the predictions for the test sets used to develop the models. The proposed nano-QSPR models and uploaded data are freely available online at http://ochem.eu/article/103451 and can be used for estimation of toxicity of new and emerging nanoparticles at the early stages of nanomaterial development.
    • Modelling toxicity of metal mixtures: A generalisation of new advanced methods, considering potential application to terrestrial ecosystems

      Le, T. T. Yen; Peijnenburg, Willie J. G. M.; Faculty of Biology, Department of Aquatic Ecology, University of Duisburg-Essen, Essen, Germany; National Institute for Public Health and the Environment, Bilthoven, The Netherlands (2017-04-27)
    • Models for assessing engineered nanomaterial fate and behaviour in the aquatic environment.

      Williams, RJ; Harrison, S; Keller, V; Kuenen, J; Lofts, S; Praetorius, A; Svendsen, C; Vermeulen, LC; van Wijnen, J (2018-12-10)
    • Moderate alcohol consumption is associated with lower chronic disease burden expressed in disability-adjusted life years: a prospective cohort study.

      Beulens, Joline W J; Fransen, Heidi P; Struijk, Ellen A; Boer, Jolanda M A; de Wit, G Ardine; Onland-Moret, N Charlotte; Hoekstra, Jeljer; Bueno-de-Mesquita, H Bas; Peeters, Petra H M; May, Anne M (2017-04)
      The relation of alcohol consumption with disease burden remains debated partly due to opposite associations with cardiovascular disease (CVD) and cancer. The relation of alcohol consumption with disease burden expressed in disability-adjusted life years (DALYs) summarizes opposing associations of alcohol consumption on chronic diseases. This study aimed to investigate the association of alcohol consumption with chronic disease burden expressed in DALYs based on individual-participant data. The study was a prospective study among 33,066 men and women from the EPIC-NL cohort. At baseline, alcohol consumption was assessed with a validated food-frequency questionnaire. Participants were followed for occurrence of and mortality from chronic diseases and DALYs were calculated. After 12.4 years follow-up, 6647 disease incidences and 1482 deaths were documented, resulting in 68,225 healthy years of life lost (6225 DALYs). Moderate drinkers (women 5-14.9 g/day, men 5-29.9 g/day) had a lower chronic disease burden (mean DALYs -0.27; 95% CI -0.43; -0.11) than light drinkers (0-4.9 g/day), driven by a lower disease burden due to CVD (-0.18: -0.29; -0.06) but not cancer (-0.05: -0.16; 0.06). The associations were most pronounced among older participants (≥50 years; -0.32; -0.53; -0.10) and not observed among younger women (-0.08; -0.43; 0.35), albeit non-significant (pinteraction > 0.14). Substantial drinking (women 15-29.9 g/day, men 30-59.9 g/day) compared to light drinking was not associated with chronic disease burden. Our results show that moderate compared to light alcohol consumption was associated with living approximately 3 months longer in good health. These results were mainly observed among older participants and not seen among younger women.
    • Moderators of Exercise Effects on Cancer-related Fatigue: A Meta-analysis of Individual Patient Data.

      van Vulpen, Jonna K; Sweegers, Maike G; Peeters, Petra H M; Courneya, Kerry S; Newton, Robert U; Aaronson, Neil K; Jacobsen, Paul B; Galvão, Daniel A; Chinapaw, Mai J; Steindorf, Karen; et al. (2019-09-12)