HBM4EU chromates study - Reflection and lessons learnt from designing and undertaking a collaborative European biomonitoring study on occupational exposure to hexavalent chromium

Multicenter StudyThe EU human biomonitoring initiative, HBM4EU, aims to co-ordinate and advance human biomonitoring (HBM) across Europe. As part of HBM4EU, we presented a protocol for a multicentre study to characterize occupational exposure to hexavalent chromium (Cr(VI)) in nine European countries (HBM4EU chromates study). This study intended to collect data on current occupational exposure and to test new indicators for chromium (Cr) biomonitoring (Cr(VI) in exhaled breath condensate and Cr in red blood cells), in addition to traditional urinary total Cr analyses. Also, data from occupational hygiene samples and biomarkers of early biological effects, including genetic and epigenetic effects, was obtained, complementing the biomonitoring information. Data collection and analysis was completed, with the project findings being made separately available. As HBM4EU prepares to embark on further European wide biomonitoring studies, we considered it important to reflect on the experiences gained through our harmonised approach. Several practical aspects are highlighted for improvement in future studies, e.g., more thorough/earlier training on the implementation of standard operating procedures for field researchers, training on the use of the data entry template, as well as improved company communications. The HBM4EU chromates study team considered that the study had successfully demonstrated the feasibility of conducting a harmonised multicentre investigation able to achieve the research aims and objectives. This was largely attributable to the engaged multidisciplinary network, committed to deliver clearly understood goals. Such networks take time and investment to develop, but are priceless in terms of their ability to deliver and facilitate knowledge sharing and collaboration.Highlights: Feasibility of conducting harmonised Pan-European biomonitoring study on occupational exposure demonstrated; Developing a successful network and implementation of systematic methodology takes significant dedication from all involved; Methodological improvements were identified which will benefit future large-scale occupational biomonitoring campaigns; Developed multicentre network allows and promotes further opportunities for future research, knowledge sharing and collaboration; Data produced supports science to policy interface in the scope of REACH and occupational safety and health regulations.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 733032 and received co-funding from the author’s organizations and/or Ministries.info:eu-repo/semantics/publishedVersio

reflection and lessons learnt from designing and undertaking a collaborative European biomonitoring study on occupational exposure to hexavalent chromium

The EU human biomonitoring initiative, HBM4EU, aims to co-ordinate and advance human biomonitoring (HBM) across Europe. As part of HBM4EU, we presented a protocol for a multicentre study to characterize occupational exposure to hexavalent chromium (Cr(VI)) in nine European countries (HBM4EU chromates study). This study intended to collect data on current occupational exposure and to test new indicators for chromium (Cr) biomonitoring (Cr(VI) in exhaled breath condensate and Cr in red blood cells), in addition to traditional urinary total Cr analyses. Also, data from occupational hygiene samples and biomarkers of early biological effects, including genetic and epigenetic effects, was obtained, complementing the biomonitoring information. Data collection and analysis was completed, with the project findings being made separately available. As HBM4EU prepares to embark on further European wide biomonitoring studies, we considered it important to reflect on the experiences gained through our harmonised approach. Several practical aspects are highlighted for improvement in future studies, e.g., more thorough/earlier training on the implementation of standard operating procedures for field researchers, training on the use of the data entry template, as well as improved company communications. The HBM4EU chromates study team considered that the study had successfully demonstrated the feasibility of conducting a harmonised multicentre investigation able to achieve the research aims and objectives. This was largely attributable to the engaged multidisciplinary network, committed to deliver clearly understood goals. Such networks take time and investment to develop, but are priceless in terms of their ability to deliver and facilitate knowledge sharing and collaboration.publishersversionpublishe

urinary metabolomics study of workers exposed to hexavalent chromium

Exposure to hexavalent chromium Cr(VI) may occur in several occupational activities, placing workers in many industries at risk for potential related health outcomes. Untargeted metabolomics was applied to investigate changes in metabolic pathways in response to Cr(VI) exposure. We obtained our data from a study population of 220 male workers with exposure to Cr(VI) and 102 male controls from Belgium, Finland, Poland, Portugal and the Netherlands within the HBM4EU Chromates Study. Urinary metabolite profiles were determined using liquid chromatography mass spectrometry, and differences between post-shift exposed workers and controls were analyzed using principal component analysis. Based on the first two principal components, we observed clustering by industrial chromate application, such as welding, chrome plating, and surface treatment, distinct from controls and not explained by smoking status or alcohol use. The changes in the abundancy of excreted metabolites observed in workers reflect fatty acid and monoamine neurotransmitter metabolism, oxidative modifications of amino acid residues, the excessive formation of abnormal amino acid metabolites and changes in steroid and thyrotropin-releasing hormones. The observed responses could also have resulted from work-related factors other than Cr(VI). Further targeted metabolomics studies are needed to better understand the observed modifications and further explore the suitability of urinary metabolites as early indicators of adverse effects associated with exposure to Cr(VI).publishersversionpublishe

usefulness of measurement of blood chromium levels in the assessment of occupational Cr(VI) exposure

Funding Information: This work has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 733032 and received co-funding from the author's organizations and/or Ministries. Luxembourg entered the study at a later stage and thus financed the study at its own means. Publisher Copyright: © 2022 The AuthorsOccupational exposures to hexavalent Chromium (Cr(VI)) can occur in welding, hot working stainless steel processing, chrome plating, spray painting and coating activities. Recently, within the human biomonitoring for Europe initiative (HBM4EU), a study was performed to assess the suitability of different biomarkers to assess the exposure to Cr(VI) in various job tasks. Blood-based biomarkers may prove useful when more specific information on systemic and intracellular bioavailability is necessary. To this aim, concentrations of Cr in red blood cells (RBC-Cr) and in plasma (P–Cr) were analyzed in 345 Cr(VI) exposed workers and 175 controls to understand how these biomarkers may be affected by variable levels of exposure and job procedures. Compared to controls, significantly higher RBC-Cr levels were observed in bath plating and paint application workers, but not in welders, while all the 3 groups had significantly greater P–Cr concentrations. RBC-Cr and P–Cr in chrome platers showed a high correlation with Cr(VI) in inhalable dust, outside respiratory protective equipment (RPE), while such correlation could not be determined in welders. In platers, the use of RPE had a significant impact on the relationship between blood biomarkers and Cr(VI) in inhalable and respirable dust. Low correlations between P–Cr and RBC-Cr may reflect a difference in kinetics. This study showed that Cr-blood-based biomarkers can provide information on how workplace exposure translates into systemic availability of Cr(III) (extracellular, P–Cr) and Cr(VI) (intracellular, RBC-Cr). Further studies are needed to fully appreciate their use in an occupational health and safety context.publishersversionpublishe

HBM4EU chromates study: determinants of exposure to hexavalent chromium in plating, welding and other occupational settings

Work-related exposures in industrial processing of chromate (chrome plating, surface treatment, and welding) raise concerns regarding the health risk of hexavalent chromium (Cr(VI)). In this study, performed under the HBM4EU project, we focused on better understanding the determinants of exposure and recognising how risk management measures (RMMs) contribute to a reduction in exposure. HBM and occupational hygiene data were collected from 399 workers and 203 controls recruited in nine European countries. Urinary total chromium (U-Cr), personal inhalable and respirable dust of Cr and Cr(VI), and Cr from hand wipes were collected. Data on the RMMs were collected by questionnaires. We studied the association between different exposure parameters and the use of RMMs. The relationship between exposure by inhalation and U-Cr in different worker groups was analysed using regression analysis and found a strong association. Automatisation of Cr electroplating dipping explained lower exposure levels in platers. The use of personal protective equipment resulted in lower U-Cr levels in welding, bath plating, and painting. An effect of wearing gloves was observed in machining. An effect of local exhaust ventilation and training was observed in welding. Regression analyses showed that in platers, exposure to an air level of 5 µg/m3 corresponds to a U-Cr level of 7 µg/g of creatinine. In welders, the same inhalation exposure resulted in lower U-Cr levels reflecting toxicokinetic differences of different chromium species.info:eu-repo/semantics/publishedVersio

HBM4EU chromates study - Usefulness of measurement of blood chromium levels in the assessment of occupational Cr(VI) exposure

Occupational exposures to hexavalent Chromium (Cr(VI)) can occur in welding, hot working stainless steel processing, chrome plating, spray painting and coating activities. Recently, within the human biomonitoring for Europe initiative (HBM4EU), a study was performed to assess the suitability of different biomarkers to assess the exposure to Cr(VI) in various job tasks. Blood-based biomarkers may prove useful when more specific information on systemic and intracellular bioavailability is necessary. To this aim, concentrations of Cr in red blood cells (RBC-Cr) and in plasma (P-Cr) were analyzed in 345 Cr(VI) exposed workers and 175 controls to understand how these biomarkers may be affected by variable levels of exposure and job procedures. Compared to controls, significantly higher RBC-Cr levels were observed in bath plating and paint application workers, but not in welders, while all the 3 groups had significantly greater P-Cr concentrations. RBC-Cr and P-Cr in chrome platers showed a high correlation with Cr(VI) in inhalable dust, outside respiratory protective equipment (RPE), while such correlation could not be determined in welders. In platers, the use of RPE had a significant impact on the relationship between blood biomarkers and Cr(VI) in inhalable and respirable dust. Low correlations between P-Cr and RBC-Cr may reflect a difference in kinetics. This study showed that Cr-blood-based biomarkers can provide information on how workplace exposure translates into systemic availability of Cr(III) (extracellular, P-Cr) and Cr(VI) (intracellular, RBC-Cr). Further studies are needed to fully appreciate their use in an occupational health and safety context.Highlights: - Suitability of blood biomarkers was evaluated to assess occupational Cr(VI)exposure; - Bath platers and painters had higher Red Blood Cells-Cr levels compared to controls; - Bath platers, painters and welders had higher plasma-Cr levels compared to controls; Red Blood Cells- and Plasma-Cr were highly correlated with inhalable Cr(VI) in platers; Blood-Cr biomarkers can provide information on systemic and intracellular availability.This work has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 733032 and received co-funding from the author’s organizations and/or Ministries. Luxembourg entered the study at a later stage and thus financed the study at its own means.info:eu-repo/semantics/publishedVersio

The HBM4EU chromates study – Outcomes and impacts on EU policies and occupational health practices

Within the EU human biomonitoring initiative (HBM4EU), a targeted, multi-national study on occupational exposure to hexavalent chromium (Cr(VI)) was performed. Cr(VI) is currently regulated in EU under REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) and under occupational safety and health (OSH) legislation. It has recently been subject to regulatory actions to improve its risk management in European workplaces. Analysis of the data obtained within the HBM4EU chromates study provides support both for the implementation of these regulatory actions and for national enforcement programs and may also contribute to the updating of occupational limit values (OELs) and biological limit values for Cr(VI). It also provides useful insights on the contribution of different risk management measures (RMMs) to further reduce the exposure to Cr(VI) and may support the evaluation of applications for authorisation under REACH. Findings on chrome platers’ additional per- and polyfluoroalkyl substances (PFAS) exposure highlight the need to also pay attention to this substance group in the metals sector. A survey performed to evaluate the policy relevance of the HBM4EU chromates study findings supports the usefulness of the study results. According to the responses received from the survey, the HBM4EU chromates study was able to demonstrate the added value of the human biomonitoring (HBM) approach in assessment and management of occupational exposure to Cr(VI). For future occupational studies, we emphasise the need for engagement of policy makers and regulators throughout the whole research process to ensure awareness, relevance and uptake of the results in future policies.Highlights: Potential policy impact of the HBM4EU chromates study is presented and discussed; Surveyed policy makers confirmed policy relevance of biomonitoring results; Study considered to support national enforcement and further lowering of OELs; Added value of HBM in the management of occupational exposure to Cr(VI) was demonstrated; Close co-operation with regulators to support policy uptake is emphasised.Funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 733032 and received co-funding from the author's organizations and/or Ministries.info:eu-repo/semantics/publishedVersio

The HBM4EU chromates study – Outcomes and impacts on EU policies and occupational health practices

Funding Information: The recently completed EU human biomonitoring initiative (HBM4EU, www.hbm4eu.eu/about-hbm4eu/), was a European Joint Programme that aimed to harmonise the collection and use of biomonitoring data to better understand human exposure to chemicals in the environment, in occupational settings and through the use of consumer products to improve chemical risk assessment and management efforts, and to support policy making (Ganzleben et al., 2017). Within the context of the HBM4EU project several priority substances were selected for investigation based on the most important needs of policy makers and risk assessors, as well as common needs of participating countries and a broad range of other stakeholders including trade unions (Ougier et al., 2021). Many of the priority substances, along with having an important economic role, also pose health risks for workers due to their occupational use. One of the priority substances was hexavalent chromium (Cr(VI)), which was the main focus of the first of a series of three different HBM4EU occupational studies (Santonen et al. 2019a, 2022), the other two being focussed on electronic waste (E-waste) and diisocyanates exposures (Jones et al., 2022; Scheepers et al., 2021). In addition to Cr(VI), it was recognised that in chrome plating activities there may also be exposure to another group of HBM4EU priority chemicals, per- and polyfluoroalkyl substances (PFASs). PFASs, including PFOS (perfluorooctane sulfonate), have been used as mist suppressants in chrome plating baths to prevent the evaporation of Cr(VI) vapours (Blepp et al., 2017; Gluge et al., 2020). Although PFOS has now been largely replaced in the EU, many of its substitutes in chrome plating activities are also PFASs which may cause similar health and environmental concerns.Occupational exposure to Cr(VI) has been associated with an increased risk of lung and sinonasal cancers and is suspected to lead to gastrointestinal tract cancers (den Braver-Sewradj et al., 2021; ECHA 2013; IARC 2012). In addition, it is a common cause of occupational asthma, allergic dermatitis and there is a concern for adverse effects on reproductive health (Sun and Costa 2022). Exposure to Cr(VI) may occur in several occupational activities, e.g., in welding, Cr(VI) electroplating and other surface treatment processes such as paint application and removal of old paint containing Cr(VI) (SCOEL 2017). In order to limit the workers’ exposure to Cr(VI) in the EU, Cr(VI) is currently regulated under both the European regulation (EC 1907/2006) on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) and the EU Directive 2004/37/EC on the protection of workers from the risks related to exposure to carcinogens, mutagens or reprotoxic substances at work (CMRD) (EU 2004). The current binding Occupational Exposure Limit (OEL) set under the EU Directive 2004/37/EC is 10 μg/m3 (8-h time-weighted average (8-h TWA)) until January 17, 2025. After that period, the OEL (8-h TWA) will be reduced to 5 μg/m3. For welding, plasma-cutting processes and similar work processes that generate fumes, there is a derogation with an OEL of 25 μg/m³ (8-h TWA) until January 2025; after that date the OEL (8-h TWA) of 5 μg/m3 will be applicable. France, the Netherlands and Denmark already have stricter limits, with an OEL of 1 μg/m3 (8-h TWA) for Cr(VI) in all uses (Beskæftigelsesministeriet 2020; Ministère du travail, 2012; MinSZW 2016). In the US, the American Conference of Governmental Industrial Hygienists (ACGIH) has published, for inhalable Cr(VI) compounds, a threshold limit value (TLV) of 0.2 μg/m3 (8-h TWA) and a TLV Short-Term Exposure Limit (STEL) of 0.5 μg/m3 (ACGIH 2021). No EU-wide biological limit values (BLVs) for Cr(VI) are available, however some Member States have set BLVs for occupational exposure to Cr(VI), measured as urinary chromium (U–Cr). For example, France and Finland have derived BLVs of 2.5 μg/L and 10 μg/L corresponding to their respective OELs of 1 μg/m3 and 5 μg/m3 for Cr(VI) (ANSES 2017; STM 2020). The German Research Foundation (DFG 2020) has established biological exposure equivalents for carcinogenic substances (EKA values), ranging from 12 to 40 μg/L for U–Cr. These correspond to exposures ranging between 30 and 100 μg/m3 soluble alkaline chromate and/or Cr(VI) containing welding fumes over an 8-h work shift (Bolt and Lewalter 2012). Since these current national BLVs are mainly based on studies from plating workers, they include uncertainties especially concerning their applicability to workplaces other than the electroplating industry. One of the main aims of the HBM4EU chromates study was to provide EU relevant data on the current occupational Cr(VI) exposure to support the regulatory risk assessment and decision-making process. In addition, exposure to PFASs was evaluated in a subset of workers performing chrome plating activities.This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 733032 and received co-funding from the author's organizations and/or Ministries. The project team would like to thank all the companies and workers who participated in the HBM4EU chromates study and all the experts who have contributed to the conduct of the study. Participants of the HBM4EU chromates study workshop and policy questionnaires are also acknowledged. Mr. Jouko Remes and Dr. Kia Gluschkoff (Finnish Institute of Occupational Health) are acknowledged for their assistance with the statistical analyses and figures. Funding Information: This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 733032 and received co-funding from the author's organizations and/or Ministries. Publisher Copyright: © 2022 The AuthorsWithin the EU human biomonitoring initiative (HBM4EU), a targeted, multi-national study on occupational exposure to hexavalent chromium (Cr(VI)) was performed. Cr(VI) is currently regulated in EU under REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) and under occupational safety and health (OSH) legislation. It has recently been subject to regulatory actions to improve its risk management in European workplaces. Analysis of the data obtained within the HBM4EU chromates study provides support both for the implementation of these regulatory actions and for national enforcement programs and may also contribute to the updating of occupational limit values (OELs) and biological limit values for Cr(VI). It also provides useful insights on the contribution of different risk management measures (RMMs) to further reduce the exposure to Cr(VI) and may support the evaluation of applications for authorisation under REACH. Findings on chrome platers’ additional per- and polyfluoroalkyl substances (PFAS) exposure highlight the need to also pay attention to this substance group in the metals sector. A survey performed to evaluate the policy relevance of the HBM4EU chromates study findings supports the usefulness of the study results. According to the responses received from the survey, the HBM4EU chromates study was able to demonstrate the added value of the human biomonitoring (HBM) approach in assessment and management of occupational exposure to Cr(VI). For future occupational studies, we emphasise the need for engagement of policy makers and regulators throughout the whole research process to ensure awareness, relevance and uptake of the results in future policies.publishersversionepub_ahead_of_prin

Cadmium exposure in adults across Europe: Results from the HBM4EU Aligned Studies survey 2014-2020

ReviewThe objectives of the study were to estimate the current exposure to cadmium (Cd) in Europe, potential differences between the countries and geographic regions, determinants of exposure and to derive European exposure levels. The basis for this work was provided by the European Human Biomonitoring Initiative (HBM4EU) which established a framework for alignment of national or regional HBM studies. For the purpose of Cd exposure assessment, studies from 9 European countries (Iceland, Denmark, Poland, Czech Republic, Croatia, Portugal, Germany, France, Luxembourg) were included and urine of 20–39 years old adults sampled in the years 2014–2021 (n = 2510). The measurements in urine were quality assured by the HBM4EU quality assurance/quality control scheme, study participants' questionnaire data were post-harmonized. Spatially resolved external data, namely Cd concentrations in soil, agricultural areas, phosphate fertilizer application, traffic density and point source Cd release were collected for the respective statistical territorial unit (NUTS). There were no distinct geographic patterns observed in Cd levels in urine, although the data revealed some differences between the specific study sites. The levels of exposure were otherwise similar between two time periods within the last decade (DEMOCOPHES - 2011–2012 vs. HBM4EU Aligned Studies, 2014–2020). The age-dependent alert values for Cd in urine were exceeded by 16% of the study participants. Exceedances in the different studies and locations ranged from 1.4% up to 42%. The studies with largest extent of exceedance were from France and Poland. Association analysis with individual food consumption data available from participants’ questionnaires showed an important contribution of vegetarian diet to the overall exposure, with 35% higher levels in vegetarians as opposed to non-vegetarians. For comparison, increase in Cd levels due to smoking was 25%. Using NUTS2-level external data, positive associations between HBM data and percentage of cropland and consumption of Cd-containing mineral phosphate fertilizer were revealed, which indicates a significant contribution of mineral phosphate fertilizers to human Cd exposure through diet. In addition to diet, traffic and point source release were identified as significant sources of exposure in the study population. The findings of the study support the recommendation by EFSA to reduce Cd exposure as also the estimated mean dietary exposure of adults in the EU is close or slightly exceeding the tolerable weekly intake. It also indicates that regulations are not protecting the population sufficiently.The HBM4EU project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 733032. Co-funding for the HBM4EU Aligned Studies has been provided by the national programs: Sant´e Publique France and the French ministries of Health and the Environment (ESTEBAN, France); MEYS (No. LM2018121), and Cetocoen Plus project (CZ.02.1.01/0.0/ 0.0/15_003/0000469) (CELSPAC:YA, Czech Republic); the Ministry of Science and Higher Education of Poland (contract no.3764/H2020/ 2017/2) (POALES, Poland); Public Health Fund (Diet_HBM, Iceland); Croatian Institute of Public Health (HBM survey in Croatia); National Institute of Health Dr Ricardo Jorge (INSEF_ExpoQuim, Portugal); German Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV) (ESB, Germany); Luxembourg Institute of Health (LIH), the Laboratoire national de sant´e (human biomonitoring part), the Ministry of Higher Education and Research of Luxembourg and the Ministry of Health of Luxembourg (Oriscav-Lux2, Luxembourg); Candy Foundation (Nos. 2017–224 and 2020–344), Absalon Foundation (No. F-23653-01), The Danish Environmental Protection Agency (Miljøstyrelsen: MST-621-00012 Center on Endocrine Disrupters), The Research council of Capital Region of Denmark (No. E− 22717-11), Research council of Rigshospitalet (Nos. E− 22717-12, E− 22717-07, E− 22717-08), Aase og Ejnar Danielsens Fond (No. 10–001874), International Research and Research Training Centre for Male Reproduction and Child Health (EDMaRC, No. 1500321/1604357) (CPHMINIPUB (parents) and DYMS, Denmark). J.Kl. and L.A. thank the CETOCOEN EXCELLENCE project No. CZ.02.1.01/0.0/0.0/17_043/ 0009632 financed by MEYS for supportive background, and supported from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 857560.info:eu-repo/semantics/publishedVersio

HBM4EU chromates study - Overall results and recommendations for the biomonitoring of occupational exposure to hexavalent chromium

Exposure to hexavalent chromium [Cr(VI)] may occur in several occupational activities, e.g., welding, Cr(VI) electroplating and other surface treatment processes. The aim of this study was to provide EU relevant data on occupational Cr(VI) exposure to support the regulatory risk assessment and decision-making. In addition, the capability and validity of different biomarkers for the assessment of Cr(VI) exposure were evaluated. The study involved nine European countries and involved 399 workers in different industry sectors with exposures to Cr(VI) such as welding, bath plating, applying or removing paint and other tasks. We also studied 203 controls to establish a background in workers with no direct exposure to Cr(VI). We applied a cross-sectional study design and used chromium in urine as the primary biomonitoring method for Cr(VI) exposure. Additionally, we studied the use of red blood cells (RBC) and exhaled breath condensate (EBC) for biomonitoring of exposure to Cr(VI). Personal measurements were used to study exposure to inhalable and respirable Cr(VI) by personal air sampling. Dermal exposure was studied by taking hand wipe samples. The highest internal exposures were observed in the use of Cr(VI) in electrolytic bath plating. In stainless steel welding the internal Cr exposure was clearly lower when compared to plating activities. We observed a high correlation between chromium urinary levels and air Cr(VI) or dermal total Cr exposure. Urinary chromium showed its value as a first approach for the assessment of total, internal exposure. Correlations between urinary chromium and Cr(VI) in EBC and Cr in RBC were low, probably due to differences in kinetics and indicating that these biomonitoring approaches may not be interchangeable but rather complementary. This study showed that occupational biomonitoring studies can be conducted successfully by multi-national collaboration and provide relevant information to support policy actions aiming to reduce occupational exposure to chemicals.This work has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 733032 and received co-funding from the author's organizations and/or Ministries. Luxembourg entered the study at a later stage and thus financed the study at its own means.S