LifeLines for Researchers

Transcription

1 LifeLines for Researchers A unique resource of data, samples and expertise

2 Hanneke Jansen MD/PhD, investigated the level of HbA1c in the blood of 2,921 non-diabetic adults. Experts suggested the use of HbA1c levels to diagnose new-onset diabetes. LifeLines data on Body Mass Index, waist circumference, fasting plasma glucose, erythrocyte indices, current smoking and alcohol use, and genome-wide genetic data revealed that high HbA1c levels are determined by other factors besides preceding glucose levels. The use of HbA1c levels may therefore not be suitable to diagnose diabetes. My experience with LifeLines data was very good: the data was clear and ready-to-use. When I had questions about the data, I got a quick answer. Bart Klijs Health scientist, studies depression, highly prevalent in modern western societies. We believe that people evaluate themselves in relation to others. We disentangled how socio-economic position compared to the average position of people living in the same neighbourhood- is related to depression. Our research is embedded in a larger programme on the societal aspects of healthy ageing. Our LifeLines data are enriched with information on neighbourhood level income from Statistics Netherlands. Given its large sample size, the geographical spread of participants and the diagnostic instrument used to establish depression, the LifeLines dataset is uniquely suited for the project.

3 Content Contact UMCG LifeLines P.O. Box Groningen Website: lifelines.net LifeLines 2013 Colofon Text: Marije van Beilen Psychologie & Wetenschapscommunicatie (Marije van Beilen & Corinne van Beilen) Design and infographics: Kuenst.nl (Nynke Kuipers & Meinte Strikwerda) Photo s: Henk Veenstra, Jeroen van Kooten and others Prephase 3 LifeLines 4 LifeLines for Researchers 6 Cohort Study and Biobank 8 Interview Pim van der Harst 10 Access to LifeLines 12 LifeLines Extensive Networks 14 Interview Judith Rosmalen 16 LifeLines Scientific Organization 18 LifeLines Data Collection 20 1

4 Steef Sinkeler MD, improves the estimations of renal function for scientific purposes. The number of patients at risk for renal disease is growing rapidly due to a higher prevalence of diabetes and cardiovascular problems. We need reliable measures to identify patients-atrisk in an early stage. The accuracy of the widely used measurement to assess renal functioning is questionable. A method based on urine creatinine excretion- is more accurate, provided urine is collected adequately. With the LifeLines cohort we developed a sophisticated formula to assess creatinine excretion that allows a more accurate estimation of renal function world-wide. 2

5 Prephase This first scientific report marks the start of the next phase of LifeLines. After more than five years of data collection, these data are now ready to be explored by researchers. Not just data, but a whole infrastructure is available for investigators in The Netherlands and abroad, from both public and private institutions. Apart from the large scale high quality data in many domains, LifeLines provides state of the art high performance computer power, a team of methodological experts, an (inter)national network of biobank researchers, and later this year a fully automated biorepository to retrieve a selection from the millions of stored biosamples overnight. The examinations of the LifeLines cohort continue and there are ample opportunities for researchers to add their own assessment in the entire 165,000 participants or in a subgroup they select. From assays in fresh or stored samples to additional tests or questionnaires. Again, experts are available to help from methodological issues to valorization and IP solutions. The scientific opportunities of LifeLines are described in this report, more details are available on We are looking forward to welcome researchers to the LifeLines community. Please submit a proposal to use the data or add to the data collection. We are proud to the opportunities of LifeLines to contribute to improve knowledge on Healthy Ageing, and are eager to share these with researchers world-wide. On behalf of the LifeLines scientific crew, Ronald Stolk Professor of Clinical Epidemiology Chief Scientific Officer LifeLines 3

6 LifeLines is one of the world s largest population-based studies and offers a unique data and biomaterial resource to researchers world-wide. Its cohort study and biobank link information on environmental exposures, (epi)genetics, nutritional, psychological and social factors, as well as data on health care use to cover societal impact. It forms a pivotal base for important breakthroughs in the screening, prevention, diagnosis, and treatment of (chronic) diseases as well as in the understanding of the etiology of disease. The developed infrastructure enables to perform both large-scale and detailed epidemiological studies to gene-environmental factors in a broad range of multifactorial diseases. Only this multidimensional and multidisciplinary approach will deliver the depth of insight required to understand the origins and course of (chronic) diseases. LifeLines LifeLines broad scope, large study population and long follow-up make it one of the world s most valuable multidimensional cohort studies and biobanks Large sample: 165,000 individuals (expected in December 2013), covering three generations Scope: (epi)genetic, biomedical, nutritional, psychological, social and environmental factors in relation to healthy ageing, disease development and general well-being Follow-up: for the duration of participant s life; collection of detailed follow-up data and biomaterial with extensive standardized measurements Started:

7 Interactive Data Exchange at Multiple Measurement Levels dimensions environment expanding data bank social psychologic nutrition/ lifestyle biomedic (epi)genetic add-on studies collecting data data linkage 5

8 LifeLines for Researchers As LifeLines cohort study and biobank has no pre-determined research objective, it caters to a wide range of research disciplines The research infrastructure, as well as data and biomaterials collected by LifeLines can be utilized by a great number of researchers from a variety of clinical, biomedical, genetic, psychological, environmental and sociological disciplines. LifeLines was established as an open research infrastructure with ample opportunities to include additional measurements to the protocol. Access to LifeLines benefits clinical as well as fundamental research purposes, and is suited to the individual researcher as well as large international research programmes. Researchers from various backgrounds are currently working with the LifeLines data. 6

9 LifeLines offers researchers the unique opportunity to add questionnaire and measurements to the LifeLines protocol to answer their research question 13% 4% 6% 10% 67% Type of requests Sample request Linkage external data Additional data collection Infrastructure project Data request Facilitation and Research Infrastructure Researchers gain access to a research infrastructure that opens up a broad range of opportunities, comprising: An elaborated, longitudinal cohort and biobank with biomaterial A collaborative network of other researchers working with LifeLines data, and other biobanks A center of expertise on biobanking, ensuring the best possible service and quality of data and biomaterials, as well as support in statistical analyses Researchers Own Additions to Data Collection In addition to accessing the collected data and biomaterials, researchers can add data to the LifeLines research infrastructure for their own specific research question. LifeLines can send an additional questionnaire or perform additional measurement on a specific topic of interest of the researcher to (a subgroup of) the LifeLines population. Examples of implemented additional research: Additional questionnaire for subgroup of the population: questionnaire on burden of informal care givers Additional measurements/ samples: detailed genomics data Linking of external data sources: geocoding, neighbourhood characteristics, air pollution Linking of patient-based biobank with LifeLines biobank Also, external data sources can be linked to the LifeLines data. In short, LifeLines infrastructure, cohort, knowledge and know-how is at the disposal of researchers to answer their specific research questions. This saves researchers valuable time, while being ensured of high quality, ready-to-use data. In this role, LifeLines facilitates the creation of research communities by matching researchers who are working with similar data and have joint research interests. Direct Available Data All LifeLines data is monitored on inconsistencies and can be accessed through a remote access procedure, which runs on a high performance computer cluster. Researchers currently have access to ready-to-use complete baseline data of 95,000 participants. Recurrent data releases (more participants and followup data) will become available every six months. When researchers request collection of additional data, the data release will take more time. 7

10 LifeLines has a unique three generation design Cohort Study and Biobank Three Generations: LifeLines Cohort Dimensions Index persons: invited to participate through their general practitioner Probands invite their family members (parents, partner, parents-in-law and children) to take part Father Mother Index persons (25 50 years) A-SELECT: 45,000 CHILDREN: 35,000 This results in a three-generation study Based on the age of the participant, they are included in the children s protocol (0 18 years), the adult protocol (18 65 years) or the elderly protocol (> 65 years) PARENTS ALIVE: 55,000 For children five specific sub-protocols are developed, corresponding with the different developmental stages Child Child Child Men 56,802 Women 79,812 TOTAL NUMBER OF PARTICIPANTS: 165,000 Total 136,614 Partner s Father Partner s Mother Partner PARTNER: 30,000 Number of participants as per 22 May 2013 Based on estimated numbers 8

11 5 years 5 years 1,5 years 1,5 years 1,5 years 1,5 years 1,5 years 1,5 years 1,5 years Baseline visit & follow-up visits Follow-up data collection Follow-up by record linkage The homogenous composition of the population in the North of The Netherlands is highly suitable for observational follow-up studies, as people in the Dutch Northern provinces tend to keep living in the same area for many generations. LifeLines covers three generations and has a high response rate. This design enables the prospective investigation of risk factors, which is crucial in the study of (health) behavioural and environmental and other time-varying exposures, as well as interactions between genetic and environmental risk factors. Key benefits of this three-generation design: Vast statistical advantages: multiple-level information, separation of non-genetic and genetic familial transmission, direct haplotype assessment, and increased power and precision Unique possibilities to study social characteristics: socioeconomic mobility, partner preferences, and betweengeneration similarities Data Collection and Sample Storage All participants receive a number of questionnaires and a medical examination. Fasting blood samples and 24-hour urine are collected for long term storage and to perform laboratory measurements. The participants are followed for at least thirty years and are invited every five years for a medical examination at a local LifeLines research facility. In the years in-between the participants receive follow-up questionnaires. Follow-up on morbidity and mortality will also be based on general practitioners, hospital and pharmacy records. Conditioned transport of blood and urine samples towards the highly automated LifeLines laboratory guarantees complete traceability. Samples are analyzed and stored at -80 C on the same day of collection. Uniquely 2D barcoded labware are used for storage. LifeStore The storage facility of LifeLines, Life- Store is currently under construction in Groningen, The Netherlands, and will be fully operational beginning This is a completely automated sample storage with a capacity of 8+ million aliquots at -80 C which will do fully automated overnight sample retrieval. Storage of blood and urine samples at high quality standards at different time points (every 5 year) facilitates the researchers to go back in time to investigate traces of diseases and the effects different of treatments in the carefully processed and registered biomaterials. Timeline Baseline visit: Participants visit LifeLines Research Site Measurements Sample collection (blood and 24-hour urine) Questionnaires Second visit fasting At home: 24h urine collection and questionnaires Follow-up data collection (every 1,5 years) Questionnaires Follow-up New questions (requested by researchers) Food frequency questionnaire Follow-up by record linkage (continuously) Link with external data Hospitals records Follow-up visit (every 5 years) Measurements ECG, anthropometry, lung function, blood pressure, cognition Sample collection (fasting blood, 24h urine, scalp hair and faeces) Questionnaires 9

12 PHOTO: JEROEN VAN KOOTEN Interview Pim van der Harst LifeLines makes you an attractive partner for top research groups all over the world Our genes are at the heart of all bodily functions and present in each of our cells. Variations in genes determine our health throughout our lives. The heart function itself is influenced by a great number of genes and variations of those genes. Genetic and environmental factors constantly interact: they jointly affect the heart and other bodily functions. The integration of genetic and environmental factors form one of the main themes in the LifeLines Healthy Ageing research. You investigated the relationship between genetic variation and heart function. How did you make use of the LifeLines data? In a proportion of LifeLines participants we have genotype data available covering the entire human genome. This allows us to perform GWAS studies. GWAS short for Genome Wide Association Studyconcerns the investigation of common genetic variants in different individuals to link specific genetic information to specific human traits. Genetics research obviously 10

13 require large numbers: with more than 2,5 million variations on the genome we need to deal with the multiple comparisons problem. We investigated the variations in the human genome in a very large sample of 120,000 participants. For this, we combined the LifeLines data with data from other large biobanks. This way, we found a total of 61 regions in the DNA associated with heart function. Heart function is related to 61 different regions in the DNA? That is much more complex than I would have imagined. And we only looked for the regions related to particular aspects of the electrocardiogram (ECG), there are many more to find if you broaden our view. We are interested to isolate genes that are also related to the development of heart failure and therefore narrowed our view to particular aspects of the ECG. But it is indeed more complex as heart function is not an isolated bodily function determining heart failure symptoms or healthy ageing in general: it is related to, for example, kidney and pulmonary function, the number of red blood cells or social and psychological factors. Life- Lines data offered us the opportunity to investigate the associations between all these different factors. As a cardiologist, it is important to learn about the combination of risk factors, that all contribute in some way to the development of heart disease. After all, many patients come in with multiple illnesses, comorbidity is a significant problem. We need to be able to understand the patients condition, as they enter the clinic. They are not an isolated set of genes, after all, every patient has his own unique environmental history and health behavior. If we know which genes are involved and which environmental factors contribute, we will be able to increase our understanding which might help us diagnose heart disease in an earlier phase and improve prevention of illness. What did you find, specifically? Well, first of all, we discovered new sets of candidate genes that influence heart function. Some of these genes were never related to cardiac disease before. I find it very exciting to identify new genes that potentially regulate the size of heart cells and the way these cells behave and put someone at risk to develop heart disease. Also these first findings might be helpful to identify new potential targets of therapy to which we can design new medicine. That paper was published in Nature, quite a success! I noticed that -at 34 years oldyou finished your training as a cardiologist last year. Despite the large amount of time consumed by a medical education, your h-index has already reached 24. In addition to the scientific results we discussed; what did using LifeLines data bring your career, as a scientist? Most importantly, having access to large data-bases gives a scientist international stature. In my field of interest, complex genetics, we need very large sample sizes. Currently, I collaborate with more than 24 international groups. Together, we can answer scientific questions requiring samples of or more. So, being able to contribute LifeLines data made me an attractive scientific partner for top research groups all over the world. This has been a huge stimulant for my personal career as a scientist: collaboration with a lot of groups is challenging but it is also highly inspiring. An efficient organization can result in more publications, we were able to generate high impact results so they are cited a lot. Pim van der Harst (1977) started his career as a researcher during his cardiology training, after finishing medical school cum laude. He is now an Associate Professor in Cardiology specializing in interventional cardiology and complex genetic research at the University Medical Center Groningen. He received several prestigious grants including LifeLines data in his research proposals, and was awarded scientific prizes for excellence both within The Netherlands and abroad. Co-morbidity is a significant problem in heart disease 11

14 Access to LifeLines The core of the LifeLines project consists of dedicated data collection and biological sample storage, including genetic samples Application Process Researchers who are interested in utilizing LifeLines data, biomaterial or the infrastructure may apply for access by submitting a short proposal to the LifeLines Research Office describing their research aim and request. Research Proposal Any researcher, including PhD students and post-doctorate researchers, can apply for data or biomaterial, when they are connected to a department or institution with the competence to carry out the proposed research project to term. LifeLines also welcomes other public and private partners. The proposal must fit within the concept of Healthy Ageing. LifeLines Scientific Board reviews all proposals to ensure scientific quality, to avoid duplicates of running proposals and to confirm it fits into the Healthy Ageing theme. A feasibility check is performed on application for the LifeLines sample and infrastructure. When a proposal is approved, the researcher will receive a contract and the exclusive right to use the data for a pre-determined period of time. Data is released within a remote system (LifeLines workspace) running on a high performance computer cluster. In case the researcher asked for additional data collection within LifeLines, a member of the LifeLines Research Office will be dedicated to the project and work in close collaboration with the researcher. Data and biomaterial can be used for scientific research only. Scientific results become publically available. Applications are published on the LifeLines website in consultation with the researcher and publications with LifeLines data or biomaterials are listed. LifeLines invites researchers who are investigating data or biomaterial to participate in the LifeLines research community to find additional information and documentation. More importantly, the research community stimulates researchers to share experiences and ideas and serves as a platform for discussion. RESEARCHER Research Proposal LIFELINES Scientific review by Scientific Board Internal review by LifeLines Sample/data release For full guidelines for access to the described services, please visit Costs All data and materials for scientific research are provided on a fee-for-service base. LifeLines recommends that researchers request a quotation of estimated costs before applying for research grants and subsidies. 12

15 Bennard Doornbos MD/PhD, studies the impact of low grade inflammation (hscrp). Low grade inflammation is related to general health behavior, and modern diseases such as cardiovascular disease, and to the speed of ageing in general. We found that it is also associated with the prevalence of depression. We also found that Lifestyle, and more particular the Body Mass Index of depressed patients explains a significant part of this relationship. With the follow-up data we will investigate speed of ageing in depression. The LifeLines data structure made it possible to investigate comorbidity at different levels of disease in individual patients. 13

16 Through LifeLines leading role in biobank networks, researchers will be able to use pooled data from different cohort and biobank studies and gain access to the large sample sizes needed to investigate questions in multifactorial diseases LifeLines Extensive Networks Biobank Networks Public-Private Partnerships

17 As a center of expertise in biobanking, LifeLines takes part in a number of strategic alliances, national and international biobank networks and research collaborations. Through these networks LifeLines established itself as one of the world leaders in the science of biobanking, as well as contribute to the advancement of public-private partnerships. Biobanking and Biomolecular Resources Research Infrastructure Matching data collection will be achieved through the development of harmonization and standardization tools, implementation of these tools and demonstration of their applicability. LifeLines actively participates in BBMRI-NL, a collaboration of all population-based and diseaseoriented Dutch Biobanks, in projects devoted to biomarkers, gene expression, harmonization and standardization, and nutrition. The future aim is to integrate BBMRI-NL with the Parelsnoer Institute and LifeLines, to create one, common, coherent biobank with high-quality clinical and molecular data and optimized accessibility. This Dutch Biobank Hub will become part of BBMRI-ERIC. Active large European population studies: CHRIS/MICRA (Bolzano, Italy), Estonian Biobank (Tartu, Estonia), FINRISK (Helsinki, Finland), KORA (Munchen, Germany), HUNT (Trondheim, Norway), LifeGene (Stockholm, Sweden), NCDR (Leicester, UK), Prevend (Groningen, Netherlands), SHIP (Greifswald, Germany), UKbiobank (Oxford, UK). Biobank Networks LifeLines is an active partner in P3G (world-wide), the European Research Infrastructure Consortium BBMRI-ERIC, and takes a frontline position in BioShare: a consortium of leading large-scale population biobanks and international researchers from all domains of biobanking science. With its expertise in largescale bioinformatics solutions, LifeLines is active in several European biomedical sciences research-it infrastructures, joined in BioMedBridges. Finally, as the largest sample collection in the Netherlands, LifeLines is an important member of the European society for the collection and storage of biological materials ESBB. Public-Private Partnerships As a partner in TI-Pharma s aim to improve the development of socially valuable medicine, LifeLines participates in the Mondriaan project in which data from existing databases and registries in The Netherlands will be pooled for statistical analyses. Also, LifeLines has joined TI- Food and Nutrition with specific projects related to nutrition and multifactorial diseases. Additionally, within the Netherlands Consortium for Healthy Ageing (NCHA) LifeLines focuses on (epi)genomics in age-related diseases. 15

18 Interview Judith Rosmalen We need data including information at different levels: from genetic to environmental and everything in between Crying: did you ever wonder why people think you may be sad or angry, when your eyes are making the well-known wet salty drops of water? Probably not. In some somatic symptoms, it is perfectly clear that mind and body interact, but in others this interaction is under debate. These so-called functional somatic symptoms are a challenge for all medical professions. How a large data-base such as LifeLines can shed different light on these mysterious symptoms. You used the data that LifeLines collected about functional somatic symptoms. What are they? Functional somatic symptoms are those somatic symptoms that cannot be sufficiently explained by measurable physical abnormalities. For example, we looked at syndromes such as Chronic Fatigue Syndrome, Irritable Bowel Syndrome and Fibromyalgia. This type of symptoms is believed to be the result of psychological distress. We do indeed find higher stress levels in patients with functional somatic 16

19 PHOTO: HENK VEENSTRA symptoms but we don t know what was the cause and what was the effect. Do patients become more distressed as the result of having an unexplained condition and the possible misunderstanding of the medical practitioner, or is pre-existing psychological stress influencing the development of the symptoms? As usual, the truth lies somewhere in between. We d like to find out where. You need large numbers to be able to investigate such complex and interacting issues? Indeed. LifeLines enabled us to perform a study including three types of Functional Syndromes, including 94,516 participants. The large number of LifeLines participants is obviously an attractive aspect of using LifeLines data. We worked at another interesting and longstanding medical debate: Previous work suggested that the medical profession should regard disorders, such as Chronic Fatigue Syndrome, Irritable Bowel Syndrome and Fibromyalgia, as part of the same syndrome. By some professionals they are seen as a heterogenic group of patients: some patients may emphasize muscle aches and others fatigue, but all with a similar psychological etiology. The large patient sample showed us that the truth is more complex. Your data did not confirm this one size fits all image of patients with functional somatic disorders? The data taught us that the number of participants with all three syndromes is over 33 times higher than would be With the large numbers, we can investigate the more subtle differences between individuals expected by chance. This suggests that the three syndromes do share risk factors. On the other hand, patients also show important differences. For example, although all syndromes affect woman more often than men, this is much more the case in fibromyalgia compared to Chronic Fatigue Syndrome. Also, the different syndromes are associated with different types of somatic and psychological complaints. What are the implications? Should we treat these patients differently? Well, we plan to use the LL follow-up data to investigate what causes the overlap, and the differences. That s what s interesting about the LifeLines data: a broad and longitudinal data base offers the opportunity to investigate the symptoms at multiple etiological levels. For example, we can identify (shared) risk factors at genetic, hormonal or other somatic levels. We can also look at social or heath care factors that may contribute to the chance that functional somatic symptoms become chronic. And, the consequences, what does it mean to have these symptoms, in terms of psychological well-being, socio-economic status or the ability to work, are important to understand. If we understand the specific issues that influence these symptoms, we can tailor medical care to the individual patient. How was the process to gain access to the LifeLines data? Did you need to meet certain scientific standards? LifeLines applies broad and flexible criteria; all researchers can apply for a publication proposal. The key to a LifeLines publication is solid scientific argumentation, similar to grant proposals. We explained the scientific importance of including the questions about the prevalence of the functional somatic syndromes that we are now preparing a publication on. Researchers can either contact LifeLines with a proposal to include additional data collection, or they can take a look at the existing data-base. I recommend young researchers to look at the additional value of existing LifeLines data and to include its fee in their grant proposals. That is the moment when the fee for a publication using LifeLines data can easily be incorporated within the grant proposal. Judith Rosmalen (1971) studied both Medical Biology and Psychology. She is now a Professor in Life course Epidemiology of affective disorders, specialized in Somatization Disorders working at the Interdisciplinary Center Psychopathology and Emotion regulation at the University Medical Center Groningen. She is the president of EURAS- MUS (European Research Association for Somatoform and Medically Unexplained Symptoms), a European research network aiming to study the etiology of somatization. 17

20 LifeLines Scientific Organization LifeLines takes a frontline position in the science of biobanking Members Scientific Board Prof P. (Paul) de Bakker, Genetics - UMCU Dr U. (Ute) Bültmann, Social Medicine - UMCG Dr J.M. (Marianne) Geleijnse, Human Nutrition - WUR Dr P. (Pim) v.d. Harst, Cardiology - UMCG Prof G.H. (Gerard) Koppelman, Pediatric Pulmonology - UMCG Prof J.G.M. (Judith) Rosmalen, Psychiatry - UMCG Dr E.F.C. (Liesbeth) van Rossum, Endocrinology - EMC Prof H. (Hauke) Smidt, Microbiology - WUR Dr M.A. (Morris) Swertz, Bioinformatics - UMCG Chief Scientific Officer (Chair of the Scientific Board): Prof R.P. (Ronald) Stolk, Epidemiology - UMCG Coordinator Research Office (Secretary of the Scientific Board): Dr S. (Salome) Scholtens, Epidemiology - UMCG Monitoring and Security LifeLines is permanently aiming to improve biobanking worldwide by researching its own data and establishing professional guidelines, policies and protocols for large study populations. As such it takes a leading position in many international collaborative networks. LifeLines has developed expertise in ethics and privacy rules, the organization of collecting and storing large quantities of biomaterials and data and the guaranteed quality of the data warehouse. LifeLines upholds high quality standards and expects ISO certification next year. The LifeLines scientific progress and anchoring are monitored and secured by: Scientific Board The national Scientific Board consists of Principle Investigators who have the responsibility: to secure the scientific quality and utility of the collected data to review submitted research proposals for use of LifeLines data to build and facilitate interdisciplinary collaborations to form (inter)national research networks for LifeLines to apply for research grants and other funding LifeLines Research Office The Research Office is the researchers gateway to the LifeLines data and the main point of contact throughout the entire process of application, analyses, publication and follow-up. Applications are processed by the Research Office and monitored on release, additional data requests, and publications. When additional data is requested, the Research Office takes care of its implementation in the LifeLines infrastructure or linking to external data sources. As its staff is very familiar with the LifeLines data, the Research Office offers advice on the use of the data and statistical analyses, or refer to other experts in a specific research field or methodology. Additionally, the Research Office guards and supports participation in (inter)national research collaborations and biobanking networks and concomitant enrichment of the LifeLines data collection and economic value creation. LifeLines Research Office works in close collaboration with the Chief Scientific Officer and the Scientific Board. 18