Clinical Epidemiology

Prof. dr. M.A. Ikram

This research line focuses on the etiology of neuro-degenerative and cerebrovascular diseases, including dementia and Alzheimer’s disease, Parkinson’s disease, ischemic stroke, hemorrhagic stroke, migraine, white matter pathology, microbleeds, and polyneuropathy. The research utilizes a multimodal approach to study causes, determinants, and prognosis of these disease. A particular focus is on interacting pathologies, including vascular disease and neurodegenerative diseases. The research revolves around three main areas: 1) biomarkers, which includes genetics, serum markers, and metabolomics; 2) neuroimaging, which includes conventional as well as advanced magnetic resonance imaging (MRI) (e.g. diffusion tensor imaging, fMRI, perfusion imaging); and 3) subclinical signs and symptoms, including cognition, gait, and activities of daily living.

Research is carried out at the Department of Epidemiology in the setting of the Rotterdam Study and Rotterdam Scan Study. Major collaborations are set up with the departments of Neurology, Radiology & Nuclear Medicine, Neurosciences, Medical Informatics, Internal Medicine, as well as external national and international partners.

Prof. dr. Bruno H.C. Stricker

The focus is on intended effects of medications, and the effects of medication use under common circumstances in large populations. There are several drug-related research projects in the Rotterdam Study, a large prospective cohort study that is being conducted since 1990 to investigate cardiovascular, locomotor, neurological, and ophthalmological diseases.

Dr. Maryam Kavousi MD PhD FESC

Cardiovascular disease is the most common chronic illness in both developed and developing countries, causing approximately one-third of the total deaths worldwide and the greatest impact on morbidity. The Cardiovascular Disease Epidemiology group aims at interdisciplinary research across several established disciplines within the group and integrates knowledge on all aspects of the cardiovascular disease; including biology, behavior and lifestyle, imaging, risk prediction, prevention, treatment, and prognosis.The large population-based Rotterdam Study, as well as the long-standing collaborations with a number of other large cohort studies around the world, provide a rich environment for the conduct of cutting edge research. Within the group, the following main research teams, working closely and in parallel, are designed to cover the whole spectrum of research on cardiovascular disease:

Subtheme 1: Biomarkers for cardiovascular disease

Within this discipline, current advances in molecular biology and genetics including genomics, epigenomics, transcriptomics and metabolomics are exported from the laboratory to the epidemiology field, allowing a molecular epidemiologic approach towards investigation of clinical and pre-clinical cardiovascular disease. This working theme aims to recognize the importance of molecular and genetic approaches to cardiovascular disease and most importantly, utilize this knowledge to conduct prevention and treatment research that directly improves the health of individuals.

Subtheme 2: Lifestyle factors and primary prevention

Existing and developing knowledge regarding risk factors for cardiovascular disease, especially modifiable risk factors, suggest that it may be possible to curtail the explosion of global disease. To this end, this work theme is focused on evaluating the role of lifestyle factors and interventions for preventing cardiovascular disease among healthy populations.
The research focuses on the individual as well as the collective contribution of lifestyle factors; including physical activity, dietary factors, alcohol consumption, smoking habits, wellbeing, sun exposure and sleep, to the prevention of cardiovascular disease. It also aims to address the lacking knowledge on the interaction of lifestyle factors with genetic, metabolic, and inflammatory markers as well as medications.

Subtheme 3: Cardiovascular risk prediction

Clinical decision making for detection, management and prevention of cardiovascular disease relies on accurate identification of individuals at risk of developing the disease. This research team, working closely with the departments of public health and biostatistics, appreciates the role of emerging markers in cardiovascular disease risk prediction and aims on augmentation of the standard cardiovascular risk scoring systems with novel measures. Enhancements in ascertaining the risk status of individuals for developing cardiovascular disease secure windows of opportunities that could permit early preventive interventions and personalized care.

Subtheme 4: I Cardiovascular imaging (Dr. Daniel Bos)

Cardiovascular imaging research contributes to the understanding of the natural history of cardiovascular disease and the processes leading to the progression and/or stabilization of the disease, as well as the assessment of disease burden and therapeutic efficacy. This research team within the cardiovascular disease epidemiology group works in close collaboration with the departments of cardiology and radiology and focuses on the application of imaging technology to cardiovascular disease prevention. Imaging techniques that are used are CT (vascular calcification, epicardial fat, liver fat), MRI (carotid atherosclerosis) and ultrasound (carotid plaque). Current research projects within this discipline are focused on evaluating associations between various risk factors and vascular structure and function, as well as evaluating the role of non-invasive assessment of sub-clinical atherosclerosis and endothelial function in cardiovascular risk prediction.

Subtheme 5: Cardiovascular disease among women

Although cardiovascular disease continues to be the leading cause of death for both women and men, there are substantial sex and gender differences in the etiology, prevalence, burden, and prognosis of different cardiovascular diseases. Understanding sex- and gender-specific aspects of cardiovascular disease will serve to improve the health of both women and men. This theme focuses on novel and unique aspects of cardiovascular disease in women and gender differences as they relate to clinical practice in the prediction, prevention, diagnosis, treatment, and prognosis of cardiovascular disease. This research team within the cardiovascular disease epidemiology group works in close collaboration with the departments of gynecology and cardiology.

Subtheme 6: Diabetes mellitus

Type 2 diabetes is a serious and common chronic disorder resulting from a complex interplay between genetic, epigenetic, and environmental factors. Within this discipline, contribution of traditional and novel risk markers representative of different pathophysiological pathways to type 2 diabetes is studied. The research covers the whole spectrum of type 2 diabetes; disease development, progression (from normoglycemia to pre-diabetes, to type 2 diabetes, to initiation of insulin therapy), and complications. This will allow for early detection of prediabetes and diabetes, as well as lifestyle and therapeutic interventions as the overarching objectives in preventing and managing type 2 diabetes.

Dr. Annemarie I. Luik

Depression, anxiety and disturbed sleep are leading causes of the global disease burden worldwide. In the past, researchers identified psycho-social risk factors but we now realize that most psychiatric disorders are the result of an interplay between functional and structural brain changes, genes, cognitive and psychological processes and social factors. Our research on common psychiatric disorders is embedded in the Rotterdam Study and Generation R. Main areas of interest are depression, anxiety and sleep, but we also study complicated grief, alcohol abuse, sexuality and happiness. Our aim is not only to explain how biological or social factors cause psychiatric disorders, we also investigate how psychiatric problems or diseases impact on quality of life physical health. Some examples of research questions we are addressing:

• How do symptoms of depression, anxiety, poor sleep and social health cluster? Using clustering and network approaches we take on a more transdiagnostic approach to psychiatric diseases and symptoms.
• Do changes in cortisol and stress, e.g. HPA-axis, reactivity affect sleep? We monitored sleep using both actigraphy and polysomnography and are one of the first to be able to assess these associations over long periods of time.
• Do first-ever and recurrent depression have the same causes? We collected unique data of more than 5000 persons over 10 years with continuous monitoring of depressive symptoms to increase our understanding of depression.
• How is poor sleep related to brain health across the life course? Using brain imaging, questionnaires, actigraphy and polysomnography we aim to disentangle the association between sleep and brain health in children and adults, For this work we collaborate with the population imaging and neuro-epidemiology groups.

Prof. dr. Vincent W.V. Jaddoe, coordinator,

The Generation R Study is a large population-based cohort study from fetal life until young adulthood in 10,000 children. The Generation R Study is a collaborative project in which several departments in the Erasmus MC participate. The study is designed to study growth, development and health in a contemporary population-based multiethnic cohort of urban children from fetal life until young adulthood. The study focuses on four primary areas of research: (1) growth and physical development; (2) behavioral and cognitive development; (3) diseases in childhood; and (4) health and health care for pregnant women and children. Special interest in these areas of research is on identification of early causal pathways leading to both normal and abnormal growth, development and health in childhood and adulthood.

The general aims are:

• To describe normal and abnormal growth, development and health from fetal life until young adult-hood in a multiethnic population-based cohort;
• To identify biological, social and environmental determinants of normal and abnormal growth, development and health from fetal life until adulthood;
• To examine the utilization and effectiveness of cur-rent strategies for prevention and early identification of groups at risk.

Eventually, this study will contribute to the development of strategies for optimizing health and health care for pregnant women and children.

An extensive data and biobank has been generated. With an integrated strategy of basic, clinical and epidemiological research various research questions are addressed focused on growth, development and health from fetal life to young adulthood. MSc student are actively participating in one of the 4 main research programmes in the Generation R Study (www.generationr.nl). A few subthemes are mentioned below.

Subtheme 1: Early growth, obesity and cardiovascular development

Prof. dr. V.W.V. Jaddoe, Prof dr. E.A.P Steegers

This research is embedded in The Generation R Study and focused on envrionmental and genetic exposures related to fetal and postnatal growth, early cardiovascular development, insulin resistance en obesity. We also study risk factors of pregnancy complications in mother and child, such as preeclampsia and preterm birth. Research is performed in closed collaboration between the departments of Pediatrics, Epidemiology, Obstertrics, Pediatric Cardiology and Pediatric Nephrology.

Examples of research topic are:

• Development of growth curves
• Materna life style habits in relation to pregnancy complications
• Genetics of fetal and postnatal growth
• Maternal and childhood nutrition in relation to cardiovascular and metabolic development
• Biomarkers of preeclampsia and pregnancu induced hypertension

MSc student are actively participating in one of the research projects, actively participate in the research Group (data collection, cleaning, scientific meetings) and normally procude one to two papers that will be submitted for publication.

Subtheme 2: Early determinants of respiratory morbidity

Prof. dr. J.C. de Jongste, Dr L. Duijts.

‘Generation R’ is a multidisciplinary project, aimed at recruiting a 10.000 children birth cohort in Rotterdam, with follow-up from the first trimester of pregnancy until 20 years of age. The project wants to establish prospectively the importance of prenatal and early life events for later health, to ultimately improve children’s health and education by defining factors which affect growth and development, and determine risk of disease in order to stimulate preventive strategies.

The prevalence of chronic respiratory symptoms among children of various ethnic minorities in the Netherlands is unknown. In major North-American cities the prevalence of childhood respiratory disease including asthma and allergy is increasing, especially in non-caucasian children. There is evidence that ethnic differences in prevalence cannot only be explained by differences in socio-economic class. In Europe, several birth cohort studies have addressed respiratory morbidity during the first years of life. These have focused on known risk factors for respiratory morbidity, including socioeconomic status, exposure to allergens and pollutants, family history of allergy and/or asthma, and examined relationships with respiratory symptoms. However, few have focused on ethnic differences. In Swedish and German studies differences in atopic disease prevalence were reported between Western European and Turkish immigrant children, suggesting that environmental and genetic factors are involved which may affect the risk of infection, allergy and asthma in different ethnic groups.

In the Netherlands, the ongoing PIAMA study follows a large birth cohort. A relatively high prevalence of respiratory symptoms was found in non-Dutch ethnic groups, which could be largely attributed to socioeconomic differences, suggesting that environmental factors had strong impact on respiratory morbidity in the first 2 years.

However, numbers were small and biased, as only Dutch questionnaires were used. No epidemiologic birth cohort study has specifically been designed to include different ethnic groups by approaching them in their own language, and evaluate the differences in symptomatology together with biological, medical, psychosocial and environmental factors in order to establish and understand differences in respiratory morbidity, especially asthma, and allergy between ethnic groups living in the multicultural urban society.

Question:

Are respiratory morbidity and allergy different between ethnic groups and, if this is the case, can differences be explained by pre- and/or postnatal environmental factors? The project is focused on describing respiratory and allergic morbidity of the Generation R cohort during the first 2 years of life.

Question/aim:

• This project aims to address the impact of ethnicity and environmental factors on respiratory morbidity in the first 2 years of life by answering the following questions:
• Is ethnicity a risk factor for respiratory morbidity and allergy in the first two years of life?
• Do medical consumption (drug prescription, visit to the general physician, hospital admission), perception of disease and quality of life of infants and preschool children with chronic respiratory symptoms and/or allergy differ between ethnic groups?
• To what extent can environmental pre- and postnatal factors explain differences in respiratory morbidity and allergy between ethnic groups?

For a NIHES fellowship, a suitable question will be selected For a NIHES fellowship, a suitable question will be selected and analysis performed of existing databases, in close co-operation with the dept. of pediatrics, epidemiology and public health of the Erasmus MC.

Subtheme 3: Immunological and bacterial determinants of nasopharyngeal carriage of opportunistic pathogens and infections in young children

Prof. dr. H.A Moll, Dr. M. van Zelm, Prof. H. Hooijkaas

After infection, T and B lymphocytes are able to maturate into highly specific memory lymphocytes, which is the basis for adaptive immunity. The adaptive immune system matures in the first years of life through host pathogen interactions. However, it is unclear how the adaptive immune system in young children is shaped to create highly specific immunity to a wide variety of pathogens. Although the immune system is able to generate strong immunological responses, complete eradication of pathogens is not always achieved.
Several viruses are known to evade clearance and persist in a dormant state. In latency, the virus is not detectable anymore in serum, but antibodies against these viruses are. Common persistent viruses are Epstein-Barr virus (EBV) and Cytomegalovirus (CMV). The prevalence of persistent CMV and EBV infections is estimated to range from ~50% in children to >90% in adults. Reactivation of these viruses when immunity is suppressed can result in major complications, e.g. in transplantation settings, suggesting that these viruses can only be controlled by a constantly active immune system. We hypothesize that this constant viral pressure puts a heavy load on the immune system, and will affect normal immune maturation. One parameter that reflects the maturation of adaptive immunity is the extent of differentiation of lymphocytes in the peripheral blood. We hypothesize that persistent viral infections have adverse effects on the diversity of the broad immune repertoire, thereby impairing immunity to other pathogens.

The aim is to:

• Study determinants of CMV and EBV infection in children at 5 years of age;
• Study the buildup and diversity of the immature adaptive immune system by studying the phenotypic differentiation of lymphocytes in children with and without persistent infections with EBV or CMV at 5 years of age.
• Study the consequences of the diversity of the adaptive immune system for atopic and immune mediated diseases
• Determine how development, diversity, and reactivity of the adaptive immune response in healthy and allergic children, are affected by the intestinal microbiota.

Clinical and scientific relevance for the future: This project will contribute to the detailed understanding of the development of the immune system and their consequences for atopic and immune mediated diseases in children.

Subtheme 4: Behavioral and cognitive research in young children

Prof. dr. Manon H.J. Hillegers, Dr. Pauline W. Jansen

Whereas most somatic disorders are quite rare, behavioural and learning disorders in children are frequent. About one in ten children will develop a mental health disorder and many more have behavioural or cognitive problems that are a burden to child, families and society. Behavioural problems can be caused by social factors (e.g. bullying or poverty), psychological factors (e.g. bad parenting or poor emotion recognition) and biological factors (e.g. genetic variation or altered stress hormones). Aetiological research has demonstrated that many child psychiatric disorders are neurodevelopmental in origin, i.e. they have their onset early in life and affect the functioning of the nervous system. Furthermore, child psychiatric research has been leading the field of gene-environment interaction studies.
This understanding has guided the behavioural and cognitive research in Generation R. We are thus investigating the importance of fetal development for behaviour and cognition later in life, and have assessed neurodevelopment with brain-ultrasound, neurological examinations, and will soon start MRI imaging.

Moreover, we are conducting genome wide analyses and candidate studies to detect genetic risk factors and vulnerabilities. Together with several EUR and external partners we have introduced many innovative child assessments, which are unique to large-scale behavior studies. These include the Strange Situation Procedure, HOME environment assessment, executive function, parent-child interaction tasks or tasks of moral development.
The topics and possible themes for research in Generation R cover a wide area; selected but prototypical questions addressed in the coming years include:

• Do low thyroid hormone or vitamin levels in pregnant women cause cognitive problems in the offspring? (Neurodevelopmental research)
• Does father-child interaction matter in respect to the emotion development of the child? (Med Psychology)
• What do teacher, father and 5-year child self report add to maternal report of behavioural problems? (Methods)
• Do daycare, bullying in kindergarten, television watching or unstructured parenting affect certain children predisposed to behavioural problems? (Social Psychiatry)
• Are altered cortisol secretion patterns cause or consequence of behavioural problems? (Psychobiology)
• Does prenatal cannabis exposure affect the brain development? (Psy. Imaging)
• Can we identify the genetic basis of child resilience to family adversity (Psy.Genetics)

The department of dermatology (Erasmus MC) is the largest training hospital for dermatology in The Netherlands. The three main research themes are: (1) oncology, (2) inflammation and (3) phlebology. The research focuses on common skin diseases that have a large impact on both patients and society. Since we study common diseases, most of our research is translational, and involves patient data.

The epidemiology and clinical research group supports the three research focus points of the department of dermatology. This research line collaborates closely with other Erasmus MC departments such as Epidemiology and Public Health. We work with large existing datasets including national cancer registries (IKNL), national pathology database (PALGA), pharmacy based databases (PHARMO RLS Network) and are integrated in the Rotterdam Study. In addition to database research, we are involved in many clinical studies and trials in the field of dermato-oncology, psoriasis and varicose veins. Together with Public Health and department of primary care we are investigating the possibilities of shifting care to the GP’s and assess patients preferences and its economic impact.

In addition to these health science activities, the department has an experimental research branch focused on dermatological immunology and inflammatory pathways in psoriasis. The Center for Optical Diagnostics and Therapy (CODT) is also part of the department of dermatology. Its members are investigating Raman, reflectance, and fluorescence spectroscopy for the diagnosis of skin diseases and the therapeutic use of light in translational research on photodynamic therapy (PDT).

Subtheme 1: Skin cancer

A. Prevalence, incidence, mortality and survival of cutaneous malignancies in The Netherlands and Europe.

Dr. Loes Hollestein, drs. Joris Verkouteren, dr. Luba Pardo, Prof. dr. Tamar Nijsten

The basic of epidemiology is measuring the frequency of disease occurrence. The Dutch cancer registry is one of the few population based cancer registries that includes basal cell carcinoma (BCC) and is one of the most reliable sources on the incidence of BCC worldwide. Together with the department of Public Health and the cancer registries, we have a long track record in this specific field. Recently, we have studied the occurrence of multiple skin cancers emphasizing the concept of field cancerization. We are approaching cancer survivors for more detailed information to expand our qualitative research activities including establishing a skin cancer specific QoL questionnaire.. In addition, focus on health services research among skin cancer patients at the different levels of care in The Netherlands. We investigate the diagnostic, therapeutic and follow up interventions and to do so, we use claims data, cancer registry data and IPCI data.

Linking data from other European cancer registries allows us to compare incidences across Europe and detect trends in incidence, mortality and survival by cancer type, stage, etc.

Aims:

• To study incidence, prevalence and trends of all cutaneous malignancies in The Netherlands.
• To compare trends in incidence and mortality of melanoma and nonmelanoma skin cancer across European countries.
• To study survival of melanoma patients in a population-based setting
• To study the association of risk of skin cancer with other cancers

Methods: The Dutch cancer registry (IKNL) has collected tumor data since 1989 and has shown to be highly reliable. The IKNL collects all skin malignancies including BCC that is registered in one of four regions (IKZ). In the network of cancer registries, datasets from different countries are merged and can be compared and studies with regards to incidence, age, tumour characteristics (morphology, topography), treatment and for melanoma, co-morbidity at the moment of diagnosis. Follow-up for vital status is available and specific studies can be designed to obtain additional patient information.

B. Prevalence of skin cancer and its associated (genetic) risk factors.

Dr. Luba Pardo, drs. Joris Verkouteren, Dr. Leonie Jacobs, dr. Loes Hollestein, Prof. dr. Tamar Nijsten

Of the approximately 35,000 Dutch citizens that develop a basal cell carcinoma (BCC) annually, a substantial proportion develops multiple BCCs in the years after their first BCC. A meta-analysis of studies from the USA and Australia suggest that about 40% of BCC patients will have one or more BCCs after their first BCC. The likelihood to develop another melanoma after having been diagnosed with a first is less well documented.

Some relatively smaller studies suggest this is about 5%. Several high-penetrance loci have been identified for skin cancer. In addition to these mutations, recent genome-wide association studies (GWAS) have identified a number of common genetic variants associated with the development of sporadic skin cancers. The identification of high risk patients is clinically relevant because it may affect the follow up regimen after diagnosis. Also, studying high risk skin cancer patients in detail may increase the understanding of carcinogenesis.

Aims:

• To study incidence of multiple basal cell carcinoma.
• To study incidence of multiple melanomas
• To identify genes associated with the development of skin cancers and premalignancies
• To study environmental and patient-related factors and potential gene-environment (GE) interactions related to skin cancer

Methods: To study the incidence of multiple skin cancers in large databases, we use the national pathology database (PALGA) and the national cancer registry (IKNL). Both these datasets allow us to estimate the frequency of occurrence of multiple skin cancers and assess whether age and gender are related to a higher risk of developing more than one skin cancer. For a detailed risk factor analysis, the approximately 2,000 people with skin cancer in the Rotterdam Study are analyzed. In addition to patient and tumor characteristics and environmental exposures, we are interested in the genetic component of developing (multiple) skin cancers. Therefore, GWAS and candidate-gene approaches and pathway analysis will be performed in collaboration with the Harvard cohorts and deCODE.

C. Risk factors of intrinsic and extrinsic skin aging

Drs. Leonie Jacobs, Drs. Merel Hamer, Dr. Fan Liu, Prof. dr. Manfred Kayser, Prof. dr. Tamar Nijsten

Skin changes such as wrinkling, hyperpigmentation and hypervascularity and skin sagging around the eys and cheeks are part of skin aging. The effect of patient characteristics such as age (including hormonal status), gender and body mass index, sun exposure and smoking status are well documented risk factors for more pronounced skin aging. Skin aging is not only a cosmetic concern, but is also a risk factor for skin cancer development. Moreover, loss of cutaneous elasticity (i.e., skin wrinkling and sagging) may be a predictor of more systemic aging. Little is known about the genetic contribution to skin aging and whether it is associated with other diseases.

Aims:

• To study the association between classic (life-style, dietary, environmental, and hormonal) risk factors and different components of skin aging (wrinkling, pigmentation spots and teleangiectasia)
• Identification of common variants associated with skin aging
• Investigate the genetics of perceived age.

Methods: This research theme was part of Netherlands Consortium of Healthy Aging (NCHA) and at the Erasmus MC it is a collaboration between Erasmus MC’s dermatology and genetic identification and LUMC. The data used is primarily derived from the Rotterdam Study, but also from other international genetic consortia interested in these phenotypes. Different aspects of skin aging are scored by dermatologists on thousands of standardized 3 dimensional photographs. Also, biological, calendar and estimated age will be assessed. These skin-related outcomes will then be used to identify classical risk factors including a food-frequency questionnaire and genetic polymorphisms associated with (components of) skin aging.

D. Impact of skin cancer on patients’ lives.

Prof. dr. Lonneke van der Poll, drs. Rik Waalboer, dr. Loes Hollestein, Prof. dr. Tamar Nijsten

Except for a relatively small proportion of melanoma patients, skin cancer (i.e., basal cell carcinoma, squamous cell carcinoma) is a non-life threathening disease. In contrast to other solid and hematological malignancies, the long term (treatment induced) sequelae after the surgical removal of skin cancer are fairly mild. Nevertheless, most skin cancers are located in the face and scars after surgery may have cosmetic and functional consequences. Moreover, patients’ lives are affected by a diagnosis of skin cancer. The have an impaired health related quality of life (HRQOL) often due to sun avoidance issues, anxiety to develop other cancers and being anxious of the skin of their family and loved ones.

Aims:

• Estimate the impact of different skin cancer on patients’ lives.
• Estimate the trend of quality of life impairment in melanoma patients over time
• Self knowledge of patients’ diagnosis.
• Create and validate a skin cancer specific QoL questionnaire (BASIQOL)

Methods: This is primarily a postal survey to cancer survivors registered in the Dutch cancer registry. However, a new skin cancer specific HRQOLL instrument needs to be developed via the established methodology including focus groups. The self-completed questionnaire includes items on patient characteristics, validated disease specific and generic HRQOL instruments, a EORTC questionnaires assessing level of information about patients’ cancer and very specific and practical questions relevant to patients with a prior skin cancer.

E. Drug use and skin cancer risk.

Dr. Loes Hollestein, Prof. Ron Herings, Prof. dr. Bruno Stricker, Prof. dr. Tamar Nijsten

Medication use can influence the risk of several malignancies including skin cancers. Pharmacological companies try to monitor potential adverse effects (pharmacovigilance), but medications can also have a chemopreventive effect on (skin) cancer. Chemoprevention in skin cancer is not yet as well documented as for colon cancer and other solid cancers. For now, acitretin is the only available drug that lowers the risk of developing skin cancer.
Other interesting drugs are aspirin, NSAIDs and statins because their risk profile is well known, they have other important health effects and observational studies suggest that they may be effective in skin cancer. In addition to cancer occurrence, drug exposure might influence progression of cancer.

Aims:

• investigate the association between prescription medication and skin cancer development.
• investigate potential effects of the use of certain medications on progression and mortality of melanoma

Methods: In the southeastern part of the Netherlands, there is an area where data on prescription medication use is available from the PHARMO database and detailed information on cancer diagnosis and prognosis from the Eindhoven Cancer Registry.
This linkage of two large databases can be used to study a multitude of questions related to the above mechanisms.

F. Clinical research in the treatment of skin cancer

Dr. Renate van den Bos, dr. Gerwin Puppels

The department of dermatology has a longstanding experience in the treatment of patients with skin cancers. We perform many surgical procedures including micrographic Mohs surgery (MMS) in which we are a centre of excellence. The department develops the MMS technique and expands the types of skin cancer that can be treated with MMS. All the patinets treated with digital MMS are entered in a database which is suitable for research as well as clinical trials in skin cancer patients. The clinical research varies from prospective comparative trails to open case series. Nonsurgical treatments such as PDT are also subject of research at our department in developmental stages as well as in comparative studies.

Aims:

• Innovation in skin cancer treatment
• Optimize patient care and surgical techniques
• Development of new nonsurgical treatments.
• Evaluate existing management strategies and treatments (such as Mohs surgery)

Methods: Retrospective and prospective clinical studies as well as preclinical studies are being done to improve surgical techniques with a focus on MMS. The existing database of MMS treated patients (>1,500) is a source for many interesting study objectives. Besides are we involved in the development, use and research in new medical devices and bandage equipment, an example is the plaster we can use instead of using stitching techniques.
Clinically, photodynamic therapy using ALA is routinely used as a treatment for actinic keratosis, squamous cell carcinoma in-situ and basal cell carcinoma. We are investigating the use of light fractionation to enhance efficacy and using low intensity illumination to reduce pain and enhance patient satisfaction.

We are involved in a number of large scale randomized trials to assess the efficacy and cost effectiveness of PDT. We are also investigating the use of PDT using porphyrin pre-cursors and pre-formed photosensitizers in the skin of the genitourinary system.

G. Raman spectroscopy and skin cancer

Dr. Gerwin Puppels, dr. Peter Caspers

Melanoma is the most lethal skin cancer. Worldwide 200.000 patients are diagnosed with cutaneous melanoma each year. If melanoma is recognized in an early stage patients can be cured by complete surgical resection with a 95% 5-year survival rate. Diagnosis at a later stage results in drastically lower survival rates.

Aims:

To development instrumentation and methodology for objective real-time identification of suspicious pigmented skin lesions using Raman spectroscopy.

Methods: Raman spectroscopy is a non-invasive method to obtain detailed information about molecular changes in tissues by illuminating the tissue with laser light and analyzing the light that is scattered back.

The CODT houses state-of-the-art Raman equipment for in vivo and in vitro Raman measurements on tissues. The equipment will be used to create an annotated (clinical evaluation, histological pathology) database of Raman spectra of suspicious pigmented lesions. This database will be used for the development and validation of diagnostic algorithms.

H. Optical Spectroscopy and skin (pre-)malignancies

Dr. Dominic Robinson,

White light reflectance spectroscopy and fluorescence spectroscopy can be used to quantify concentrations of absorbing (e.g. blood, bilirubin, melanin) and fluorescent (e.g. collagen, photosensitizers) compounds in living tissues. We are investigating the use of quantitative spectroscopy for monitoring PDT in superficial skin (pre-) malignancies so that treatments can be optimized. In addition, reflectance spectroscopy is sensitive to the scattering properties of tissue, which are related to tissue architecture and nano-scale mass-density fluctuations within cells. We are currently investigating methods to quantify the optical scattering properties of turbid media such as tissue, and aim to relate these scattering properties to cellular ultrastructure and tissue architecture in pre-clinical models and to use these scattering properties as optical biomarkers of e.g. pre-malignant disease states.

Subtheme 2: Inflammation
A. Psoriasis and comorbidities

Drs. Emmilia Dowlatshahi, drs. Ella van der Voort, dr. Marlies Wakkee, dr. Tamar Nijsten

Psoriasis is a chronic inflammatory skin disease that may be associated with psoriatic arthritis (~10% of patients). In the last decade, multiple studies have demonstrated that psoriasis patients are at an increased risk of developing metabolic syndrome, cardiovascular disease (including acute myocardial infarction and stroke) and several other systemic diseases. It has been hypothesized that this link is due to increased levels of inflammatory cytokines in the circulation in psoriasis patients compared to control populations and/or to a genetic predisposition of psoriasis patients to develop other metabolic and cardiovascular diseases. However, most of these observational studies have been conducted in routine medical databases (pharmacy dispensing data, primary physician databases and claims data) and suffered from several important classical biases such as surveillance bias and residual confounding. None of the studies have investigated the genetic predisposition.

Aims:

• To study the association between psoriasis and cardiovascular disease.
• To study the genetic predisposition of psoriasis patients to obesity, diabetes and cardiovascular events.
• To study the association between liver diseases and psoriasis.

Methods: About 350 participants of the Rotterdam Study suffer from psoriasis (confirmed by their medical records and history of drug prescriptions). Because cohort members have all been very well described and have been screened for all the components of metabolic syndrome and cardiovascular disease, it is an ideal study population to compare the incidence of cardiovascular disease between controls to psoriasis patients after adjusting for the pivotal confounders. Moreover, it allows us to see whether psoriasis patients share genetic risk factors with obese and diabetic patients who are at an increased risk of developing cardiovascular diseases.

B. Clinical trials in immune mediated inflammatory skin diseases including psoriasis, hidradenitis suppurativa, atopic eczema and chronic urticaria

Dr. Bing Thio, Prof. dr. Errol Prens, dr. Martijn van Doorn,

Psoriasis, hidradenitis suppurativa, atopic eczema and chronic urticaria are are skin diseases that are part of the ‘immune mediated inflammatory diseases’ (IMIDs) These IMIDs affect a large percentageof the population and have a large impact on people’s quality of life and often require life-long therapy. Many patients require a form of systemic therapy. In addition to conventional systemic drugs, in the last decade, the highly specific biologic drugs have been introduced in the treatment of these IMIDs in dermatology and new drugs are being developed.

Aims:

• To evaluate new (pharmacological) treatments (including biologics) in fase II (cooperation with Centre for Human Drug Research in Leiden) and fase III/IV clinical studies for dermatological IMIDs
• To evaluate the effect of fumaric acid in the treatment of psoriasis.
• To evaluate daily practice effectiveness of systemic treatments
• To evaluate the added value of therapeutic drug monitoring of biologics in IMIDs (collaboration with the department of pharmacy, clinical pharmacology and immunology)

Methods: We participate in many fase II (Centre for Human Drug Research) and international fase III RCTs evaluating new drugs coming to the market. Also, we have several investigator initiated clinical studies that, focus on the effectiveness of fumaric acids and combination therapies such as fumaric acid with etanercept and methotrexate combined with adalimumab. Therapeutic drug monitoring (measuring through levels and anti-drug antibodies) of therapy with biologics is done in close collaboration with the department of pharmacy and immunology. We are also setting up a patient registry of IMID patients that are treated with systemic therapy (including biologics) to evaluate daily clinical practice data and long term safety. This registry is being set up in collaboration with the Radboud mc and AMC (psoriasis), UMCU (chronic urticaria and eczema) and UMCG (hidradenitis).MSc. students with an interest in inflammatory dermatoses are encouraged to make further inquiries and are very welcome to join any of the existing or new projects that are taking place in the Erasmus MC or in the Centre for Human Drug Research in Leiden.

In our department several dermatological diseases are being treated with Lasers. Laserlight selectively targets water and chromophores such as hemoglobin or melanin in the skin. By absorption of high energy laserlight, skin structures containing these chromophores can be targeted selectively. Skin conditions such as hemangiomas, naevus flammeus, facial or leg teleangiectasias, pigmented lesions, hairs and tattoos can be treated succesfully. Generally many treatment sessions are required to obtain optimal results. The mode of action and the efficacy of lasers and side-effects of laser treatments can be improved. Laser treatment can also be combined with certain (locally active) drugs.

Aims: To investigate optimisation strategies for laser treatment efficacy.

Methods: The efficacy of lasers may be improved in several ways. Laser treatments can be enhanced by combined treatment with certain drugs. For example, the neovascularization after laser treatment of naevus flammeus can be blocked by using angiogenesis inhibiting drugs such as sirolimus. Treatment of lentigo maligna (a potential precursor of melanoma) can more effectively be treated when laser evaporation is combined with a topical immune response enhancing drug such as imiquimod. Alos, the recurrence rate of laser-treated warts can be mimimized by post-laser evaporation addition of topical bleomycin. All these projects are being executed in investigator-initiated trials. MSc. students with an interest in laser therapy are encouraged to make further inquiries and are very welcome to join any of the existing or new projects that are taking place at the department of laser dermatology and Erasmus Aesthetics.

Subtheme 3: Phlebology
A. Clinical studies in treatment of varicose veins

Dr. Renate van den Bos, drs. Anke Biemans, Prof. dr. De Maeseneer, Prof. dr. Martino Neumann, Prof. dr. Tamar Nijsten

In the last century, the golden standard in the treatment of varicose veins has been surgical ligation and stripping. In the last decade, new minimal invasieve techniques have been introduced that use heat generated by laser light, radiofrequency or steam to ablate the varicose vein. These new techniques are highly effective, have few side effects and are very well tolerated by patients. However, not all of these techniques have been standardized to provide optimal care and the number of comparative and cost effectiveness studies is limited.

Aims:

• standardize laser parameters to optimize patient care
• evaluate minimally invasive treatment approaches in varicose veins.
• compare the different new therapies including patient reported outcomes and costs.

Methods: There are several investigator initiated comparative clinical trials running that compare endoveneous laser therapy to steam ablation, or laser therapy to radiofrequency ablation or laser therapy to surgical stripping. Some of these trials have finished and are in the analytic stages whereas others are in the recruiting phase. The goal is to include every varicose vein patient who is treated at our department in a clinical trial that is in line with patients’ wishes. We have a special focus on patient reported outcomes such as pain experience, health related quality of life and treatment satisfaction in the treatment of varicose veins.

Prof. Guy Brusselle, Prof. Bruno Stricker, prof. dr. Joachim Aerts, . Lies Lahousse

In the Rotterdam Study, clinical epidemiologic studies of the major respiratory diseases in the elderly are performed. The main focus of the respiratory epidemiologic research are obstructive airway diseases encompassing Chronic Obstructive Pulmonary Disease (COPD) and asthma, but also lung cancer is a priority topic for investigation. In COPD, we study the natural history of the disease, the determinants of exacerbations, the association with cardiovascular and cerebrovascular diseases (comorbidities / multimorbidities) as well as the genetic susceptibility in smokers and nonsmokers to develop COPD. In addition, we aim to elucidate the genetic and clinical determinants of lung function measurements in the adult population (both spirometric measures and lung diffusing capacity).

Prof. dr. Myriam G Hunink

For many diseases there is no magic bullet to cure, care and prevention. Health and well-being require a multidimensional approach: apart from pills and medical procedures, the patient needs to pay attention to diet, exercise, healthy habits, and relaxation. Patients actively participating in their health care through a healthy lifestyle have a better prognosis and a better quality of life. There is an increasing interest among patients and healthy individuals to harness the effects of their own self-healing potential as demonstrated by the growing interest in healthy lifestyle interventions and prevention in general. In this theme we perform randomized controlled trials (RCTs), systematic reviews of RCTs, and simulation modelling to evaluate the effectiveness and cost-effectiveness of non-pharmacological lifestyle interventions for the treatment of chronic disorders.

The following are focus areas:

1) Lifestyle interventions for the prevention of cardiovascular disease and metabolic syndrome.

Traditional lifestyle interventions for the primary and secondary prevention of cardiovascular disease and metabolic syndrome focus on smoking cessation, healthy nutrition, and physical activity. In this line of research, we evaluate the relative effects of both these well-accepted interventions and also other interventions such as yoga, mindfulness, music, and martial arts.

2) Interventions to reduce chronic stress and prevent burnout among health care professionals and trainees

The epidemic of chronic stress and burnout among healthcare professionals and trainees is becoming a threat to the quality of care, patient safety, and the sustainability of healthcare organizations. Chronic stress and burnout are due to an imbalance between stressors and resources. Stressors may be job demands, ambition, perfectionism, self-criticism, lack of self-care, 24/7 electronic connectivity, and interpersonal conflicts. Resources foster resiliency and well-being and include a healthy lifestyle, social support and connection, effective communication, safety, shared purpose, meaningful activities, and competency. In this theme we focus on developing, evaluating, and implementing effective individual-directed resiliency training interventions including support groups, mindfulness, yoga, exercise, martial arts, music and life-balance activities.

Subtheme 1: Endocrinology, with a focus on thyroidology

The relation between thyroid (dys)function and clinical outcomes of aging

Dr. L. Chaker, Prof. dr. R.P. Peeters

Thyroid hormone is crucial for normal function of practically all organ systems. Overt thyroid dysfunction is related to various clinical outcomes such as cardiovascular disease, osteoporosis, and cognitive decline. Recent studies have shown that even thyroid function within the normal range may also be related to these clinical outcomes.

This research program focuses on the consequences of variations in thyroid function within the context of the Rotterdam Study, a prospective population-based study of age-related disorders that includes 15,000 persons since 1990. In a large number of subjects we can study different thyroid function parameters (TSH, FT4, TPO antibodies) in relation to detailed follow-up data on cardiovascular and metabolic disease, osteoporosis and fracture risk, cognitive decline and dementia, as well as other parameters of aging. Furthermore, we will have a new and cutting-edge method for assessing thyroid hormone metabolites, which will open new revenues for investigating the role of thyroid hormone metabolism in non-communicable diseases.

We study these endpoints in close collaboration with other research groups within the Rotterdam Study but also work together with the Erasmus MC thyroid lab, the Thyroid Study Collaboration and other cohorts within the Charge Consortium. This work has resulted in several important findings and results (Chaker et al, Circulation, 2016, Bano et al. JAMA Intern. Med. 2017, Teumer, Chaker et al, Nat Commun, 2018) concerning the physiology, genetic background and consequences of thyroid function.

Specific subtopics within the research line:

• Thyroid function and cardiovascular complications
  • Myocardial infarction, cardiovascular mortality, heart failure
  • Cardiac function (imaging and non-imaging)
  • Determinants in variations in outcomes (subgroup analyses)
• Thyroid function and bone parameters
  • Osteoporosis and fracture risk
  • Bone geometry and other bone imaging modalities
  • Osteoarthritis
• Thyroid function and neuro-epidemiology and pychiatry
  • Cognitive decline, Alzheimer’s disease and dementia
  • Depression and depressive disorders
  • Cerebrovascular disorders
  • Pre-clinical markers of degenerative disease (functional imaging and biomarkers)
• Determinants and course of thyroid function during aging:
  • Longitudinal changes in thyroid function
  • Risk factors for changes in thyroid function
  • Assessing the frequency and influence of thyroid medication use

Thyroid function and adverse pregnancy outcomes or suboptimal child development

Dr. T.I.M. Korevaar, Prof. dr. R.P. Peeters,

Thyroid hormone plays an important role in the development of early pregnancy as well as fetal growth and development. Over the last two decades it has been shown that even slight alterations in thyroid function may impact on the course of pregnancy and the development of the child. The thyroid group of the Academic Center for Thyroid diseases has contributed to this literature using data from multiple prospective cohorts including Generation R, the SELMA study and we have also founded the Consortium on Thyroid and Pregnancy (https://www.consortiumthyroidpregnancy.org). For example, we have shown that both low and high thyroid function is associated with suboptimal child brain development (Korevaar et al. Lancet D&E 2017, Janssen et al. Lancet D&E 2019), we have identified that thyroid function and/or thyroid antibodies are a risk factor for preterm birth and abnormal birth weight (Korevaar et al. JAMA 2019, Derakhshan et al. Lancet D&E) and we have done work focusing on the differences in the physiology of thyroid function during pregnancy. The latter includes a wide range of potential environmental, genetic and inter,- or intra-individual determinants. We work in close collaboration with various other research groups but also with the Erasmus MC thyroid laboratory. This allows us to form novel research hypotheses based on basic scientific evidence and translate this to novel clinical research projects.

MSc students will be able to have their own, first-author research project of their choice using either the data of Generation R, the data that we have available from other cohorts, or the data collected in the Consortium on Thyroid and Pregnancy, focusing for example on:

• Determinants of thyroid function during pregnancy, such as endocrine disrupting chemicals, genetic factors or other pregnancy hormones (for example hCG)
• Thyroid function and adverse pregnancy outcomes
• Development of bone, cardiovascular or neurocognitive parameters in the child
• Thyroid dysfunction during pregnancy and postpartum maternal health

Subtheme 2: Nephrology

Dr. L. Chaker, Prof. dr. E.J. Hoorn

The kidneys have several important functions, including removing waste products from the human body and regulating fluid balance and electrolyte levels, making them essential for healthy functioning of the human body. A reduced kidney function or chronic kidney disease is a major global health burden and has been previously associated with increased cardiovascular and cerebrovascular mortality, increased mortality and reduced quality of life. Early and precise identification of patients at risk for kidney damage could be beneficial since preventive treatment can slow down kidney damage and reduce cardiovascular morbidity and mortality.

The Rotterdam Study is a large prospective population-based cohort study, including approximately 15,000 middle aged and elderly participants. This cohort study was designed to investigate the determinants and occurrence of cardiovascular, neurological, ophthalmologic, psychiatric, and endocrine diseases. Within the participants of the Rotterdam Study, several assessments of kidney function are available, including different assessments of the estimated glomerular filtration rate and the urine albumin-to-creatinine ratio. Therefore, we are able to link several assessments of kidney function to many available outcomes, including cardiovascular and neurological outcomes. Furthermore data on electrolytes and echocardiographic data on kidney size and structure is also available and several urinary biomarkers are being collected, the association of this data between kidney and cardiovascular outcomes can also be explored.

Prostaglandin E2 (PGE2) is one of these potential biomarkers and plays an important role in kidney physiology and cardiovascular function. The effects of PGE2 are mainly known from the renal effects of non-steroidal anti-inflammatory drugs, that inhibit PGE2 production. Little is known of the relation between urinary PGE2 excretion and kidney damage or cardiovascular health.

Examples of potential projects within the research line:

• Determinants of several assessments of kidney function (e.g. cystatin C)
• Investigating the association of kidney function with:
  • Cardiovascular outcomes, including atrial fibrillation, diabetes mellitus, and atherosclerosis.
  • Neurological outcomes, including stroke, dementia and cognitive function, and Parkinson’s disease.
  • Pulmonary outcomes, including lung function, asthma, and COPD
  • Bone parameters, including osteoporosis, bone density, and bone structure
• Investigating the association of electrolytes with several cardiovascular and neurological outcomes, as well as with bone and endocrine parameters
• Urinary prostaglandin E2
  • Determinants of urinary PGE2
  • The association between urinary PGE2 and several assessments of kidney function
  • PGE2 and cardiovascular outcomes
• Finding predictors for subjects at risk for kidney function decline
  • Using baseline characteristics of included patients
  • Using known markers of kidney function decline such as albuminuria
  • Using urinary parameters including novel biomarkers

Subtheme 3: Clinical immunology

Dr. L. Chaker, Dr. V.A.S.H. Dalm, Prof. dr. P.M. van Hagen, Prof. dr. R.P. Peeters

Within the Rotterdam Study, we have measured serum immunoglobulins (IgA, IgG, and IgM) in nearly 9,000 participants. This provides the unique opportunity to perform a wide range of studies on the association of serum immunoglobulins in middle-aged and elderly individuals from the general population. Serum immunoglobulins play important roles in the immune response against pathogens, but help clear aberrant cells as well. On the other hand, immunoglobulins may be involved in various autoimmune and inflammatory disorders. Currently, little is known about the role of immunoglobulins in population-based settings.

We have recently published a study on factors that influence serum immunoglobulin levels in our cohort of healthy elderly. Also, we are carrying out multiple studies to assess the associations between serum immunoglobulins and various health related outcomes. We have collaborations with many subgroups of the Epidemiology department (e.g. respiratory medicine, cardio-metabolic epidemiology, neuro-epidemiology) and other departments within the Erasmus MC as well.

Master students will be able to perform independent research with prospects of a peer-reviewed publication on one of the following topics:

• Immunoglobulins and depression/depressive disorders and other neuropsychiatric diseases
• Immunoglobulins and risk of cancer and neoplasms
• Multi-omics analyses including genome-wide association study on immunoglobulins

Dr. ir. Trudy Voortman, dr. Jessica Kiefte-de Jong, dr. Kim Braun, dr. Chantal Koolhaas

Projects in this theme are embedded in the Nutrition and Lifestyle group of the department of Epidemiology. Within this group, we aim to evaluate lifestyle factors; including nutrition, physical activity, and body composition, in relation to health across the life course. In close collaboration with other departments, research areas focus on nutrition, physical (in)activity and body composition in relation to cardiovascular health, DNA methylation, inflammation, gut microbiome composition, metabolic health, and several other aspects of health by using data from two prospective cohort studies: The Generation R Study and The Rotterdam Study.

The Generation R Study is a birth cohort of children and their parents who are followed from pregnancy onward. The children are currently 10 to 12 years of age.

The Rotterdam Study is a prospective cohort study of middle-aged and elderly, focusing on determinants of common age-related diseases such as cardiovascular disease, dementia, diabetes, and cancer.

Additionally, by performing systematic reviews and meta-analyses, we create additional knowledge beyond the information present in these cohort studies.

Specific topics within this research line are briefly outlined below:

Nutrition

Nutrition can be measured as dietary intake or nutritional biomarkers. Dietary intake can be measured by use of questionnaires and categorized in intake of individual nutrients, intake of specific foods or food groups, or overall dietary patterns. Nutritional biomarkers can be measured in tissues, such as blood. In The Generation R Study, information on dietary intake is measured through food frequency questionnaires during pregnancy, infancy, and childhood. Information on nutritional biomarkers, including levels of folate, vitamin B12 and vitamin D, is measured in blood during pregnancy, infancy and childhood. In The Rotterdam Study information on dietary intake is collected through food frequency questionnaires at baseline and repeated during follow-up. Nutritional biomarkers, such as levels of folate and vitamin B12, are measured in blood.

Activity (24-hour activity)

The 24-hour cycle of activity includes physical activity, sedentary behavior, and sleep. Whereas sleep is more a psychological factor it can be included in the 24-hour cycle of activity to examine the association between specific patterns of activity and health. For all activity measures, The Rotterdam Study collected information through questionnaires and through accelerometer.

An accelerometer is a device that measures acceleration and that can be used to identify intensity of activity. In The Generation R Study, information on activity is measured through accelerometer in a subset of participants aged 9-12 years.

Physical activity

Physical activity can be measured through questionnaire, or through an objective device called an accelerometer. Most research so far has focused on questionnaire-assessed physical activity, and the association between physical activity measured through accelerometer and health outcomes remains unclear for several domains. For example:

• Is light intensity physical activity – in contrast to moderate-to-vigorous activity – associated with health?
• To what extent are physical activity data assessed by questionnaire and accelerometer correlated?
• Will physical activity measured by questionnaire and accelerometer be associated with similar risk of disease (e.g. CVD/cancer/mortality)?

Sedentary behavior

The official definition of sedentary behavior is any waking behavior characterized by an energy expenditure ≤1.5 metabolic equivalents (METs), while in a sitting, reclining or lying posture. In simple words, sedentary behavior can also be described with the term ‘sitting’. Most research up to date has focused on sedentary behavior assessed by questionnaire, which includes specific contexts of sitting (e.g. watching television or working behind a computer). It remains unclear whether sedentary behavior in every context is associated with worse health.

Additionally, it remains unclear if uninterrupted bouts of sedentary behavior are associated with worse health outcomes compared to interrupted bouts. Questions related to this area are for example: to what extent are sedentary behavior asses by questionnaire and accelerometer correlated; and which factors are associated with the (dis)agreement?

Compositional analysis

The composition of daily activity is restricted to 24 hours. Therefore, by definition, once a person engages in more physical activity, this person will engage in less sedentary behavior and/or sleep. Up to now, this dependency has not often been accounted for in research. By measuring activity during 24-hours with an accelerometer, The Rotterdam Study has the perfect data to analyze activity in a compositional approach. Research questions related to this topic can be for example whether physical activity, sedentary behavior, and sleep are independently associated with incidence of certain diseases.

Body composition

Obesity is an important determinant of several health outcomes. Obesity is often measured as BMI (kg/m2), but this measures is limited regarding prediction of health because it does not take into account body composition. Therefore, detailed measures of body composition may provide better risk prediction for health outcomes. In both The Generation R Study and The Rotterdam Study assessment of detailed body composition (body fat, lean mass, bone mass) was performed with the use of Dual-energy X-ray absorptiometry (DXA).