In industrialized countries like Germany, the rise of chronic diseases such as cancer, atherosclerosis, diabetes, osteoarthritis and Alzheimer’s disease represents an ever-growing challenge to the health care system. The causes of these disorders are multi-factorial and consist of environmental, life style and genetic factors, the constellation of which is unique for each individual. The National Cohort is the largest German health research initiative, to address this challenge, by designing a longterm prospective and multidisciplinary cohort among the general adult population.
Since early 2007, under initiative of the Helmholtz Association a network of German research institutions has jointly been developing the national cohort as a common, national resource for studies on the risk factors and etiologic mechanisms of major diseases in the German population. The institutions include several of the publically funded Helmholtz institutes, a large number of universities, and other non-Helmholtz public research institutions.
Within the National Cohort the Helmholtz Centre for Infection Research is in charge of those aspects of the Cohort that relate to infectious diseases and disorders of the immune system. Our approach will follow two tiers: firstly, to evaluate microorganisms as risk factors for the development of acute and chronic diseases; secondly, to identify environmental, life style and genetic host factors that represent risk factors for the development of certain infectious or immunological diseases.
The National Cohort is designed to address research questions concerning a wide range of possible causes of major chronic diseases. The overarching objective of the National Cohort is to provide a sound knowledge base for improved and more targeted measures for the primary and secondary prevention of major diseases, tailored to the German population. The National Cohort will include a total of 200,000 individuals aged 20 to 69 years (40,000 individuals younger than 40 years, and 160,000 individuals aged at least 40 years), who will be recruited through a network of 18 study centers, organized in eight geographic clusters throughout Germany, representing the population of almost all federal states and covering metropolitan, urban and rural regions. At each of the centers, a random sample of the general population will be drawn from local municipal population registries within defined strata of age and sex. An overall study participation proportion of at least 50% will be targeted. All participants will be invited to the study centers to take part in physical and medical examinations, the collection of biomaterials, a computer-assisted personal interview, and to fill in computer-aided or web-based questionnaires.
The collection of biomaterials in combination with extensive information from questionnaires and medical examinations represents one of the central components. Using combinations of such information – repeated over time – will make it possible to specifically address pathways of disease development providing clues to the biological mechanisms that may explain observed relationships. Information will be collected at two different levels of intensity:
At the basic study level (“Level 1”), applying to all 200,000 study participants, baseline interviews, questionnaires and examinations will be performed, by using a 2.5-h interview and examination protocol. Physical and medical examinations will include measurements of anthropometric indices, a dual-energy x-ray assessment (DXA) of body composition and bone density, blood pressure measurements, measurements of arterial stiffness, an electrocardiogram (ECG), three-dimensional echocardiography, spirometry, measurements of physical activity through accelerometry (7 days), a basic test of physical fitness, an assessment of cognitive function, and a tooth count.
A further key element of the core study protocol at Level 1 is the collection of biomaterials from all study participants.
At a second study level ("Level 2"), applying to a 20% representative sub-sample of the cohort (40,000 subjects) proportionally spread over all participating study centers and age-strata, an intensified and extended 4-hour examination protocol will be employed that, in addition to the general examinations of Level 1, include an oral glucose tolerance test, carotid sonography with measurement of intima-media-thickness, long-term ECG, sleep apnea assessment, enhanced motoric, sensoric and cognitive function tests, measurement of airway inflammation, assessment of oral health, and additional questionnaires.
A further intensified study level is formed by a whole-body MRI program (including whole body, cardiac, and brain MRI protocol), which will also involve 40,000 subjects in selected study centers. Whole-body MRI will generate a comprehensive morphologic and functional data base to be used to estimate the prevalence and incidence of MRI based findings and their regional distribution their changes over time. This data base will be used to identify novel morphologic MRI-based markers of risk for various disease states and subclinical morphologic and functional changes.
In addition, an add-on “Level 3” studies that require further in-depth phenotyping or disease ascertainments have been planned at some or all of the study centers.
The department of epidemiology at HZI is currently involved in conducting various feasibility studies within the Level 3 of the National Cohort with a focus on infectious diseases and immunology:
- Gastrointestinal Erreger (Serum und Stuhl)
- Cervico-vaginal self-sampling and pathogen determination
- Comparison of stool sampling at home versus at the study center
- Questionnaire to screen for selected infectious diseases in population-based epidemiological studies
- Use of web-based tools to collect data on infectious diseases in population-based epidemiological studies
- Vaccination record retrieval
The Hannover Study center has been fully operational since April 2012 and has recently completed the pretest 2 phase of the national cohort, involving the recruitment, examination and data collection of participants.
Verein Nationale Kohorte: DKFZ, HMGU, DZNE, MDC and multiple universities