The aim of the NAKO Health Study is to investigate chronic diseases such as cancer, diabetes, cardiovascular diseases, rheumatism, infections and depression in order to improve the prevention, early diagnosis and treatment of these widespread diseases.
In May, the third phase of the NAKO health study (formerly the National Cohort, or NAKO for short) began. At the Kiel Study Centre, the focus is on examining teeth and gums, because inflammation in the mouth can also affect other parts of the body. For example, periodontitis, or inflammation of the gums, is a risk factor for heart attack, stroke and diabetes mellitus. Another focus in Kiel is the molecular biological analysis of NAKO samples.
What keeps us healthy? What makes us ill?
"With this funding, the scientific value of the study increases enormously," emphasises the scientific director of the Nako Study Centre in Kiel and DZHK scientist, Professor Wolfgang Lieb from the Medical Faculty of the Christian Albrecht University in Kiel (CAU). "The purpose of this study is to follow the participants over a longer period of time and see how their state of health develops, how their living conditions change, how their health parameters change, who stays healthy in the long term and who develops diseases over time. A long follow-up period is extremely important for this," explains the Director of the Institute of Epidemiology at the University Hospital of Schleswig-Holstein (UKSH), Campus Kiel, who is also a member of the NAKO Board.
A total of 4,864 women and 4,627 men aged 20 to 79 years were examined at the Kiel Study Centre as part of the baseline study (2014-2019). By taking part, they are making an important contribution to health research and, if they wish, will receive the results of the examinations in an easily understandable form. The more of them take part in the follow-up examinations, the better.
"We are assuming that 70 per cent of the original participants, i.e. around 6,650 people, will take part in the follow-up examination," says Lieb. Currently (as of April 19), 4,383 people have responded to the call for a follow-up examination. The next step will be to analyse how the study participants have changed from the first to the second examination, both in terms of their physical and mental health.
Oral inflammation and possible consequences
In addition to the basic examinations, which are carried out in the same way in all study centres, there are additional examinations that are only carried out in certain study centres. In Kiel and nine other study centres, for example, there is an additional detailed examination of dental and oral health. Among other things, the number of teeth and implants, the caries status and inflammation of the gums as well as possible dentures will be recorded and functional findings of the jaw will be recorded. Saliva samples are also taken. These data will be used to examine how diseases of the teeth and gums are associated with systemic diseases.
Diseases of the dental apparatus are widespread in Germany. More than half of 35- to 44-year-olds and almost two-thirds of 65- to 74-year-olds are affected, according to the Fifth German Oral Health Study. "There are many indications from observational studies that tooth and gum diseases are associated with chronic inflammatory general diseases. Ongoing inflammation in the mouth can also lead to problems elsewhere in the body," explains Professor Katrin Hertrampf from the Clinic for Mouth, Jaw and Facial Surgery at the UKSH, Campus Kiel, who is in charge of the dental module.
Parodontitis as a risk factor for heart attack, stroke and diabetes mellitus
It is believed that parodontitis, or inflammation of the gums, is an independent risk factor for heart attack, stroke and diabetes mellitus. "With NAKO we want to try to clarify these connections." Additional funding from the Ministry of Education, Science and Culture of the State of Schleswig-Holstein and the Medical Faculty of the CAU will enable Hertrampf's group to carry out further studies. "We are very happy about this multi-year funding for a comprehensive dental data collection. This is a unique opportunity for the NAKO sites to collect bioprobes from dental plaque and gingival pockets for the analysis of the oral microbiome," says Hertrampf.
Which came first - the disease or the change in the microbiome?
One way of finding out is to take a molecular biological look at samples taken from the mouth. "We investigate the microorganisms present in saliva and dental plaque and the functions they perform," explains Dr. Corinna Bang from the Institute of Clinical Molecular Biology (IKMB). The main aim is to understand the disease-associated microbiome in parodontitis. It is now known that many bacteria that cause parodontitis can also lead to other diseases.
"The problem with the microbiome is that we never really know what comes first - the disease or the change in the microbiome. This can only be found out in a study like NAKO, where people are observed over a longer period of time," says the head of the microbiome laboratory at the IKMB. Dr. Corinna Bang and Professor Andre Franke, director of the IKMB and board member of the Excellence Cluster "Precision Medicine in Chronic Inflammation" (PMI), are also responsible for some of the molecularbiological analyses of the bioprobes in the NAKO. This includes, for example, determining the gut microbiome by analysing faecal samples.
Better knowledge of the genetic basis of disease and health
In the future, the Kiel site would also like to participate in NAKO's genetic analysis of blood samples. "For example, we are interested in how the gut microbiome and the oral microbiome interact with human genetics," says Bang. "The beauty of NAKO is that you can relate the molecular data to a very broad range of health parameters and diseases," says epidemiologist Lieb. "This is a very large research resource. Once we have collected the genetic data of the volunteers, we will be able to correlate them with more than 500 clinical variables, such as blood pressure, body weight and levels of uric acid. This will significantly improve our understanding of the genetic basis of disease and health.
About the NAKO health study
The NAKO Health Study is the largest population-based prospective long-term study in Germany to date. Since 2014, adults randomly selected from the population registers have been undergoing medical examinations and interviews at 18 study centres across the country. The aim is to investigate chronic diseases such as cancer, diabetes, cardiovascular diseases, rheumatism, infections and depression in order to improve the prevention, early diagnosis and treatment of these widespread diseases.
The project is funded by the German Federal Ministry of Education and Research, the participating states and the Helmholtz Association. 205,000 people have taken part in the NAKO baseline study, and the follow-up study is still ongoing.
Further information:
NAKO health study: https://nako.de/
NAKO health study Kiel: https://kiel.nako.de/
Scientific contact: Prof. Dr. Wolfgang Lieb, Institute for Epidemiology, UKSH, Campus Kiel, Medical Faculty, CAU, 0431/500-30201 (office), wolfgang.lieb(at)epi.uni-kiel.de
Source: Christian-Albrechts-Universität zu Kiel (CAU) press release