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The German National Cohort (NAKO) is a multidisciplinary, population-based prospective cohort study that aims to investigate the causes of widespread diseases, identify risk factors and improve early detection and prevention of disease. Specifically, NAKO is designed to identify novel and better characterize established risk and protection factors for the development of cardiovascular diseases, cancer, diabetes, neurodegenerative and psychiatric diseases, musculoskeletal diseases, respiratory and infectious diseases in a random sample of the general population. Between 2014 and 2019, a total of 205,415 men and women aged 19-74 years were recruited and examined in 18 study centres in Germany. The baseline assessment included a face-to-face interview, self-administered questionnaires and a wide range of biomedical examinations. Biomaterials were collected from all participants including serum, EDTA plasma, buffy coats, RNA and erythrocytes, urine, saliva, nasal swabs and stool. In 56,971 participants, an intensified examination programme was implemented. Whole-body 3T magnetic resonance imaging was performed in 30,861 participants on dedicated scanners. NAKO collects follow-up information on incident diseases through a combination of active follow-up using self-report via written questionnaires at 2-3 year intervals and passive follow-up via record linkages. All study participants are invited for re-examinations at the study centres in 4-5 year intervals. Thereby, longitudinal information on changes in risk factor profiles and in vascular, cardiac, metabolic, neurocognitive, pulmonary and sensory function is collected. NAKO is a major resource for population-based epidemiology to identify new and tailored strategies for early detection, prediction, prevention and treatment of major diseases for the next 30 years., (© 2022. The Author(s).)

Background: Numerous studies have reported an increase in mental disorders during the COVID-19 pandemic, but the exact reasons for this development are not well understood. In this study we investigate whether pandemic-related occupational and financial changes (e.g., reduced working hours, working from home, financial losses) were associated with increased symptoms of depression and anxiety compared with the situation before the pandemic., Methods: We analyzed data from the German National Cohort (NAKO) Study. Between May and November 2020, 161 849 study participants answered questions on their mental state and social circumstances. Their responses were compared with data from the baseline survey before the pandemic (2014-2019). Linear fixed-effects models were used to determine whether individual changes in the severity of symptoms of depression (PHQ-9) or anxiety (GAD-7) were associated with occupational/ financial changes (controlling for various covariates)., Results: The prevalence of moderate or severe symptoms of depression and anxiety increased by 2.4% and 1.5%, respectively, during the COVID-19 pandemic compared with the preceding years. The mean severity of the symptoms rose slightly. A pronounced increase in symptoms was observed among those who became unemployed during the pandemic (+ 1.16 points on the depression scale, 95% confidence interval [0.91; 1.41], range 0-27). Increases were also seen for reduced working hours with no short-time allowance, increased working hours, working from home, insecurity regarding employment, and financial strain. The deterioration in mental health was largely statistically explained by the occupational and financial changes investigated in the model., Conclusion: Depressive symptoms and anxiety disorders increased slightly in the study population during the first year of the COVID-19 pandemic. Occupational and financial difficulties were an essential contributory factor. These strains should be taken into account both in the care of individual patients and in the planning of targeted prevention measures.

Background: Infectious diseases continue to play an important role for disease perception, health-economic considerations and public health in Germany. In recent years, infectious diseases have been linked to the development of non-communicable diseases. Analyses of the German National Cohort (GNC) may provide deeper insights into this issue and pave the way for new targeted approaches in disease prevention., Objectives: The aim was to describe the tools used to assess infectious diseases and to present initial data on infectious disease frequencies, as well as to relate the GNC assessment tools to data collection methods in other studies in Germany., Methods: As part of the baseline examination, questions regarding infectious diseases were administered using both an interview and a self-administered touchscreen questionnaire. Data from the initial 101,787 GNC participants were analysed., Results: In the interview, 0.2% (HIV/AIDS) to 8.6% (shingles) of respondents reported ever having a medical diagnosis of shingles, postherpetic neuralgia (in cases where shingles was reported), hepatitis B/C, HIV/AIDS, tuberculosis or sepsis if treated in hospital. In the questionnaire, 12% (cystitis) to 81% (upper respiratory tract infections) of respondents reported having experienced at least one occurrence of upper or lower respiratory tract infections, gastrointestinal infections, cystitis or fever within the past 12 months., Outlook: The cross-sectional analyses of data and tools presented here - for example on determinants of susceptibility to self-reported infections - can be anticipated from the year 2021 onward. Beyond that, more extensive research into infectious disease epidemiology will follow, particularly once analyses of GNC biological materials have been performed.

Background: Caries and periodontitis are highly prevalent worldwide. Because detailed data on these oral diseases were collected within the framework of the German National Cohort (GNC), associations between oral and systemic diseases and conditions can be investigated., Objectives: The study protocol for the oral examination was designed to ensure a comprehensive collection of dental findings by trained non-dental staff within a limited examination time. At the mid-term of the GNC baseline examination, a first quality evaluation was performed to check the plausibility of results and to propose measures to improve the data quality., Materials and Methods: A dental interview, saliva sampling and oral diagnostics were conducted. As part of the level‑1 examination, the number of teeth and prostheses were recorded. As part of the level‑2 examination, detailed periodontal, cariological and functional aspects were examined. All examinations were conducted by trained non-dental personnel. Parameters were checked for plausibility and variable distributions were descriptively analysed., Results: Analyses included data of 57,967 interview participants, 56,913 level‑1 participants and 6295 level‑2 participants. Percentages of missing values for individual clinical parameters assessed in level 1 and level 2 ranged between 0.02 and 3.9%. Results showed a plausible distribution of the data; rarely, implausible values were observed, e.g. for measurements of horizontal and vertical overbite (overjet and overbite). Intra-class correlation coefficients indicated differences in individual parameters between regional clusters, study centres and across different examiners., Conclusions: The results confirm the feasibility of the study protocol by non-dental personnel and its successful integration into the GNC's overall assessment program. However, rigorous dental support of the study centres is required for quality management.

Background: Asthma is one of the most common chronic diseases in both children and adults. Asthma first occurring in adulthood (adult-onset asthma, AOA) is associated with poorer prognosis compared to childhood-onset asthma (COA), which urgently calls for more research in this area. The aim of this work was to analyze the data on asthma collected in the German National Cohort and compare it with the German Health Interview and Examination Survey for Adults (DEGS), in particular regarding AOA., Material and Methods: Our analysis was based on the dataset of the main questionnaire at mid-term of the German National Cohort baseline examination, comprising 101,723 participants. Variables considered in the analyses were self-reported diagnosis of asthma, age at first diagnosis, asthma treatment in the past 12 months, age, and sex., Results: In the midterm dataset, 8.7% of women and 7.0% of men in the German National Cohort reported that they had ever been diagnosed with asthma. Approximately one third of participants with asthma received their initial diagnosis before their 18th birthday. COA affected 2.2% of women and 2.8% of men, whereas AOA affected 6.5% of women and 4.2% of men. During the previous 12 months, 33% of COA cases and 60% of AOA cases were medically treated., Conclusion: The proportion of persons affected by asthma in the German National Cohort, as well as observed patterns regarding age and gender, corresponds to other data sources such as DEGS. However, in our analysis, the proportion of individuals with AOA was higher than described in the literature. The increase in cumulative asthma diagnoses with age is markedly steeper in younger participants, indicating a rising trend over time.

Background: Persons with a migration background (PmM) as a population group usually differ from the autochthonous population in terms of morbidity, mortality, and use of the health care system, but they participate less frequently in health studies. The PmM group is very heterogeneous, which has hardly been taken into account in studies so far., Objectives: Sociodemographic characteristics of PmM in the NAKO health study (age, sex, time since migration, education) are presented. In addition, it is examined through an example whether migration background is related to the use of cancer screening for colorectal cancer (hemoccult test)., Methods: Data of the first 101,816 persons of the NAKO were analyzed descriptively and cartographically. The migration background was assigned on the basis of the definition of the Federal Statistical Office, based on nationality, country of birth, year of entry, and country of birth of the parents., Results: Overall, the PmM proportion is 16.0%. The distribution across the 18 study centers varies considerably between 6% (Neubrandenburg) and 33% (Düsseldorf). With 153 countries of origin, most countries are represented in the NAKO. All variables show clear differences between the different regions of origin. In the hemoccult test, persons of Turkish origin (OR = 0.67) and resettlers (OR = 0.60) have a lower participation rate. PmM born in Germany do not differ in this respect from the autochthonous population (OR = 0.99)., Conclusion: PmM in the NAKO are a very heterogeneous group. However, due to the sample size, individual subgroups of migrants can be studied separately with respect to region of origin.

Background: Physical activity is a complex behavior that is difficult to measure validly and reliably in large, population-based studies. Data on physical activity are available for the initial 100,000 participants of the German National Cohort., Objectives: To describe the baseline physical activity assessment in the cohort and to present initial descriptive results., Material and Methods: Physical activity was assessed using a combination of tools, including two self-administered questionnaires, the Questionnaire on Annual Physical Activity Pattern (QUAP) and the Global Physical Activity Questionnaire (GPAQ); a computer-based 24‑h physical activity recall (cpar24); and 7‑day accelerometry (Actigraph GT3X/+; ActiGraph, Pensacola, FL, USA)., Results: The availability of data varied between assessment instruments (QUAP: n = 16,372; GPAQ: n = 90,900; cpar24: n = 23,989; accelerometry: n = 35,218). Analyses across measurement tools showed that on average, women spent 75 to 216 min/d, and men spent 73 to 224 min/d in moderate or higher intensity total physical activity. Persons aged 20-39 years spent 66 to 200 min/d, and persons aged 40-69 years spent 78 to 244 min/d in moderate or higher intensity total physical activity., Conclusions: Initial baseline analyses of physical activity in this cohort show the value of using a combination of questionnaires, 24‑h recalls, and a movement sensor. The comprehensive data collection represents a valuable resource for future analyses and will improve our understanding of the association between physical activity and disease prevention.

Background: Noise annoyance is associated with adverse health-related conditions and reduced wellbeing. Thereby, subjective noise annoyance depends on the objective noise exposure and is modified by personal and regional factors., Objective: How many participants of the German National Cohort Study (GNC; NAKO Gesundheitsstudie) were annoyed by transportation noise during nighttime and what factors were associated with noise annoyance?, Materials and Methods: This cross-sectional analysis included 86,080 participants from 18 study centers, examined from 2014 to 2017. We used multinomial logistic regression to investigate associations of personal and regional factors to noise annoyance (slightly/moderately or strongly/extremely annoyed vs. not annoyed) mutually adjusting for all factors in the model., Results: Two thirds of participants were not annoyed by transportation noise during nighttime and one in ten reported strong/extreme annoyance with highest percentages for the study centers Berlin-Mitte and Leipzig. The strongest associations were seen for factors related to the individual housing situation like the bedroom being positioned towards a major road (OR of being slightly/moderately annoyed: 4.26 [95% CI: 4.01;4.52]; OR of being strongly/extremely annoyed: 13.36 [95% CI: 12.47;14.32]) compared to a garden/inner courtyard. Participants aged 40-60 years and those in low- and medium-income groups reported greater noise annoyance compared to younger or older ones and those in the high-income group., Conclusion: In this study from Germany, transportation noise annoyance during nighttime varied by personal and regional factors.

High levels of adiposity in the population have a major impact on various diseases, but previous epidemiologic studies have largely been restricted to simple anthropometric measures such as the body mass index (BMI), an imperfect predictor of disease risk. There is a critical need for the use of improved measures of relative weight and body composition in large-scale, population-based research.The current article presents initial descriptive results of body composition and fat distribution based on the midterm baseline dataset of the German National Cohort, which included 101,817 participants who were examined in 18 study centers in Germany between March 2014 and March 2017. The anthropometric measures encompassed body weight, height, waist and hip circumference, bioelectrical impedance analysis (BIA), sonography of abdominal adipose tissue, 3D-body scanning, and magnetic resonance imaging.BMI analyses showed that 46.2% of men and 29.7% of women were overweight and 23.5% of men and 21.2% of women were obese. On average, women in almost all age groups demonstrated more subcutaneous adipose tissue layer thickness than men. The mean values of visceral adipose tissue layer thickness, on the other hand, were higher among men than among women in all age groups and increased continuously across age groups in both sexes.The comprehensive assessment of body composition and fat distribution provides novel future opportunities for detailed epidemiologic analyses of overweight and adiposity in relation to the development of chronic diseases.

Background: In epidemiologic studies, standardised measurement of socio-demographic and employment-related factors is becoming increasingly important, as variables such as gender, age, education or employment status are factors influencing health and disease risks., Aims: The article gives an overview of the scientific background and assessment of socio-demographic factors in the German National Cohort Study. In addition, the distribution of individual characteristics in the cohort as well as relationships with health-related measures are presented by way of example., Material and Methods: The analysis is based on the data of the first half of the baseline survey (n = 101,724). On this basis, we present the distribution of key socio-demographic characteristics and analyse relationships with exemplary selected health indicators (body mass index, self-reported health) to assess the validity of socio-demographic data measurements., Results: On average, study participants were 52.0 years old (SD = 12.4). Of the participants, 53.6% were women, 54.3% had high education, 60.1% were married and 72% were employed while 3.4% were unemployed. Well-established correlations between socio-demographic factors and health could be reproduced with the German National Cohort data. For example, low education, old age and unemployment were associated with an increased prevalence of obesity and poor self-reported health., Discussion: The German National Cohort provides a comprehensive measurement of socio-demographic characteristics. Combined with a wide range of health data and the longitudinal measurements available in the future, this opens up new opportunities for health science and social epidemiological research in Germany.

Physical fitness is defined as an individual's ability to be physically active. The main components are cardiorespiratory fitness (CRF), muscle strength, and flexibility. Regardless of physical activity level, physical fitness is an important determinant of morbidity and mortality.The aim of the current study was to describe the physical fitness assessment methodology in the German National Cohort (NAKO) and to present initial descriptive results in a subsample of the cohort.In the NAKO, hand grip strength (GS) and CRF as physical fitness components were assessed at baseline using a hand dynamometer and a submaximal bicycle ergometer test, respectively. Maximum oxygen uptake (VO 2max ) was estimated as a result of the bicycle ergometer test. The results of a total of 99,068 GS measurements and 3094 CRF measurements are based on a data set at halftime of the NAKO baseline survey (age 20-73 years, 47% men).Males showed higher values of physical fitness compared to women (males: GS = 47.8 kg, VO 2max  = 36.4 ml·min -1  · kg -1 ; females: GS = 29.9 kg, VO 2max  = 32.3 ml · min -1  · kg -1 ). GS declined from the age of 50 onwards, whereas VO 2max levels decreased continuously between the age groups of 20-29 and ≥60 years. GS and VO 2max showed a linear positive association after adjustment for body weight (males β = 0.21; females β = 0.35).These results indicate that the physical fitness measured in the NAKO are comparable to other population-based studies. Future analyses in this study will focus on examining the independent relations of GS and CRF with risk of morbidity and mortality.

Background: The German National Cohort (NAKO) is an interdisciplinary health study aimed at elucidating causes for common chronic diseases and detecting their preclinical stages. This article provides an overview of design, methods, participation in the examinations, and their quality assurance based on the midterm baseline dataset (MBD) of the recruitment., Methods: More than 200,000 women and men aged 20-69 years derived from random samples of the German general population were recruited in 18 study centers (2014-2019). The data collection comprised physical examinations, standardized interviews and questionnaires, and the collection of biomedical samples for all participants (level 1). At least 20% of all participants received additional in-depth examinations (level 2), and 30,000 received whole-body magnet resonance imaging (MRI). Additional information will be collected through secondary data sources such as medical registries, health insurances, and pension funds. This overview is based on the MBD, which included 101,839 participants, of whom 11,371 received an MRI., Results: The mean response proportion was 18%. The participation in the examinations was high with most of the modules performed by over 95%. Among MRI participants, 96% completed all 12 MRI sequences. More than 90% of the participants agreed to the use of complementary secondary and registry data., Discussion: Individuals selected for the NAKO were willing to participate in all examinations despite the time-consuming program. The NAKO provides a central resource for population-based epidemiologic research and will contribute to developing innovative strategies for prevention, screening and prediction of chronic diseases.

Background: A nationwide assessment of the respiratory status on the basis of standardized lung function measurements has so far not been available in Germany. The present work describes the lung function tests in the German National Cohort (GNC) and presents initial results based on the GNC Midterm Baseline Dataset., Material and Methods: The assessment of lung function in the GNC comprised spirometry (level 1) and the determination of exhaled nitric oxide (FeNO, level 2). Our quality assurance concept included regular training of lung function test procedures at various GNC sites, interim evaluations of test quality, as well as regular calibration/measurement checks of test equipment. For spirometry, we established a stepwise procedure for offline quality control based on raw flow volume curves., Results: In the present dataset (n = 101,734), spirometry was available for 86,893 study participants and FeNO was available for 15,228 participants. The average (±SD) FEV 1 Z score (according to GLI 2012) was -0.321 ± 1.047, the FVC Z score was -0.153 ± 0.941, and the FEV 1 /FVC Z score was -0.337 ± 0.901. The difference in FEV 1 /FVC between current smokers and never-smokers increased with age. The average FeNO was 14.2 ÷ 2.0 ppb. Current smoking reduced FeNO levels by 43%, whereas respiratory allergy increased FeNO levels by 16% in nonsmokers., Discussion: The results of spirometry and the FeNO measurements are in the expected range with regard to their distributions and correlates. The GNC provides a valuable basis for future investigations of respiratory health and its determinants as well as research into the prevention of respiratory diseases in Germany.