Kathrin Günther

Metabolic syndrome in young children: definitions and results of the IDEFICS study

Objective:To estimate the prevalence of the metabolic syndrome (MetS) using reference standards obtained in European children and to develop a quantitative MetS score and describe its distribution in children.Design and methods:Population-based survey in eight European countries, including 18745 children 2.0 to 10.9 years, recruited during a second survey. Anthropometry (weight, height and waist circumference), blood pressure and serum-fasting triglycerides, HDL cholesterol, glucose and insulin were measured. We applied three widely accepted definitions of the pediatric MetS and we suggest a new definition, to guide pediatricians in decisions about close monitoring or even intervention (values of at least three of the MetS components exceeding the 90th or 95th percentile, respectively). We used a z-score standardisation to calculate a continuous score combining the MetS components.Results:Among the various definitions of MetS, the highest prevalence (5.5%) was obtained with our new definition requiring close observation (monitoring level). Our more conservative definition, requiring pediatric intervention gives a prevalence of 1.8%. In general, prevalences were higher in girls than in boys. The prevalence of metabolic syndrome is highest among obese children. All definitions classify a small percentage of thin or normal weight children as being affected. The metabolic syndrome score shows a positive trend with age, particularly regarding the upper percentiles of the score.Conclusions:According to different definitions of pediatric MetS, a non-negligible proportion of mostly prepubertal children are classified as affected. We propose a new definition of MetS that should improve clinical guidance. The continuous score developed may also serve as a useful tool in pediatric obesity research. It has to be noted, however, that the proposed cutoffs are based on a statistical definition that does not yet allow to quantify the risk of subsequent disease.

Intercorrelations between serum, salivary, and hair cortisol and child-reported estimates of stress in elementary school girls

To evaluate the impact of stress on childrens well-being, it is important to have valid and reliable stress assessment methods. Nevertheless, selection of an appropriate method for a particular research question may not be straightforward, as there is currently no consensus on a reference method to measure stress in children. This article examined to what extent childhood stress can be estimated accurately by stressor questionnaires (i.e., Coddington life events scale) and biological markers (serum, salivary, and hair cortisol) using the Triads (a triangulation) method in 272 elementary school girls. Salivary cortisol was shown to most accurately indicate true childhood stress for short periods in the past (i.e., last 3 months), whereas hair cortisol may be preferred above salivary measurements for periods more distant and thus for chronic stress assessment. However, applicability should be confirmed in larger and more heterogeneous populations.

Influence of sample collection and preanalytical sample processing on the analyses of biological markers in the European multicentre study IDEFICS

Objective:To evaluate the influence of a standardised sampling protocol and process quality across the different IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) centres on the results of the biochemical measurements.Design:Baseline survey within the community-based intervention study.Subjects:A total of 16 224 children, aged 2–8 years, enrolled in the IDEFICS baseline survey in 8 European countries. Venous or capillary blood samples were collected from 12 430 children, urine samples from 13 890 children and saliva samples from 14 019 children.Methods:A set of quality indicators was recorded for the biological blood, urine and saliva samples collected during the IDEFICS study. Results of blood and urine measurements were analysed and stratified by selected quality indicators.Results:Concentrations of biological markers in blood and urine measured during the IDEFICS baseline survey are associated with several quality indicators assessed in this study. Between-country variations of these biomarkers are described. It was confirmed that fasting has a big influence on the concentration of certain biomarkers. Biomarkers in morning urine samples may be erroneous if the study subjects void during the night or if samples are not taken from the very first morning urine.Conclusions:The analysed data underline that a standardised sampling protocol is of major importance, especially in multicentre studies, but non-compliance is ever present in spite of well-defined standard operation procedures. Deviations from the protocol should therefore always be documented to avoid error pertaining to the concentration of biological markers.

Percentiles of fasting serum insulin, glucose, HbA1c and HOMA-IR in pre-pubertal normal weight European children from the IDEFICS cohort

Objectives:The aim of this study is to present age- and sex-specific reference values of insulin, glucose, glycosylated haemoglobin (HbA1c) and the homeostasis model assessment to quantify insulin resistance (HOMA-IR) for pre-pubertal children.Methods:The reference population consists of 7074 normal weight 3- to 10.9-year-old pre-pubertal children from eight European countries who participated in at least one wave of the IDEFICS (‘identification and prevention of dietary- and lifestyle-induced health effects in children and infants’) surveys (2007–2010) and for whom standardised laboratory measurements were obtained. Percentile curves of insulin (measured by an electrochemiluminescence immunoassay), glucose, HbA1c and HOMA-IR were calculated as a function of age stratified by sex using the general additive model for location scale and shape (GAMLSS) method.Results:Levels of insulin, fasting glucose and HOMA-IR continuously show an increasing trend with age, whereas HbA1c shows an upward trend only beyond the age of 8 years. Insulin and HOMA-IR values are higher in girls of all age groups, whereas glucose values are slightly higher in boys. Median serum levels of insulin range from 17.4 and 13.2 pmol l−1 in 3–<3.5-year-old girls and boys, respectively, to 53.5 and 43.0 pmol l−1 in 10.5–<11-year-old girls and boys. Median values of glucose are 4.3 and 4.5 mmol l−1 in the youngest age group and 49.3 and 50.6 mmol l−1 in the oldest girls and boys. For HOMA-IR, median values range from 0.5 and 0.4 in 3–<3.5-year-old girls and boys to 1.7 and 1.4 in 10.5–<11-year-old girls and boys, respectively.Conclusions:Our study provides the first standardised reference values for an international European children’s population and provides the, up to now, largest data set of healthy pre-pubertal children to model reference percentiles for markers of insulin resistance. Our cohort shows higher values of Hb1Ac as compared with a single Swedish study while our percentiles for the other glucose metabolic markers are in good accordance with previous studies.

Smoking ban in public areas is associated with a reduced incidence of hospital admissions due to ST-elevation myocardial infarctions in non-smokers. Results from the BREMEN STEMI REGISTRY:

Introduction Laws banning tobacco smoking from public areas have been passed in several countries, including the region of Bremen, Germany at the end of 2007. The present study analyses the incidence of hospital admissions due to ST-elevation myocardial infarctions (STEMIs) before and after such a smoking ban was implemented, focusing on differences between smokers and non-smokers. In this respect, data of the Bremen STEMI Registry (BSR) give a complete epidemiological overview of a region in northwest Germany with approximately 800,000 inhabitants since all STEMIs are admitted to one central heart centre. Methods and results Between January 2006 and December 2010, data from the BSR was analysed focusing on date of admission, age, gender, and prior nicotine consumption. A total of 3545 patients with STEMI were admitted in the Bremen Heart Centre during this time period. Comparing 2006–2007 vs. 2008–2010, hence before and after the smoking ban, a 16% decrease of the number of STEMIs was observed: from a mean of 65 STEMI/month in 2006–2007 to 55/month in 2008–2010 (p < 0.01). The group of smokers showed a constant number of STEMIs: 25/month in 2006–2007 to 26/month in 2008–2010 (+4%, p = 0.8). However, in non-smokers, a significant reduction of STEMIs over time was found: 39/month in 2006–2007 to 29/month in 2008–2010 (−26%, p < 0.01). The decline of STEMIs in non-smokers was consistently observed in all age groups and both sexes. Adjusting for potentially confounding factors like hypertension, obesity, and diabetes mellitus did not explain the observed decline. Conclusions In the BSR, a significant decline of hospital admissions due to STEMIs in non-smokers was observed after the smoking ban in public areas came into force. No reduction of STEMI-related admissions was found in smokers. These results may be explained by the protection of non-smokers from passive smoking and the absence of such an effect in smokers by the dominant effect of active smoking.

Predictors of acute kidney injury in patients admitted with ST-elevation myocardial infarction – results from the Bremen STEMI-Registry

Background: Deterioration of renal function after exposition to contrast media is a common problem in patients with myocardial infarction undergoing percutaneous coronary interventions. The aim of the present study was to assess the incidence of acute kidney injury in patients admitted with ST-elevation-myocardial infarction (STEMI) and its association with infarction severity, comorbidities and treatment modalities, including amount of contrast media applied. Methods: All patients with STEMI from the metropolitan area of Bremen, Germany are treated at the Bremen Heart Centre and since 2006 documented in the Bremen STEMI-Registry. Acute kidney injury was graded from stage 0 to 3 following the Kidney-disease-improving-global outcomes criteria from 2012. Results: Data from 3810 patients admitted with STEMI were included in this study. No acute kidney injury was observed in 3120 (82%) patients while acute kidney injury was detected in 690 (18%) patients: Stage 1: n=497 (13%), 2: n=66 (2%), 3: n=127 (3%). Acute kidney injury was associated with elevated 30-day (0: 3%, 1: 20%, 2: 46%, 3: 58%) and one-year mortality rates (0: 6%, 1: 26%, 2: 49%, 3: 66%). Higher acute kidney injury stages were associated with higher peak creatine kinase (in U/l±SEM): stage 0: 1748±33, 1: 2588±127, 2: 3684±395, 3: 3330±399, p (<0.01), lower mean systolic blood pressure at admission (in mmHG±SD): 0: 133±28, 1: 129±31; 2: 121±31, 3: 115±33 (p<0.01) and higher Thrombolysis in Myocardial Infarction risk score for STEMI (scale 0–14±SD): 0: 2.71±2, 1: 4.08±2, 2: 4.98±2, 3: 5.05±2, (p<0.01). However, no such association could be found between acute kidney injury stage and amount of contrast media applied (in ml±SD) 0: 138±57, 1: 139±61; 2: 140±76; 3: 145±80 (p=0.5). Reduced initial glomerular filtration rate was associated with higher incidences of acute kidney injury while again no relation to amount of contrast media could be observed in subgroups ranked by initial glomerular filtration rate. A multivariate analysis confirmed these results: while left-heart-failure/cardiogenic shock (odds ratio (OR) 4.2, 95% confidence interval (CI) 3.3–5.5) as well as larger infarctions (peak creatine kinase >3000 U/l (OR 2.2, 95% CI 1.7–2.8)) were independently associated with a greater risk for acute kidney injury, amount of contrast media applied during angiography was not (150–250 ml, OR 0.95, 95% CI 0.8–1.2 (p=0.7), >250 ml, OR 1.3, 95% CI 0.8–2.0 (p=0.5)). Conclusions: Acute kidney injury, which was associated with elevated short- and long-term mortality rates, could be observed in 18% of patients admitted with STEMI. The present data suggest that severity and haemodynamic impairment due to STEMI rather than contrast-media-induced nephropathy is the key contributor for acute kidney injury in STEMI patients. The deleterious effect of the myocardial infarction itself on renal function can be explained through renal hypoperfusion, neurohormonal activation or other pathomechanisms that might have been underestimated in the past.

Evaluation of Existing Methods for Human Blood mRNA Isolation and Analysis for Large Studies

Aims Prior to implementing gene expression analyses from blood to a larger cohort study, an evaluation to set up a reliable and reproducible method is mandatory but challenging due to the specific characteristics of the samples as well as their collection methods. In this pilot study we optimized a combination of blood sampling and RNA isolation methods and present reproducible gene expression results from human blood samples. Methods The established PAXgeneTM blood collection method (Qiagen) was compared with the more recent TempusTM collection and storing system. RNA from blood samples collected by both systems was extracted on columns with the corresponding Norgen and PAX RNA extraction Kits. RNA quantity and quality was compared photometrically, with Ribogreen and by Real-Time PCR analyses of various reference genes (PPIA, β-ACTIN and TUBULIN) and exemplary of SIGLEC-7. Results Combining different sampling methods and extraction kits caused strong variations in gene expression. The use of PAXgeneTM and TempusTM collection systems resulted in RNA of good quality and quantity for the respective RNA isolation system. No large inter-donor variations could be detected for both systems. However, it was not possible to extract sufficient RNA of good quality with the PAXgeneTM RNA extraction system from samples collected by TempusTM collection tubes. Comparing only the Norgen RNA extraction methods, RNA from blood collected either by the TempusTM or PAXgeneTM collection system delivered sufficient amount and quality of RNA, but the TempusTM collection delivered higher RNA concentration compared to the PAXTM collection system. The established Pre-analytix PAXgeneTM RNA extraction system together with the PAXgeneTM blood collection system showed lowest CT-values, i.e. highest RNA concentration of good quality. Expression levels of all tested genes were stable and reproducible. Conclusions This study confirms that it is not possible to mix or change sampling or extraction strategies during the same study because of large variations of RNA yield and expression levels.

Whole-blood fatty acids and inflammation in European children: the IDEFICS Study

Background/Objectives:Fatty acids are hypothesized to influence cardiovascular disease risk because of their effect on inflammation. The aim of this study is to assess the relationship between whole-blood fatty acids (WBFAs) and high-sensitivity C-reactive protein (hs-CRP) in European children.Subjects/Methods:A total of 1401 subjects (697 boys and 704 girls) aged between 2 and 9 years from the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects in Children and infantS) study were measured in this cross-sectional analysis. The sample was divided into three categories of hs-CRP. Associations between WBFA and hs-CRP were assessed by logistic regression models adjusting for body mass index (BMI), country, age, breastfeeding, mother’s education and hours of physical activity.Results:Linoleic acid (LA) (P=0.013, 95% confidence interval (CI): 0.822–0.977) and sum of n-6 WBFA (P=0.029, 95% CI: 0.866–0.992) concentrations were associated with lower concentrations of hs-CRP in boys. In girls, a high ratio of eicosapentaenoic acid (EPA)/arachidonic acid (AA) was associated (P=0.018, 95% CI: 0.892–0.989) with lower hs-CRP concentrations. In contrast, sum of blood n-6 highly unsaturated fatty acids (P=0.012, 95% CI: 1.031–1.284), AA (P=0.007, 95% CI: 1.053–1.395) and AA/LA ratio (P=0.005, 95% CI: 1.102–1.703) were associated (P<0.05) with higher concentrations of hs-CRP in girls.Conclusions:The n-6 WBFAs (sum of n-6 FA and LA) were associated with lower hs-CRP in boys and with higher hs-CRP in girls (AA, sum of n-6 highly unsaturated and AA/LA ratio). More studies are needed to identify the optimal levels of WBFAs to avoid low-grade inflammation in children considering the differences by sex and BMI.

Collection of vaccination data in the German National Cohort

BackgroundData about the vaccination status of participants are required in epidemiological cohort studies whenever infection or immunity is considered as potential exposure or outcome. Within Pretest 2 of the German National Cohort (GNC) we therefore investigated the acceptance and feasibility of extracting vaccination status from vaccination certificates provided by the participants of the study.MethodsThis study was conducted in three study centers (Bremen, n = 73; Hamburg, n = 200; Hannover, n = 193). In order to test if an additional reminder would prevent participants from forgetting their vaccination certificates at home persons willing to participate in Pretest 2 were randomly assigned to one of three invitation groups (IG). About one third of the participants received either no further reminder (IG1), a reminder card together with the appointment letter (IG2) or a separate reminder card 4 days before the appointment (IG3). At the study center, vaccination data were scanned or copied and entered into a database using a unique identification number. Participants were also asked to fill in a short questionnaire to assess the completeness of the provided vaccination data. Additionally, in one of the three participating study centers, general practitioners (GP) were asked to provide vaccination data from their records following respective participants’ consent. Finally, we compared the influenza data from the vaccination certificates with the influenza data obtained from participants in Pretest 2 by use of a self-administered questionnaire (ID-Screen).ResultsDue to different starting dates of the study the intended reminder procedure was implemented only in Hamburg and Hannover. In Hamburg, significantly more vaccination certificates were submitted by the group which received the reminder card separately 4 days before the examination (IG3) compared to IG1 and IG2 (p = 0.04). In Hannover, in contrast, most vaccination certificates were brought by those who received the reminder card together with the appointment letter. Overall, the use of a reminder card had a positive but not significant effect as 89 % (185/209) of participants who received the reminder card submitted vaccination data versus 81 % (84/104) of participants who did not receive any reminder card (p = 0.06). Of all Pretest 2 participants in Hannover, 62 % (120/193) gave written consent for data collection by the GPs. In total, 114 practices were contacted of which 49 (43 %) sent vaccination data. All in all, 360 vaccination certificates with 5065 documented vaccinations were entered into a database, of which 4830 (95 %) were valid for analysis covering a period from 1946 to 2012. The comparison of influenza vaccination data from vaccination certificates to the remembered data from a self-completed questionnaire showed an agreement of data in 46 % (84/184) of cases (Kappa = 0.48). Influenza vaccinations were underreported in 4 % (7/170) of self-completed questionnaires.ConclusionThe reliable documentation of vaccinations within the context of the GNC proved to be feasible and thus recommendable at a large scale within the GNC as participants showed high willingness and compliance in providing available vaccination documents. An additional validation by means of documents provided by physicians seems to be possible for more than a quarter of participants. In order to maximize the likelyhood of participants’ of bringing their vaccination certificates it would be sufficient to send a reminder card together with the appointment letter.ZusammenfassungHintergrundDaten über den Impfstatus von Teilnehmern in epidemiologischen Studien werden immer dann benötigt, wenn Infektionen oder Immunität als mögliche Exposition oder Outcome betrachtet werden. Wir haben daher die Akzeptanz und Machbarkeit der Impfdatenerhebung durch Erfassung von Impfpässen im Rahmen des Pretest 2 der Nationalen Kohorte untersucht.MethodenDie Studie wurde in 3 Studienzentren (Bremen, n = 73; Hamburg, n = 200; Hannover, n = 193) durchgeführt. Um zu testen, ob eine zusätzliche Erinnerung die Bereitstellung der Impfpässe positiv beeinflusst, wurden Personen, die der Teilnahme an Pretest 2 der Nationalen Kohorte zustimmten, einer von drei verschiedenen Erinnerungsgruppen (IG) zugeteilt. Je ein Drittel der Teilnehmer erhielt entweder keine weitere Erinnerung (IG1), eine Erinnerungskarte zusammen mit der Terminbestätigung (IG2) oder eine Erinnerungskarte separat 4 Tage vor dem Untersuchungstermin (IG3). Im Studienzentrum wurden die mitgebrachten Impfpässe unter einem Pseudonym gescannt oder kopiert und in eine Datenbank übertragen. Teilnehmer wurden außerdem gebeten, einen kurzen Fragebogen zur Vollständigkeit der vorgelegten Impfdaten selbstständig auszufüllen. Die Studienteilnehmer in Hannover wurden zusätzlich um das Einverständnis gebeten, Impfdaten über die Hausärzte erheben zu dürfen. Darüber hinaus haben wir die Daten zu Influenzaimpfungen aus den Impfpässen mit den von den Pretest-2-Teilnehmern erinnerten Angaben zu erhaltenen Influenzaimpfungen aus einem Selbstausfüller (ID-Screen) verglichen.ErgebnisseAufgrund unterschiedlicher Startzeitpunkte der Studie wurde das Erinnerungsverfahren nur in den Studienzentren Hamburg und Hannover wie vorgesehen umgesetzt. In Hamburg wurden signifikant mehr Impfpässe in der Erinnerungsgruppe mit einer separat versendeten Erinnerungskarte 4 Tage vor dem Untersuchungstermin (IG3) mitgebracht, verglichen mit IG1 und IG2 (p = 0,04). In Hannover wurden dagegen die meisten Impfpässe von denjenigen vorgelegt, die die Erinnerungskarte zusammen mit der Terminbestätigung erhielten. Das Versenden einer Erinnerungskarte hat sich, unabhängig davon, ob sie zusammen mit der Terminbestätigung oder separat übermittelt wurde, positiv, jedoch nicht signifikant, auf das Mitbringen der Impfausweise ausgewirkt: Mit Erinnerungskarte haben 89 % (185/209) der Teilnehmer Impfpässe vorgelegt, ohne Erinnerungskarte 81 % (84/104) der Teilnehmer (p = 0,06). Der Datenerhebung über den Hausarzt stimmten 62 % (120/193) aller Pretest-2-Teilnehmer in Hannover zu. Von den 114 angeschriebenen Hausärzten haben 49 Ärzte (43 %) Impfdaten geschickt. 360 Impfpässe mit 5065 Einträgen wurden in eine Impfdatenbank eingegeben. Von diesen sind 4830 (95 %) verwertbar. Die Impfeinträge umfassen den Zeitraum von 1946 bis 2012. Der Vergleich von in den Impfpässen dokumentierten Influenzaimpfungen mit den im Selbstausfüller erinnerten Angaben zeigte eine Übereinstimmung der Daten in 46 % (84/184) der Fälle (Kappa = 0,48). Influenzaimpfungen wurden in 4 % der Fragebögen (7/170) untererfasst.SchlussfolgerungenDie hohe Bereitschaft und Zuverlässigkeit der Probanden, ihre Impfpässe vorzulegen, zeigte, dass auf diese Weise eine verlässliche Impfdokumentation im Rahmen der Nationalen Kohorte erfolgen und somit auch in größerem Umfang empfohlen werden kann. Auch erscheint die zusätzliche Validierung über die hausärztliche Dokumentation für über ein Viertel aller Probanden möglich. Um an das Mitbringen der Impfpässe zu erinnern, reicht ein ergänzender Satz in der Terminbestätigung, der standardmäßig eine farbige Erinnerungskarte beigelegt werden sollte.

The stem cell factor HMGA2 is expressed in non-HPV associated head and neck squamous cell carcinoma and predicts patient survival of distinct subsites.

Background: The transcription factor high-mobility AT-hook 2 (HMGA2) is involved in stem cell renewal and is expressed in many tumor tissues. Head and neck squamous cell carcinomas (HNSCC) comprise tumors of the upper aerodigestive tract and are characterized by high recurrence rates that represent a challenge to patient management. The study addresses the potential of HMGA2 as a molecular biomarker for HNSCC patient survival. Methods: Patients with HNSCC of the larynx, pharynx, tonsils, or oral cavity were recruited in a hospital-based case–control study (n = 202). Quantitative expression of HMGA2 in tumor tissues was measured by RT-PCR. In a 6- to 10-year follow-up, secondary cancers, vital status, and cause of death were ascertained. The HR and 95% confidence intervals (CI) for overall, tumor-specific, and progression-free survival were estimated by Cox proportional hazards with HMGA2 expression level as the independent variable. Results: High HMGA2 expression in tumor tissues of HNSCC patients was significantly correlated with negative HPV status (P = 0.01), and associated with shorter overall survival time. In Cox regression modeling, HMGA2 expression yielded a risk increase for overall and tumor-specific death in subsets of HNSCC patients, that is, laryngeal cancer patients (overall survival: HR = 4.00; 95% CI, 1.18–13.62) and in oral cancer patients (tumor-specific survival: HR = 2.88; 95% CI, 1.06–7.84), but not in patients with pharyngeal and tonsillar HNSCC. Conclusions: HMGA2 expression is associated with a risk increase for adverse outcomes in patients with HNSCC of the larynx and oral cavity. Impact: The understanding of stem cell signaling in HNSCC may offer new strategies for cancer treatment. Cancer Epidemiol Biomarkers Prev; 26(2); 197–205. ©2016 AACR.