Reference intervals and percentiles for soluble transferrin receptor and sTfR/log ferritin index in healthy children and adolescents.

OBJECTIVES: Soluble transferrin receptor (sTfR) is a marker of both erythropoiesis and iron status and is considered useful for detecting iron deficiency, especially in inflammatory conditions, but reference intervals covering the entire pediatric age spectrum are lacking. METHODS: We studied 1,064 (48.5 % female) healthy children of the entire pediatric age spectrum to determine reference values and percentiles for sTfR and the ratio of sTfR to log-ferritin (sTfR-F index) using a standard immunoturbidimetric assay. RESULTS: Soluble TfR levels were highly age-specific, with a peak in infancy and a decline in adulthood, whereas the sTfR-F index was a rather constant parameter. There were positive linear relationships for sTfR with hemoglobin (Hb) (p=0.008) and transferrin (females p<0.001; males p=0.003). A negative association was observed between sTfR and ferritin in females (p<0.0001) and for transferrin saturation and mean corpuscular volume (MCV) in both sexes (both p<0.0001). We found a positive relationship between sTfR and body height, body mass index (BMI) and inflammatory markers (CrP p<0.0001; WBC p=0.0172), while sTfR-F index was not affected by inflammation. CONCLUSIONS: Soluble TfR values appear to reflect the activity of infant erythropoiesis and to be modulated by inflammation and iron deficiency even in a healthy cohort.

HbA1c percentiles and the association between BMI, age, gender, puberty, and HbA1c levels in healthy German children and adolescents.

OBJECTIVE: The measurement of glycated hemoglobin (HbA1c) represents one way to detect type 1 and 2 diabetes in children at an early stage. However, to date, variations in HbA1c levels are not fully understood, even in healthy children. With this in mind, the present study aimed to establish HbA1c reference values in healthy children and to investigate the influence of various independent variables. STUDY DESIGN AND METHODS: Two thousand four hundred fifty-five healthy children and adolescents aged between 0.5 and 18 years participated in the population-based cohort study LIFE Child, Germany. Age- and gender-dependent percentiles were estimated, enabling HbA1c values to be converted into standard deviation scores (SDS). Logistic regression models were applied to assess associations between HbA1c-SDS (as outcome) and age, gender, BMI, birth weight, physical activity, pubertal status, and socioeconomic status (SES; as explanatory variables). RESULTS: The mean HbA1c value was 31.79 mmol/mol or 5.06% (SD = 3.3 mmol/mol, SD = 0.3%). Positive associations with HbA1c values were identified for age (b = 0.09, p < 0.001), gender (b = 0.25, p = 0.007), and BMI-SDS (b = 0.06, p < 0.001). In addition, obesity was related to higher HbA1c values (b = 0.29, p < 0.001). Compared to prepuberty, the pubertal and postpubertal stages were associated with higher HbA1c levels. Furthermore, higher SES was associated with higher HbA1c-SDS (b = 0.01, p = 0.04). CONCLUSION: The present study established HbA1c reference values based on a large sample of healthy German children and adolescents. Age, gender, SES, pubertal stage, and BMI were found to be associated with higher HbA1c levels.

Dubiously increased FT4 and FT3 levels in clinically euthyroid patients: clinical finding or analytical pitfall?

OBJECTIVES: We systematically investigated normally or subclinically increased thyroid stimulating hormone (TSH) values associated with unexpectedly increased thyroxine (FT4) and free triiodothyronine (FT3) in findings of patients without any thyroid disease. Moreover, we looked for alternatives to overcome such states with an improved diagnostic procedure and to investigate the pathogenetic background of the respective patients. METHODS: Samples with TSH concentrations within the range of 0.4-10 mU/L combined with increased concentrations of FT4 (n=120; Cobas, Roche) were collected over a period of around six years. Cobas FT4 results were compared with measurements from Liaison (DiaSorin) and Architect (Abbott) FT4 assays. For further validation all samples were measured for total thyroxine (TT4) (Cobas, Roche). Finally, FT3 and TT3 as complementary parameters were measured in samples with leftover material. To overcome potential analytical disturbances from stimulating heterophilic antibodies, we used heterophilic blocking tubes (HBTs). RESULTS: From the 120 samples with increased FT4 concentrations by Cobas, 51/120 were also increased by Liaison, and 26/120 by Architect. However, the measurement of TT4 indicated only n=10/120 increased values. The number of increased FT3 (n=71) measurements was higher in Architect>Cobas>Liaison (28>27>9). TT3 levels of 70/71 samples were within the reference interval. HBTs were inappropriate to reduce unspecific immunoreactivity in our samples. No clear pathogenetic background could be elucidated in the anamnesis of individual patients. CONCLUSIONS: To overcome dubious constellations of TSH, FT4, and FT3, it is helpful to measure TT4 and TT3 for control or to use an immunoassay with an alternative assay design for the respective parameters.

Age-Dependent Reference Values for hs-Troponin T and NT-proBNP and Determining Factors in a Cohort of Healthy Children (The LIFE Child Study).

This study aimed to provide reliable pediatric reference values for N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitive Troponin T (hsTnT) obtained from a population of well children and investigate for associations with sex, pubertal status, body mass index (BMI), and serum lipid levels. We analyzed hsTnT and NT-proBNP values obtained from 4826 samples provided by 2522 children aged 0.25-18 years participating in a prospective longitudinal population-based cohort study, "LIFE child" in Leipzig, Germany (Poulain et al., Eur J Epidemiol 32:145-158, 2017). NT-proBNP values decreased throughout childhood from values over 400 ng/L at 3 months to 138 ng/L in females and 65 ng/L in males by 18 years of age. Values dropped rapidly with advancing pubertal stage. We found a strong association between lower NT-proBNP values and higher BMI or elevated serum lipids, the latter effect being more pronounced in males. For hsTnT levels, approximately half of the measurements were below the detection limit. However, 76% of those aged 3 months and 21% of those aged 6 months had values exceeding the adult cut-off limit. Females had slightly higher levels in the first 2 years of life but this was reversed during puberty. In males, there was an upward trend from pubertal stage 2 onward. We identified a positive association between hsTnT and BMI but a negative association with low-density lipoprotein (LDL) cholesterol and triglyceride levels in boys but not in girls. Based on a large number of healthy children, we have established reliable reference values for NT-proBNP and hsTnT for use in everyday clinical practice. We have also identified important associations between certain metabolic and cardiac markers.Clinical Trial Registration ClinicalTrial.gov (NCT02550236).

The novel cystatin C, lactate, interleukin-6, and N-terminal pro-B-type natriuretic peptide (CLIP)-based mortality risk score in cardiogenic shock after acute myocardial infarction.

BACKGROUND: Cardiogenic shock (CS) complicating acute myocardial infarction (AMI) still reaches excessively high mortality rates. This analysis is aimed to develop a new easily applicable biomarker-based risk score. METHODS AND RESULTS: A biomarker-based risk score for 30-day mortality was developed from 458 patients with CS complicating AMI included in the randomized CULPRIT-SHOCK trial. The selection of relevant predictors and the coefficient estimation for the prognostic model were performed by a penalized multivariate logistic regression analysis. Validation was performed internally, internally externally as well as externally in 163 patients with CS included in the randomized IABP-SHOCK II trial. Blood samples were obtained at randomization. The two trials are registered with ClinicalTrials.gov (NCT01927549 and NCT00491036), are closed to new participants, and follow-up is completed. Out of 58 candidate variables, the four strongest predictors for 30-day mortality were included in the CLIP score (cystatin C, lactate, interleukin-6, and N-terminal pro-B-type natriuretic peptide). The score was well calibrated and yielded high c-statistics of 0.82 [95% confidence interval (CI) 0.78-0.86] in internal validation, 0.82 (95% CI 0.75-0.89) in internal-external (temporal) validation, and 0.73 (95% CI 0.65-0.81) in external validation. Notably, it outperformed the Simplified Acute Physiology Score II and IABP-SHOCK II risk score in prognostication (0.83 vs 0.62; P < 0.001 and 0.83 vs. 0.76; P = 0.03, respectively). CONCLUSIONS: A biomarker-only score for 30-day mortality risk stratification in infarct-related CS was developed, extensively validated and calibrated in a prospective cohort of contemporary patients with CS after AMI. The CLIP score outperformed other clinical scores and may be useful as an early decision tool in CS.

Procalcitonin measured by three different assays is an excellent tumor marker for the follow-up of patients with medullary thyroid carcinoma.

OBJECTIVES: Procalcitonin (PCT) has been suggested as a tumor marker in patients with medullary thyroid carcinoma (MTC). Clinical application data in long term follow-up are missing. METHODS: 210 serum samples of 169 consecutive patients with MTC (92 sporadic, 77 hereditary, 158 postoperative follow-up, 11 preoperative) were collected between 2018 and 2020. Postoperative patients were stratified into three groups according to their disease status at the end of follow-up: cured (n=51, calcitonin (CT) levels < limit of quantitation), minimal residual disease (n=55, detectable CT and no metastases provable by imaging methods), metastatic disease (n=52). In five patients CT and PCT were measured while on therapy with tyrosine kinase inhibitors (TKI). CT was analyzed by the Roche ECLIA, PCT by three assays from Roche, PES, Abbott. RESULTS: The mean ± SD values seen with the three PCT assays in the MTC response groups, cured: <0.06, 0.016 ± 0.007, 0.014 ± 0.007 ng/mL, minimal residual disease: 0.511 ± 0.800, 0.389 ± 0.687, 0.341 ± 0.614 ng/mL, metastatic disease 109 ± 202, 60.4 ± 110, 63.3 ± 115 ng/mL correlate well with the CT results in these groups: cured <1.0 pg/mL, minimal residual disease 91.3 ± 121.5 pg/mL, metastatic disease 14,489 ± 30,772 pg/mL. There was a significant correlation (p<0.001) between the three PCT assays (Roche/PES r=0.970, Roche/Abbott r=0.976, Abbott/PES r=0.995). In the course of treatment with TKI both CT and PCT reflected clinical state. Preoperative PCT in hereditary MTC has the same diagnostic validity than CT. CONCLUSIONS: PCT measured with three different immunoassays is as good as the standard tumor marker CT in the follow-up of MTC but has a superior analytical stability.

The effect of depressive symptomatology on the association of vitamin D and sleep.

BACKGROUND: Sleep disorders and vitamin D deficiency are highly prevalent health problems. Few studies examined the effect of vitamin D concentrations on objectively measured sleep with high methodological quality and temporal proximity. Previous analysis within the LIFE-Adult-Study suggested that a lower concentration of serum vitamin D was associated with both shorter and later night sleep. However, no conclusion about underlying mechanisms could be drawn. We addressed the question whether this relationship is explained by the presence of depressive syndromes, which are linked to both vitamin D deficiency and sleep disturbances. METHODS: It was investigated whether the association of vitamin D concentrations and night sleep parameters is mediated or moderated by depressive symptomatology. We investigated a subset (n = 1252) of the community sample from the LIFE-Adult-Study, in which sleep parameters had been objectively assessed using actigraphy, based on which two sleep parameters were calculated: night sleep duration and midsleep time. Serum 25(OH) D concentrations were measured using an electrochemiluminescence immunoassay. Depressive symptomatology was evaluated with the Centre for Epidemiological Studies Depression Scale. The mediation effect was analyzed by using Hayes' PROCESS macro tool for SPSS for Windows. RESULTS: The depressive symptomatology was neither significantly associated with night sleep duration nor midsleep time. The associations between vitamin D concentrations and night sleep duration/midsleep time through mediation by depressive symptomatology were not significant. Corresponding moderator analyses were also non-significant. CONCLUSION: The associations between vitamin D concentrations and night sleep parameters (sleep duration and midsleep time) seem to be neither mediated nor moderated by depressive symptomatology.

Cystatin C serum levels in healthy children are related to age, gender, and pubertal stage.

BACKGROUND: This study aims to establish age- and gender-specific cystatin C (CysC) reference values for healthy infants, children, and adolescents and to relate them to pubertal stage, height, weight, and body mass index (BMI). METHODS: Serum CysC and creatinine levels of 6217 fasting, morning venous blood samples from 2803 healthy participants of the LIFE Child study (age 3 months to 18 years) were analyzed by an immunoassay. Recruitment started in 2011; 1636 participants provided at least one follow-up measurement. Percentiles for CysC were calculated. Age- and gender-related effects of height, weight, BMI, and puberty status were assessed through linear regression models. RESULTS: Over the first 2 years of life, median CysC levels decrease depending on height (ß = - 0.010 mg/l/cm, p < 0.001) and weight (ß = - 0.033 mg/l/kg, p < 0.001) from 1.06 to 0.88 mg/l for males and from 1.04 to 0.87 mg/l for females. Following the second year of age, the levels remain stable for eight years. From 11 to 14 years of age, there is an increase of median CysC levels in males to 0.98 mg/l and a decrease in females to 0.86 mg/l. The change is associated with puberty (ß = 0.105 mg/l/Tanner stage, p < 0.001 in males and ß = - 0.093 mg/l/Tanner stage, p < 0.01 in females) and in males with height (ß = 0.003 mg/l/cm, p < 0.001). CONCLUSIONS: CysC levels depend on age, gender, and height, especially during infancy and puberty. We recommend the use of age- and gender-specific reference values for CysC serum levels for estimating kidney function in clinical practice.

Stress biomarkers in minimally invasive and conventional colorectal resections.

INTRODUCTION: Any surgical procedure develops a stress situation for the patient, which can modulate the individual outcome. At present, there is only limited information about stress response in colorectal resections by laparoscopic compared to conventional surgery. Therefore, our objectives were the feasibility and the investigation of stress biomarkers including copeptin and steroid hormones before, during and after colorectal surgery. METHODS: Eleven patients underwent minimally invasive and ten patients conventionally open colorectal surgery. Blood samples were collected before, during and 24 h after surgery and copeptin, NT-proBNP, cortisol, cortisone, interleukin-6 and glucose were analyzed. RESULTS: Both, minimally invasive and conventional-open colorectal surgery caused a fast but heterogeneous response of stress biomarkers. However, the postoperative decrease of cortisol, cortisone and glucose differed between both groups. The stress biomarkers decreased faster down to baseline after minimally invasive surgery, while in open surgery cortisol, cortisone and glucose did not return to baseline within 24 h after operation. CONCLUSIONS: We show in this feasibility study for the first time an increase of copeptin in combination with glucocorticoids as stress biomarkers by open surgery compared to minimally invasive procedures in patients undergoing colorectal surgery. Exceeding an individual threshold of 'stress burden' may have unfavorable effects on the long-time clinical outcome.

Effects of resveratrol on memory performance, hippocampus connectivity and microstructure in older adults - A randomized controlled trial.

INTRODUCTION: The polyphenol resveratrol has been suggested to exert beneficial effects on memory and the aging hippocampus due to calorie-restriction mimicking effects. However, the evidence based on human interventional studies is scarce. We therefore aimed to determine the effects of resveratrol on memory performance, and to identify potential underlying mechanisms using a broad array of blood-based biomarkers as well as hippocampus connectivity and microstructure assessed with ultra-high field magnetic resonance imaging (UHF-MRI). METHODS: In this double-blind, randomized controlled trial, 60 elderly participants (60-79 years) with a wide body-mass index (BMI) range of 21-37 kg/m2 were randomized to receive either resveratrol (200 mg/day) or placebo for 26 weeks (registered at ClinicalTrials.gov: NCT02621554). Baseline and follow-up assessments included the California Verbal Learning Task (CVLT, main outcome), the ModBent task, anthropometry, markers of glucose and lipid metabolism, inflammation and neurotrophins derived from fasting blood, multimodal neuroimaging at 3 and 7 T, and questionnaires to assess confounding factors. RESULTS: Multivariate repeated-measures ANOVA did not detect significant time by group effects for CVLT performance. There was a trend for preserved pattern recognition memory after resveratrol, while performance decreased in the placebo group (n.s., p = 0.07). Further exploratory analyses showed increases in both groups over time in body fat, cholesterol, fasting glucose, interleukin 6, high sensitive C-reactive protein, tumor necrosis factor alpha and in mean diffusivity of the subiculum and presubiculum, as well as decreases in physical activity, brain-derived neurotrophic factor and insulin-like growth factor 1 at follow-up, which were partly more pronounced after resveratrol. DISCUSSION: This interventional study failed to show significant improvements in verbal memory after 6 months of resveratrol in healthy elderly with a wide BMI range. A non-significant trend emerged for positive effects on pattern recognition memory, while possible confounding effects of unfavorable changes in lifestyle behavior, neurotrophins and inflammatory markers occurred. Our findings also indicate the feasibility to detect (un)healthy aging-related changes in measures of hippocampus microstructure after 6 months using 7T diffusion MRI. More studies incorporating a longer duration and larger sample size are needed to determine if resveratrol enhances memory performance in healthy older adults.

Gingivitis and lifestyle influences on high-sensitivity C-reactive protein and interleukin 6 in adolescents.

AIM: This cross-sectional study was repeated at two time points and investigated the influence of gingivitis, smoking and body mass index (BMI) on the systemic inflammatory markers high-sensitivity C-reactive protein (hs-CRP) and interleukin 6 (IL6) in 10- and 15-year-olds. MATERIALS AND METHODS: The study sample of two birth cohorts, i.e. GINIplus and LISAplus, from the Munich centre consisted of 806 and 846 subjects who were evaluated at 10- and 15-year follow-ups respectively. Children and their parents completed questionnaires on participant-related lifestyle information. Gingivitis was measured at the sextant level using a simplified sulcus-bleeding index. Serum hs-CRP and IL6 levels were obtained from blood samples. Multiple logistic regressions adjusting for lifestyle-related factors and other confounders were performed to assess associations between the specified variables. RESULTS: There were no associations between gingivitis and the inflammatory markers hs-CRP and IL6 in 10-year-olds. In 15-year-olds, gingivitis (aOR: 2.17; 95% CI: 1.25-3.77); daily smoking (aOR: 6.27; 95% CI: 1.39-28.39); and being overweight/obese (aOR: 4.95; 95% CI: 0.73-33.68) were identified as significantly influencing factors for elevated hs-CRP values. Oral hygiene did not influence hs-CRP. CONCLUSION: In this study, hs-CRP was positively associated with gingivitis, smoking daily and overweight/obesity among 15-year-olds.

Immunoassay or LC-MS/MS for the measurement of salivary cortisol in children?

BACKGROUND: Dysregulation of the adrenal cortex has been assessed with measurement of salivary cortisol. So far salivary cortisol is routinely measured with immunoassay (IA). However, liquid chromatography-tandem mass spectrometry (MS) is known to offer better specificity. We compared the concentrations of salivary cortisol measured by MS and IA at basal and stress induced conditions and evaluated reasons for the difference in method-dependent cortisol results. METHODS: Saliva samples (n=2703) were collected from 169 children (age range: 8-14 years; 81 healthy children; 55 with internalizing and 33 with externalizing disorders) under circadian conditions and during the Trier Social Stress Test for Children (TSST-C). Biochemical analyses were performed with MS for cortisol and cortisone, IA (IBL, RE62011) for cortisol, and enzyme kinetic assay for α-amylase. RESULTS: MS and IA showed mostly comparable results for circadian activity and TSST-C response with similar statistical power. However, IA measured cortisol concentrations about 2.39-fold higher than MS. We found that this difference in measured values between MS and IA was mainly due to different standardization of IA compared to MS. In addition, at cortisol IA concentration below 5 nmol/L, cross-reactivity with cortisone was found to contribute to the lower concordance between MS and IA. CONCLUSIONS: Immunoassay and LC-MS/MS were largely comparable in the interpretation of salivary cortisol dynamics in stress research. But the IA method revealed a restricted accuracy in the measuring range below 5 nmol/L.

Creatine kinase serum levels in children revisited: New reference intervals from a large cohort of healthy children and adolescents.

BACKGROUND: Creatine Kinase (CK) has become increasingly important in pediatrics as a commonly used laboratory screening parameter for neuromuscular diseases. Recent research suggests that hyperCKemia in children is not always associated with pathology and can occur due to several reasons. Little is known of various clinical factors that may influence CK throughout child development. OBJECTIVE: This study aimed to establish reliable age- and sex-specific reference ranges for serum CK levels in healthy infants, children, and adolescents. In addition, the effect of puberty, oral contraceptive (OC) use as well as steroid hormones on CK was examined. MATERIALS AND METHODS: The data was collected from subjects of the longitudinal population-based "LIFE Child"-cohort between 2011 and 2016 in Leipzig, Germany. 5238 blood samples of 2707 healthy children, aged between 0.14 months and 18 years, were analyzed. RESULTS: Serum CK levels raised during the first year of life, peaking shortly after age one (P50girls = 2.7 µkat/L, P50boys = 2.90 µkat/L). There was a pronounced difference in the 97.5th percentile between boys and girls during adolescence with its maximum at age 18 (P97.5girls = 5.74 µkat/L, P97.5boys= 14.48 µkat/L). Also, mean CK serum levels were significantly higher in boys (bboys = 0.29, pboys < 0.001). Intake of oral contraceptives (OC), extreme underweight, underweight and obesity revealed a significant inverse correlation with CK serum levels. CONCLUSION: Age, sex, OC intake and weight status affect serum CK levels, particularly during infancy and puberty. We recommend the use of age- and sex-specific reference values for CK serum levels to assess the clinical relevance of measurements.

Influence of growth and metabolic markers on hs-troponin T and NT-proBNP levels in healthy children.

Background and objectives: As part of the LIFE Child study, we previously described the associations between N-terminal-pro-hormone brain natriuretic peptide (NT-proBNP) and hs-troponin T (hs-TnT) levels and an individual's sex, age and pubertal status, as well as with body mass index (BMI) and serum lipid levels. For NT-proBNP, we found inverse associations with advancing puberty, increasing BMI and serum lipid levels. These findings led us to further question the putative influences of the developing individual's metabolic and growth status as represented by levels of insulin-like growth factor-1 (IGF-1) and IGF-1-binding protein-3 (IGF-BP3) as well as hemoglobin A1c (HbA1c) and Cystatin C (CysC). Material and methods: Serum values, medical history and anthropometric data provided by 2522 children aged 0.25-18 years were collected and analyzed as per study protocol. Results: A strong negative association between NT-proBNP values and IGF-1, IGF-BP3 and HbA1c levels was identified. For IGF-BP3, this interaction was modulated by sex and age, for HbA1c only by age. For hs-TnT, a positive association was found with IGF-BP3, IGF-1 and CysC. The association between hs-TnT and IGF-1 was sex dependent. The association between CysC and hs-TnT was stronger in girls, but the interaction with age was only seen in boys. Between hs-TnT and HbA1c, the association was significantly negative and modulated by age. Conclusion: Based on our large pediatric cohort, we could identify age- and sex-dependent interactions between the metabolic status represented by IGF-1, IGF-BP3, CysC and HbA1c levels and the cardiac markers NT-proBNP and hs-TnT.

Pediatric reference values of alkaline phosphatase: Analysis from a German population-based cohort and influence of anthropometric and blood parameters.

BACKGROUND: Due to different growth and metabolic processes, reference values of alkaline phosphatase (AP) for children aged 3 month to 18 years are dependent on age and sex. They are not constant and differ from those of adults due to the growth processes taking place. Accordingly, reference levels of AP continuous across these ages were generated for boys and girls based on of a large German health- and population-based study, LIFE Child. We considered AP at different growth and Tanner stages and additionally its association with other anthropometric parameters. The association between AP and BMI was of particulary great interest due to controversial literature on this topic. The role of AP in liver metabolism was investigated by examining ALAT, ASAT, and GGT. METHODS: 3976 healthy children (12,093 visits) were included from the LIFE Child study from 2011 to 2020. The subjects´ age ranged from 3 months to 18 years. Serum samples from 3704 subjects (10,272 cases, 1952 boys and 1753 girls) were analysed for AP after applying specific exclusion criteria. After calculating of reference percentiles, associations between AP and height-SDS, growth velocity, BMI-SDS, Tanner stage and the liver enzymes ALAT, ASAT and GGT were examined via linear regression models. RESULTS: In the continuous reference levels, AP showed a first peak during the first year of life, followed by a plateau at a lower level until the start of puberty. In girls, AP increased beginning at the age 8, with a peak around 11 years, in boys beginning at the age 9, with a peak around age 13. Afterwards, AP values decreased continuously until age 18. In Tanner stages 1 and 2, AP levels did not differ between the two sexes. We found a strong positive association between AP-SDS and BMI-SDS. We also observed a significantly positive association between AP-SDS and height-SDS, which was stronger in boys than in girls. We found different intensities in the associations of AP with growth velocity depending on age group and sex. Furthermore, we found a significantly positive association between ALAT and AP in girls but not in boys, whereas ASAT-SDS and GGT-SDS were significantly positively associated with AP-SDS in both sexes. CONCLUSION: Sex and age, but also BMI may act as confounding factors for AP reference ranges. Our data confirm the remarkable association between AP and growth velocity (or height-SDS, respectively) during infancy and puberty. In addition, we were able to specify the associations between AP and ALAT, ASAT, and GGT and their differences in both sexes. These relations should be considered when evaluating liver and bone metabolism markers, especially in infancy.

Biomarkers for Non-Invasive Stratification of Coronary Artery Disease and Prognostic Impact on Long-Term Survival in Patients with Stable Coronary Heart Disease.

Knowledge about cardiac and inflammatory biomarkers in patients with stable coronary artery disease (CAD) is limited. To address this, we analyzed 3072 patients (36% female) with a median follow-up of 10 years in the Leipzig LIFE Heart Study with suspected CAD with coronary angiography. Selected biomarkers included troponin T (hsTNT), N-terminal pro B-type natriuretic peptide (NT-proBNP), copeptin, C-reactive protein (hsCRP), and interleukin-6 (IL-6). Patients were stratified by CAD severity: CAD0 (no sclerosis), CAD1 (non-obstructive, i.e., stenosis < 50%), and CAD2 (≥one stenosis ≥ 50%). Group comparison (GC) included GC1: CAD0 + 1 vs. CAD2; GC2: CAD0 vs. CAD1 + 2. CAD0, CAD1, and CAD2 were apparent in 1271, 631, and 1170 patients, respectively. Adjusted for classical risk factors, hs-cTnT, NT-proBNP, and IL-6 differed significantly in both GC and hsCRP only in GC2. After multivariate analysis, hs-cTnT, NT-proBNP, and IL-6 remained significant in GC1. In GC2, hs-cTnT (p < 0.001) and copeptin (p = 0.014) reached significance. Ten-year survival in groups CAD0, CAD1, and CAD2 was 88.3%, 77.3%, and 72.4%. Incorporation of hs-cTnT, NT-proBNP, copeptin, and IL-6 improved risk prediction (p < 0.001). The studied cardiac and inflammatory biomarkers enable fast and precise non-invasive identification of mortality risk in CAD patients, allowing the tailoring of primary and secondary CAD prevention.

Pediatric Reference Intervals for Thyrotropin, Free Triiodothyronine, and Free Thyroxine and the Relevance of Body Mass Index and Puberty in Measurement Interpretation.

Background: The present study aimed to establish age- and sex-specific reference intervals for serum concentrations of thyrotropin (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) in healthy children and adolescents. Additionally, we investigated the association of TSH, fT3, and fT4 with putative influencing factors, such as sex, body mass index (BMI), and puberty. Methods: A total of 9404 blood serum samples from 3140 children and adolescents without thyroid affecting diseases were included in determining TSH, fT3, and fT4 levels and age- and sex-specific reference ranges. To investigate the association of TSH, fT3, and fT4 with age, sex, weight status, and the role of puberty-based changes, the hormone levels and BMI values were converted to standard deviation scores (SDS). Results: In general, TSH, fT3, and fT4 were found to be age- and sex-dependent. Puberty was accompanied by decreased TSH, decreased fT3 with a temporary peak in males, and a temporary nadir of fT4 in Tanner stage 3 for both sexes. BMI-SDS was positively associated with TSH-SDS (ß = 0.081, p < 0.001); the effect was more pronounced in overweight subjects (ß = 0.142, p < 0.01) and insignificantly negative in underweight subjects (ß = -0.047, p > 0.05). BMI-SDS was positively associated with fT3-SDS (ß = 0.066, p < 0.001) and negatively associated with fT4-SDS (ß = -0.135, p < 0.001), with the effect insignificantly less negative in overweight children (ß = -0.055, p > 0.05). Conclusions: Age- and sex-specific reference intervals are important for the interpretation of measurements of TSH, fT3, and fT4 in children and adolescents. Influencing factors such as BMI and puberty should be taken into consideration when using measurements of TSH and thyroid hormones in the diagnosis, treatment, and monitoring of thyroid diseases. Clinical Trial Registration number: NCT02550236.

Folate and Cobalamin Serum Levels in Healthy Children and Adolescents and Their Association with Age, Sex, BMI and Socioeconomic Status.

This study proposes age- and sex-specific percentiles for serum cobalamin and folate, and analyzes the effects of sex, age, body mass index (BMI), and socioeconomic status (SES) on cobalamin and folate concentrations in healthy children and adolescents. In total, 4478 serum samples provided by healthy participants (2 months-18.0 years) in the LIFE (Leipzig Research Centre for Civilization Diseases) Child population-based cohort study between 2011 and 2015 were analyzed by electrochemiluminescence immunoassay (ECLIA). Continuous age-and sex-related percentiles (2.5th, 10th, 50th, 90th, 97.5th) were estimated, applying Cole's LMS method. In both sexes, folate concentrations decreased continuously with age, whereas cobalamin concentration peaked between three and seven years of age and declined thereafter. Female sex was associated with higher concentrations of both vitamins in 13- to 18-year-olds and with higher folate levels in one- to five-year-olds. BMI was inversely correlated with concentrations of both vitamins, whilst SES positively affected folate but not cobalamin concentrations. To conclude, in the assessment of cobalamin and folate status, the age- and sex-dependent dynamic of the respective serum concentrations must be considered. While BMI is a determinant of both vitamin concentrations, SES is only associated with folate concentrations.

Inflammation and the Association of Vitamin D and Depressive Symptomatology.

Depression and vitamin D deficiency are major public health problems. The existing literature indicates the complex relationship between depression and vitamin D. The purpose of this study was to examine whether this relationship is moderated or mediated by inflammation. A community sample (n = 7162) from the LIFE-Adult-Study was investigated, for whom depressive symptoms were assessed via the German version of CES-D scale and serum 25-hydroxyvitamin D (25(OH)D) levels and inflammatory markers (IL-6 and CRP levels, WBC count) were quantified. Mediation analyses were performed using Hayes' PROCESS macro and regression analyses were conducted to test moderation effects. There was a significant negative correlation between CES-D and 25(OH)D, and positive associations between inflammatory markers and CES-D scores. Only WBC partially mediated the association between 25(OH)D levels and depressive symptoms both in a simple mediation model (ab: -0.0042) and a model including covariates (ab: -0.0011). None of the inflammatory markers showed a moderation effect on the association between 25(OH)D levels and depressive symptoms. This present work highlighted the complex relationship between vitamin D, depressive symptoms and inflammation. Future studies are needed to examine the effect of vitamin D supplementation on inflammation and depressive symptomatology for causality assessment.

The Diagnostic Performance of Interleukin-6 and C-Reactive Protein for Early Identification of Neonatal Sepsis.

Interleukin-6 (IL-6) and C-reactive protein (CRP) are being used for diagnosis of sepsis. However, studies have reported varying cut-off levels and diagnostic performance. This study aims to investigate the optimal cut-off levels and performance of IL-6 and CRP for the diagnosis of neonatal sepsis. The study was conducted at the University Hospital of Leipzig, Germany from November 2012 to June 2020. A total of 899 neonates: 104 culture proven sepsis, 160 clinical sepsis, and 625 controls were included. Blood culture was performed using BacT/ALERT 3D system. IL-6 and CRP were analyzed by electrochemiluminescent immunoassay and immunoturbidimetric assay, respectively. Data were analyzed using SPSS 20 statistical software. Among neonates with proven sepsis, the optimal cut-off value of IL-6 was 313.5 pg/mL. The optimal cut-off values for CRP in 5 days serial measurements (CRP1, CRP2, CRP3, CRP4, and CRP5) were 2.15 mg/L, 8.01 mg/L, 6.80 mg/L, 5.25 mg/L, and 3.72 mg/L, respectively. IL-6 showed 73.1% sensitivity, 80.2% specificity, 37.6% PPV, and 94.8% NPV. The highest performance of CRP was observed in the second day with 89.4% sensitivity, 97.3% specificity, 94.5% PPV, and 98.3% NPV. The combination of IL-6 and CRP showed increase in sensitivity with decrease in specificity. In conclusion, this study defines the optimal cut-off values for IL-6 and CRP. The combination of IL-6 and CRP demonstrated increased sensitivity. The CRP 2 at cut-off 8.01 mg/L showed the highest diagnostic performance for identification of culture negative clinical sepsis cases. We recommend the combination of IL-6 (≥313.5 pg/mL) and CRP1 (≥2.15 mg/L) or IL-6 (≥313.5 pg/mL) and CRP2 (≥8.01 mg/L) for early and accurate diagnosis of neonatal sepsis. The recommendation is based on increased sensitivity, that is, to minimize the risk of any missing cases of sepsis. The CRP2 alone at cut-off 8.01 mg/L might be used to identify clinical sepsis cases among culture negative sepsis suspected neonates in hospital settings.