247 research outputs found
Dietary sodium as a risk factor for osteoporosis:where is the evidence?
No full textNa-induced calciuria has been well documented and provides a physiological basis for the proposed role of dietary Na (or salt) as a risk factor for osteoporosis. However, the evidence is based primarily on acute salt-loading studies, and there are insufficient data on the effects of high salt intake on net Ca retention to predict long-term effects on bone health. Results of investigations on salt and bone turnover, as assessed by bone biomarkers, are inconsistent, but the large variations in inter-individual response to acute and chronic Na loading may be related to salt sensitivity. Results of cross-sectional and prospective investigations on high salt intake and long-term bone health are inconclusive, probably reflecting the difficulty of conducting such studies in free-living populations. However, the mean urinary Ca loss of 1 mmol/100 mmol Na suggests that chronic changes in salt intake may have large effects on Ca and bone balance, especially in individuals with a reduced capacity to compensate for Na-induced Ca loss. Investigating the relationship between salt intake and bone health requires a greater focus on whole diets (including components such as K, Mg, P and protein), reliable measures of salt intake, appropriate bone health outcome measures, and improved subject characterisation (e.g. salt sensitivity). The reasons for inter-individual variability should be explored using post-genomic techniques
Calcium bioavailability in relation to bone health
No full textA well established stable isotope technique exists for measuring calcium absorption from single foods and meals, but the long term effects of calcium on bone health cannot be assessed from acute bioavailability studies. Bone health depends primarily on the degree of mineralization, measured as bone mineral density (BMD), and phenotypic variations depend on genetic and environmental factors including calcium supply. Since almost all retained calcium is used for bone mineralization and remodeling, BMD can be used as a long-term (> six months) marker of dietary calcium bioavailability. However, BMD is a very insensitive marker of calcium bioavailability, so its use in dietary intervention studies is restricted to periods of significant bone growth or loss. Biochemical markers of bone metabolism may be used to predict the overall bioavailability of dietary calcium over a shorter time period (> four weeks), but they have a high coefficient of variation, so may not be appropriate for some dietary intervention studies. A group of European laboratories is currently developing an alternative approach using a long-lived radioisotope (41Ca) to label bone calcium and to directly measure the rate of calcium loss from urinary excretion data. The efficiency of calcium absorption is inversely related to intake; whole body balance of the mineral is dependent on rates of absorption and excretion and limited by calcium-binding substances in the gut. Dietary data and indirect measures of bone health indicate that bioavailability is important when habitual intakes are low, especially during periods of bone growth or loss. Further research is required to quantify the effects of major dietary modulators of calcium balance on bone health and to understand their relationship with genetic and physiological variables
Iron and calcium bioavailability of fortified foods and dietary supplements
No full textBioavailability is a key consideration when developing strategies for preventing mineral deficiencies through improved dietary supply. Factors that affect the bioavailability of iron and calcium, forms used for fortification and supplementation, and methods used to assess bioavailability are described. Illustrations of the impact of introducing iron-fortified foods in developing and industrialized countries are given, and the alternative approach of supplementation with iron and calcium is discussed
Use of compartmental analysis as a gold standard to compare against other methods for assessing fractional zinc absorption
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Schlussbericht Deutsches Zentrum für Lungenforschung (DZL)
No full textBei der im Folgenden dargestellten Pilotstudie handelt es sich um eine Erweiterung der wissenschaftlichen Fragestellung der bereits vom DZL-finanzierten ERT-BC Studie (FKZ82DZL14A2). Zurzeit gibt es noch keine systemischen Biomarker, die für ein frühes Therapieansprechen in der Klinik zur Anwendung kommen. Das Design der ERT-BC Studie, mit jeweils einem Untersuchungsarm für Chemostatika (Gruppe A) und Tyrosin-Kinase-Inhibitoren (TKI; Gruppe B) bietet ideale Voraussetzungen, um die Eignung von neuen Biomarkern zur frühen Erkennung und Verlauf des Therapieansprechens zu prüfen. Ziel der Studie sollte sein, ob mit Hilfe der hier untersuchten Biomarker ein oder mehrere Biomarker geeignet sind, um das frühe Therapieansprechen bei Patienten mit einem NSCLC im späten Stadium anzuzeigen. Da es sich hier um eine explorative Pilotstudie handelt, sollte ebenso berechnet werden, welche Fallzahlen nötig wären, um ein valides Vorhersagemodell zu erreichen. Das Studiendesign der ERT-BC Studie beruht dabei auf zwei Studienarmen. Hierbei wurde bei der Gruppe A (Chemotherapie) Serum und Plasma von Patienten vor der Behandlung (Tag -1) und am Tag nach der Behandlung (Tag +1) abgenommen. Bei den Patienten, die mit einem Tyrosinkinaseinhibitor (TKI) behandelt wurden (Gruppe B) wurden drei Zeitpunkte gewählt (Tag -1, +7 und +14), da davon ausgegangen wurde, dass die Medikamentengabe in Form von Tabletten zu einer verzögernden Aufnahme und Wirkung des TKIs führt. Die Biomarker wurden zu den entsprechenden Blutprobenzeitpunkten gemessen. Die Änderung der Messwerte vom Messzeitpunkt (+1, +7 oder +14) zum Baseline-Zeitpunkt (-1) wurde in Korrelation zur Änderung der Tumorlast gesetzt. Diese wurde bestimmt, indem das prätherapeutische sowie das erste CT-Bild nach der Therapie von einem Radiologen in der Thoraxklinik ausgewertet wurden. Mit Hilfe des Biostatistikers wurden die erhaltenen Daten ausgewertet. Hierbei gab es drei Auswertungen: I) Es wurde zu jedem einzelnen Marker zu jedem Zeitpunkt betrachtet, ob er eine signifikante Veränderung der Tumorgröße anzeigt. II) Es wurden alle Marker zueinander in Korrelation gesetzt, um zu untersuchen, wie gut die Marker untereinander korrelierten. III) Es wurde eine multivariate Analyse durchgeführt, um zu untersuchen, welche Markerkombinationen aus jeweils den besten 5 Markern zu welchem Zeitpunkt die besten Korrelationen zum Therapieansprechen lieferten.
Bei I) zeigte sich, dass keiner der Biomarker über alle drei gemessenen Zeitpunkte als Marker signifikant mit dem Ansprechen der Patienten korrelierte. Korrelationsanalysen der einzelnen Marker zueinander zeigten, dass durchaus Korrelationen zueinander bestanden (z.B. am Tag +7 zwischen Glycodelin und dem Level der detektierten Mutationen (r = 0.502) oder zwischen dem Level der Mutationen und GSH (r = 0.715)). Allerdings korrelierten die Werte nicht signifikant mit dem Ansprechen der Therapie. Bei der univariaten Analyse gab es insgesamt nur 5 Marker, die ein Signifikanzniveau < 0.05 bezüglich der Korrelation zur Tumorlast erreichten. Die multivariate Analysen ergaben, dass es durchaus mögliche Signaturen zu den einzelnen Zeitpunkten gibt, die das Ansprechen der Therapie gut wiedergeben. Zusammenfassend zeigte die explorative Studie hier großes Potential auf einem bisher kaum beschriebenen Feld. Allerdings muss hier erwähnt werden, dass die geringe Anzahl an Proben in Kombination den beiden Studienarmen und Detektionslimits dazu führte, dass die Ergebnisse mit einer großen statistischen Unsicherheit zu werten sind. Auf Empfehlung des Biostatistikers sollte die Gruppengröße der beiden Studienarme auf mindestens je 90 Patienten erweitert werden, um valide Ergebnisse zu erhalten
Life satisfaction and risk of chronic diseases in the European prospective investigation into cancer and nutrition (EPIC)-Germany study.
No full textOBJECTIVE: The aim of the study was to examine the prospective association between life satisfaction and risk of type 2 diabetes mellitus, myocardial infarction, stroke, and cancer. Previous studies suggested that psychosocial factors may affect the development of chronic diseases but the impact of positive attitudes, in particular life satisfaction, is yet to be determined. METHODS: The analysis included 50,358 participants of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Germany study in Potsdam and Heidelberg. Life satisfaction was assessed in a baseline interview and incident cases of chronic diseases were identified and verified during follow-up. Hazard ratios were calculated using Cox proportional hazards regression models that were systematically multivariable-adjusted for established risk factors and prevalent diseases. RESULTS: During an average of 8 years of follow-up 2,293 cases of cancer, 1,840 cases of type 2 diabetes mellitus, 440 cases of stroke, and 562 cases of myocardial infarction were observed. Women who were unsatisfied with life at baseline showed in all models a significantly increased risk of cancer (HR: 1.45; 95% CI: 1.18-1.78) and stroke (HR: 1.69; 95% CI: 1.05-2.73) as well as an increased risk of type 2 diabetes mellitus by trend across categories (p-trend=0.04) compared to women very satisfied with life. In men, a relationship between life satisfaction and stroke was found but did not persist after consideration of lifestyle factors and prevalent diseases. No significant association was observed between life satisfaction and risk of myocardial infarction. CONCLUSIONS: The results of this study suggest that reduced life satisfaction is related to the development of chronic diseases--particularly in women and partly mediated by established risk factors
Sex-specific and multivariable-adjusted hazard ratios (HR) and 95%-confidence intervals (CI) of myocardial infarction incidence according to life satisfaction within EPIC Germany.
No full text<p><b>Model 1</b>: Cox proportional hazards regression stratified by age and study center</p><p><b>Model 2</b>: model 1 with additional adjustment for smoking (never, former, current), alcohol intake (≤10 g/day, >10-40 g/day, >40 g/day), physical activity (active, moderately active, moderately inactive, inactive), education (none, primary school, technical school, secondary school, higher education/university), WHR, consumption of fruits & vegetables (g/day), red meat (g/day), and whole-grain bread (g/day)</p><p><b>Model 3</b>: model 2 with additional adjustment for prevalent hypertension and type 2 diabetes mellitus</p
Automated quantification of adipose and skeletal muscle tissue in whole-body MRI data for epidemiological studies
No full textIron absorption from a breakfast cereal: Effects of EDTA compounds and ascorbic acid
No full textSodium iron ethylenediaminetetracetic acid (NaFeEDTA) has been recommended for food fortification programmes to improve iron status but its performance in commercial products has not been evaluated. The effect of EDTA on iron absorption from fortified cornflakes, given as part of a typical Western breakfast, was determined in a double-blind randomised study with 20 non-anaemic female volunteers, using experimentally prepared iron compounds, enriched with 58Fe, and faecal monitoring. Five meals were compared: hydrogen reduced iron, hydrogen reduced iron plus Na2EDTA (molar ratio EDTA:Fe 1:2), hydrogen reduced iron plus NaFe(III)EDTA at two different molar ratios (EDTA:total Fe 1:3 and 1:2), and hydrogen reduced iron plus 15 mg ascorbic acid (ascorbic acid:Fe 1.3:1). The iron and EDTA compounds were accurately weighed into gelatine capsules and taken with unfortified cornflakes, semi-skimmed milk and tea on two consecutive days; the iron dose per meal was 3.75 mg. Iron absorption from all five test meals was measured in each volunteer with a minimum wash-out period of 2 weeks between tests. Geometric mean iron absorption (%) from the 5 tests was 14.1, 17.6, 20.6, 24.4 and 17.5 respectively (equivalent to 0.5–0.9 mg absorbed iron). There was a significantly higher iron absorption from the mixture of reduced iron and NaFe(III)EDTA (EDTA:Fe 1:2) than from reduced iron alone (p = 0.014). It is not known whether the higher absorption was from reduced iron or NaFeEDTA or both. Absorption was not increased significantly with NaFe(III)EDTA (EDTA:Fe 1:3), Na2EDTA (EDTA:Fe 1:2) or ascorbic acid (15 mg)
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