Role of Gut Microbe Composition in Psychosocial Symptom Response to Exercise Training in Breast Cancer Survivors (ROME) study: protocol for a randomised controlled trial

INTRODUCTION

Breast cancer survivors have an increased risk for chronic fatigue and altered gut microbiota composition, both with negative health and quality of life affects. Exercise modestly improves fatigue and is linked to gut microbial diversity and production of beneficial metabolites. Studies suggest that gut microbiota composition is a potential mechanism underlying fatigue response to exercise. Randomised controlled trials testing the effects of exercise on the gut microbiome are limited and there is a scarcity of findings specific to breast cancer survivors. The objective of this study is to determine if fitness-related modifications to gut microbiota occur and, if so, mediate the effects of aerobic exercise on fatigue response.

METHODS AND ANALYSIS

The research is a randomised controlled trial among breast cancer survivors aged 18-74 with fatigue. The primary aim is to determine the effects of aerobic exercise training compared with an attention control on gut microbiota composition. The secondary study aims are to test if exercise training (1) affects the gut microbiota composition directly and/or indirectly through inflammation (serum cytokines), autonomic nervous system (heart rate variability) or hypothalamic-pituitary-adrenal axis mediators (hair cortisol assays), and (2) effects on fatigue are direct and/or indirect through changes in the gut microbiota composition. All participants receive a standardised controlled diet. Assessments occur at baseline, 5 weeks, 10 weeks and 15 weeks (5 weeks post intervention completion). Faecal samples collect the gut microbiome and 16S gene sequencing will identify the microbiome. Fatigue is measured by a 13-item multidimensional fatigue scale.

ETHICS AND DISSEMINATION

The University of Alabama at Birmingham Institutional Review Board (IRB) approved this study on 15 May 2019, UAB IRB#30000320. A Data and Safety Monitoring Board convenes annually or more often if indicated. Findings will be disseminated in peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT04088708.

Breast cancer survivors' exercise preferences change during an exercise intervention are associated with post-intervention physical activity

PURPOSE

Exercise program preferences are important for designing physical activity (PA) interventions; yet may change following an intervention. Further, the relationship between preferences and PA behavior change is unclear. This study evaluated exercise program preferences among breast cancer survivors (BCS) before and after a behavioral intervention and associations between program preferences and PA change.

METHODS

BCS were randomized to the BEAT Cancer intervention (n = 110) or written materials (n = 112). Questionnaires assessed exercise program preferences. Minutes per week of moderate-to-vigorous PA (MVPA) were accelerometer-measured and self-reported at baseline (M0), post-intervention (M3), and 3-month follow-up (M6).

RESULTS

At M0, the majority of intervention group participants preferred exercising with others (62%) yet shifted to preferring exercising alone (59%) at M3 (p < 0.001). Furthermore, preferring exercising with others at M0 was associated with greater increases in self-reported MVPA between M0 and M6 (124.2 ± 152 vs. 53.1 ± 113.8, p = 0.014). BCS preferring facility-based exercise decreased after the BEAT Cancer intervention (14% vs. 7%, p = 0.039) and preferring exercising at home/had no preference at M0 had greater improvements in accelerometer-measured MVPA from M0 to M3 (74.3 ± 118.8 vs. -2.3 ± 78.4, p = 0.033) and M0 to M6 (44.9 ± 112.8 vs. 9.3 ± 30.4, p = 0.021). Exercise program preferences regarding mode of counseling, training supervision, and type of exercise changed from M0 to M3 but were not associated with changes in MVPA.

CONCLUSION

Findings suggest BCS exercise program preferences may change after an intervention and be associated with changes in MVPA. Understanding the role of PA preferences will better inform the design and success of PA behavior change interventions. ClinicTrials.gov, ClinicalTrials.gov number: NCT00929617.

Breast Cancer Survivors' Exercise Preferences Change During an Exercise Intervention and are associated with Post-Intervention Physical Activity

Purpose Exercise program preferences are important for designing physical activity (PA) interventions; yet may change following an intervention. Further, the relationship between preferences and PA behavior change is unclear. This study evaluated exercise program preferences among breast cancer survivors (BCS) before and after a behavioral intervention and associations between program preferences and PA change. Methods BCS were randomized to the BEAT Cancer intervention (n = 110) or written materials (n = 112). Questionnaires assessed exercise program preferences. Minutes per week of moderate-to-vigorous PA (MVPA) were accelerometer-measured and self-reported at baseline (M0), post-intervention (M3), and 3-month follow-up (M6). Results At M0, the majority of intervention group participants preferred exercising with others (62%) yet shifted to preferring exercising alone (59%) at M3 ( p  < 0.001). Furthermore, preferring exercising with others at M0 was associated with greater increases in self-reported MVPA between M0 and M6 (124.2 ± 152 vs. 53.1 ± 113.8, p = 0.014). BCS preferring facility-based exercise decreased after the BEAT Cancer intervention (14% vs. 7%, p  = 0.039) and preferring exercising at home/had no preference at M0 had greater improvements in accelerometer-measured MVPA from M0 to M3 (74.3 ± 118.8 vs. -2.3 ± 78.4, p = 0.033) and M0 to M6 (44.9 ± 112.8 vs. 9.3 ± 30.4, p = 0.021). Exercise program preferences regarding mode of counseling, training supervision, and type of exercise changed from M0 to M3 but were not associated with changes in MVPA. Conclusion Findings suggest BCS exercise program preferences may change after an intervention and be associated with changes in MVPA. Understanding the role of PA preferences will better inform the design and success of PA behavior change interventions. ClinicTrials.gov, ClinicalTrials.gov number: NCT00929617.

Moderators of physical activity and quality of life response to a physical activity intervention for breast cancer survivors

PURPOSE

Moderate-to-vigorous physical activity (MVPA) can improve the quality of life (QoL) for breast cancer survivors (BCS), yet, most do not achieve 150 + weekly minutes of MVPA. This study investigated moderators of response to a physical activity (PA) behavior change intervention for BCS.

METHODS

BCS (N = 222) were randomized to the 3-month intervention (BEAT Cancer) or usual care. Measurements occurred at baseline, post-intervention, and 3 months post-intervention. Measures included accelerometry, self-reported MVPA, and Functional Assessment of Cancer Therapy (FACT-General, FACT-Breast, physical well-being (PWB), social well-being (SWB), emotional well-being (EWB), functional well-being (FWB), additional concerns (AC), and Trial Outcome Index (TOI)).

RESULTS

Adjusted linear mixed-model analyses indicated individuals ≤ 24 months post-diagnosis and who were single reported smaller increases in weekly self-reported MVPA than those > 24 months (44.07 vs 111.93) and partnered (- 16.24 vs. 49.16 min), all p < 0.05. As for QoL, participants < 12 months post-diagnosis who received chemotherapy experienced smaller improvements than those ≥ 12 months in FACT-General, FACT-Breast, PWB, and SWB scores. Survivors with a history of chemotherapy had smaller improvements in FACT-General, FACT-Breast, PWB, SWB, TOI, and AC scores, all p < 0.05.

CONCLUSION

These findings indicate that being < 2 years post-diagnosis, single, and prior chemotherapy may limit MVPA and QOL responses to a PA intervention. Further studies are needed to determine if and/or what additional PA supports and resources these subgroups of BCS might find beneficial and effective.

TRIAL REGISTRATION

ClinicalTrials.gov number: NCT00929617.

Comparing wire-mesh sensor with neutron radiography for measurement of liquid fraction in foam

The liquid fraction of foam is an important quantity in engineering process control and essential to interpret foam rheology. Established measurement tools for the liquid fraction of foam, such as optical measurement or radiography techniques as well as weighing the foam, are mostly laboratory-based, whereas conductivity-based measurements are limited to the global measurement without detailed spatial information of liquid fraction. In this work, which combines both types of measurement techniques, the conductivity-based wire-mesh sensor is compared with neutron radiography. We found a linear dependency between the liquid fraction of the foam and the wire-mesh readings with a statistical deviation less than 15%. However, the wire-mesh sensor systematically overestimates the liquid fraction, which we attribute to liquid bridge formation between the wires.

Web-Based Lifestyle Interventions for Survivors of Cancer: Usability Study

BACKGROUND

Internet-based lifestyle programs are increasingly being used to deliver health behavior change interventions to survivors of cancer. However, little is known about website use in this population or its association with healthy lifestyle changes.

OBJECTIVE

The aim of this study is to describe lifestyle intervention website use (log-ins, time on website, and page views) among survivors of cancer and patterns of use by participant characteristics. In addition, associations were explored between website use and changes in healthy lifestyle knowledge and practice.

METHODS

A total of 35 survivors of cancer were recruited between August 2017 and 2018 to participate in a 2-week, single-arm pilot test of the SurvivorSHINE lifestyle intervention website. Knowledge and practices related to healthy diet and physical activity behaviors were measured at baseline and follow-up. Website use (eg, time spent on the website, frequency of log-ins, and page views) were collected from the SurvivorSHINE administrative site during the intervention period. Patterns of use were examined by participants' gender and race. Correlations between website use and changes in healthy lifestyle knowledge, physical activity, diet, and weight were explored. Mann-Whitney U tests were used to compare demographic factors on website use.

RESULTS

Participants logged into the SurvivorSHINE intervention website an average of 3.2 (SD 2) times over the 2-week period and spent a total average of 94 (SD 56) minutes viewing the website during the intervention. Examining website activity, 1905 page views were logged. The User Profile (344 page views) and Home sections (301 page views) were the most frequently visited components. No associations were observed between the frequency of log-ins or the total time on the website, improvements in knowledge related to healthy lifestyles, or changes in body weight or dietary intake. However, the total time on the website was positively correlated with improvements in accelerometer-measured physical activity (r=0.74; P=.02) and self-reported physical activity (r=0.35; P=.04).

CONCLUSIONS

Survivors of cancer demonstrated clear interest in a diet and exercise intervention website, as evidenced by their frequency of log-ins, page views on numerous features, and total viewing time. Moreover, increased website use was correlated with improvements in physical activity.

An Interactive Voice Response System to Increase Physical Activity and Prevent Cancer in the Rural Alabama Black Belt: Design and Usability Study

BACKGROUND

Increased physical activity (PA) levels are associated with reduced risk and improved survival for several cancers; however, most Americans engage in less than the recommended levels of PA. Using interactive voice response (IVR) systems to provide personalized health education and counseling may represent a high-reach, low-cost strategy for addressing physical inactivity and cancer disparities in disproportionately burdened rural regions. However, there has been a paucity of research conducted in this area to date.

OBJECTIVE

The aim of this study is to design, develop, and test the usability of an IVR system aimed at increasing PA levels in the rural Alabama Black Belt.

METHODS

A pilot version of the IVR system was used to assess initial feasibility and acceptability. Detailed exit interviews were conducted to elicit participant feedback, which helped inform the development of a substantially upgraded in-house IVR system. This refined IVR system was then subjected to a sequential explanatory mixed methods evaluation. Participating rural county coordinators and research staff (N=10) tested the usability of the IVR system features for 2 weeks and then completed the System Usability Scale and qualitative semistructured interviews.

RESULTS

The study sample comprised mostly African American people, women, rural county coordinators, and research staff (N=10). Participants rated the IVR system with a mean score of 81 (SD 5) on the System Usability Scale, implying excellent usability. In total, 5 overarching themes emerged from the qualitative interviews: likes or dislikes of the intervention, barriers to or facilitators of PA, technical difficulties, quality of calls, and suggestions for intervention improvement. Message framing on step feedback, call completion incentives, and incremental goal-setting challenges were areas identified for improvement. The positive areas highlighted in the interviews included the personalized call schedules, flexibility to call in or receive a call, ability to make up for missed calls, narration, and PA tips.

CONCLUSIONS

The usability testing and feedback received from the rural county coordinators and research staff helped inform a final round of refinement to the IVR system before use in a large randomized controlled trial. This study stresses the importance of usability testing of all digital health interventions and the benefits it can offer to the intervention.

Fatty acid composition of adipose tissue at term indicates deficiency of arachidonic and docosahexaenoic acid and excessive linoleic acid supply in preterm infants

BACKGROUND

Arachidonic (ARA) and docosahexaenoic acid (DHA) are constitutive to membrane phospholipids, and essential for brain and overall development. ARA/DHA pools in term infants (TI) are built during the third trimester, stored as adipose tissue triglycerides and predominantly distributed via plasma phosphatidylcholine (PC). In preterm infants (PTI), placental ARA/DHA supply is replaced by linoleic-acid (LA)-enriched nutrition. This study aimed to investigate the impact of PTI nutrition, compared to placental supply, on fatty acid composition in adipose tissue and blood.

METHODS

Prospective observational study (4/2017-3/2019) in 12 PTI and 3 PTI with enterostomy (PTI/E) (gestational age (GA) < 32 weeks) with surgical intervention at term (± 6 weeks) and 14 TI (GA ≥ 34 weeks, surgical intervention < 2 weeks postnatally). PTI/E were analyzed descriptively only. PC and triglyceride fatty acids were analyzed with tandem mass spectrometry and gas chromatography, respectively. Results were compared between TI and PTI with Wilcoxon Test and shown as median [25th percentile-75th percentile] mol%.

RESULTS

PTI had less ARA in adipose tissue TG (0.77[0.67-0.87]% vs. 1.04[0.95-1.14]%, p = 0.0003) and plasma PC (20.7[18.7-22.8]% vs. 28.3[22.7-33.5]%, p = 0.011) than TI. PTI also had less DHA in adipose tissue TG (0.6[0.4-0.8]% vs. 1.1[0.8-1.4]%, p = 0.006) and plasma PC (6.4[5.6-7.1]% vs. 8.4[7.8-13.1]%, p = 0.002). LA was increased in PTI's adipose tissue TG (10.0[8.8-12.3]% vs. 3.0[2.5-3.6]%, p < 0.0001) and plasma PC (48.4[44.6-49.6]% vs. 30.6[24.9-35.6]%, p = 0.0002). Similar differences were observed in erythrocyte PC.

CONCLUSION

In PTI, LA is increased and ARA/DHA decreased in adipose tissue, plasma and erythrocyte lipids as proxies for other tissues, likely caused by PTI nutrition. This may contribute to impaired PTI development.

Epigenetic activation of O-linked β-N-acetylglucosamine transferase overrides the differentiation blockage in acute leukemia

Background

Overriding the differentiation blockage in acute myeloid leukemia (AML) is the most successful mode-of-action in leukemia therapy – now curing the vast majority of patients with acute promyelocytic leukemia (APL) using all-trans retinoic acid (ATRA)-based regimens. Similar approaches in other leukemia subtypes, such as IDH1/2-mutated AML, are under active investigation. We herein present successful release of the differentiation blockage upon treatment with the natural (−)-Δ⁹-Tetrahydrocannabinol isomer dronabinol in vitro and in vivo.

Methods

Cellular maturation and differentiation were followed in two patients employing whole genome methylation profiling, proteome analyses, NGS deep sequencing and multispectral imaging flow cytometry. For functional studies lentiviral OGT knock-down in vitro and ex vivo cell models were created to evaluate proliferative, apoptotic and differentiating effects of OGT in acute leukemia.

Findings

In here, we provide molecular evidence that dronbinol is capable to override the differentiation blockage of acute leukemia blasts at the state of the leukemia-initiating clone. We further identify the O-linked β-N-acetyl glucosamine (O-GlcNAc) transferase (OGT) to be crucial in this process. OGT is a master regulator enzyme adding O-GlcNAc to serine or threonine residues in a multitude of target proteins. Aberrant O-GlcNAc modification is implicated in pathologies of metabolic, neurodegenerative and autoimme diseases as well as cancers. We provide evidence that dronabinol induces transcription of OGT via epigenetic hypomethylation of the transcription start site (TSS). A lentiviral OGT-knock out approach proves the central role of OGT exerting antileukemic efficacy via a dual-mechanism of action: High concentrations of dronabinol result in induction of apoptosis, whereas lower concentrations drive cellular maturation. Most intriguingly, overriding of the differentiation blockage of acute leukemia blasts is validated in vivo following two patients treated with dronabinol.

Interpretation

In conclusion, we provide evidence for overcoming the differentiation blockage in acute leukemia in subentities beyond promyelocytic and IDH1/2-mutated leukemia and thereby identify O-GlcNAcylation as a novel (drugable) field for future leukemia research.

Funding

Unrestricted grant support by the IZKF Program of the Medical Faculty Tübingen (MMS) and Brigitte Schlieben-Lange Program as well as the Margarete von Wrangell Program of the Ministry of Science, Research and the Arts, Baden-Württemberg, Germany (KKS) and Athene Program of the excellence initiative University of Tübingen (KKS).

The protective effect of human renal sinus fat on glomerular cells is reversed by the hepatokine fetuin-A

Renal sinus fat (RSF) is a perivascular fat compartment located around renal arteries. In this in vitro and in vivo study we hypothesized that the hepatokine fetuin-A may impair renal function in non alcoholic fatty liver disease (NAFLD) by altering inflammatory signalling in RSF. To study effects of the crosstalk between fetuin-A, RSF and kidney, human renal sinus fat cells (RSFC) were isolated and cocultured with human endothelial cells (EC) or podocytes (PO). RSFC caused downregulation of proinflammatory and upregulation of regenerative factors in cocultured EC and PO, indicating a protective influence of RFSC. However, fetuin-A inverted these benign effects of RSFC from an anti- to a proinflammatory status. RSF was quantified by magnetic resonance imaging and liver fat content by ¹H-MR spectroscopy in 449 individuals at risk for type 2 diabetes. Impaired renal function was determined via urinary albumin/creatinine-ratio (uACR). RSF did not correlate with uACR in subjects without NAFLD (n = 212, p = 0.94), but correlated positively in subjects with NAFLD (n = 105, p = 0.0005). Estimated glomerular filtration rate (eGRF) was inversely correlated with RSF, suggesting lower eGFR for subjects with higher RSF (r = 0.24, p < 0.0001). In conclusion, our data suggest that in the presence of NAFLD elevated fetuin-A levels may impair renal function by RSF-induced proinflammatory signalling in glomerular cells.

Medium-chain fatty acids modulate myocardial function via a cardiac odorant receptor

Several studies have demonstrated the expression of odorant receptors (OR) in various human tissues and their involvement in different physiological and pathophysiological processes. However, the functional role of ORs in the human heart is still unclear. Here, we firstly report the functional characterization of an OR in the human heart. Initial next-generation sequencing analysis revealed the OR expression pattern in the adult and fetal human heart and identified the fatty acid-sensing OR51E1 as the most highly expressed OR in both cardiac development stages. An extensive characterization of the OR51E1 ligand profile by luciferase reporter gene activation assay identified 2-ethylhexanoic acid as a receptor antagonist and various structurally related fatty acids as novel OR51E1 ligands, some of which were detected at receptor-activating concentrations in plasma and epicardial adipose tissue. Functional investigation of the endogenous receptor was carried out by Ca²⁺ imaging of human stem cell-derived cardiomyocytes. Application of OR51E1 ligands induced negative chronotropic effects that depended on activation of the OR. OR51E1 activation also provoked a negative inotropic action in cardiac trabeculae and slice preparations of human explanted ventricles. These findings indicate that OR51E1 may play a role as metabolic regulator of cardiac function.

A microwave resonator integrated on a polymer microfluidic chip

We describe a novel stacked split-ring type microwave (MW) resonator that is integrated into a 10mm by 10mm sized microfluidic chip. A straightforward and scalable batch fabrication process renders the chip suitable for single-use applications. The resonator volume can be conveniently loaded with liquid sample via microfluidic channels patterned into the mid layer of the chip. The proposed MW resonator offers an alternative solution for compact in-field measurements, such as low-field magnetic resonance (MR) experiments requiring convenient sample exchange. A microstrip line was used to inductively couple MWs into the resonator. We characterised the proposed resonator topology by electromagnetic (EM) field simulations, a field perturbation method, as well as by return loss measurements. Electron paramagnetic resonance (EPR) spectra at X-band frequencies were recorded, revealing an electron-spin sensitivity of 3.7·10(11)spins·Hz(-1/2)G(-1) for a single EPR transition. Preliminary time-resolved EPR experiments on light-induced triplet states in pentacene were performed to estimate the MW conversion efficiency of the resonator.

Morphological aspects of basement-membranes and their receptors in benign and malignant neoplasms (review)

We review the current knowledge on alterations of the major basement membrane (BM) components and their cellular integrin receptors in benign and malignant tumors of epithelial and mesenchymal origin. While benign tumors usually exhibit a continous BM, recent analyses provide evidence that invasive growth of carcinomas coincides with (a) a loss in a proper BM, (b) changes in the type of integrin receptor expression and (c) the retained ability of certain tumor cells to synthesize matrix components. This latter aspect has been regarded as a potentially beneficial 'host' mechanism against invasive growth. This assumption is strongly supported by the finding of a positive correlation between the extent of BM loss and both a lesser degree of tumor differentiation and a worse prognosis of tumor growth. The resulting concept indicates that in carcinomas an imbalance in the cell-matrix interaction is the leading element in invasive growth. In mesenchymal tumors a somewhat different role of the BM can be observed. Thus, the qualitative and quantitative expression of major BM components in benign mesenchymal tumors closely relates to the BM pattern of normal tissues providing a histogenetically oriented classification of benign mesenchymal tumors. Most well-differentiated sarcomas retain a BM pattern close to that of the histogenetically related tissue, although in poorly differentiated sarcomas no such attribution to a histogenetic orientation of the tumor cells can be found.

Exercise-induced albuminuria is associated with perivascular renal sinus fat in individuals at increased risk of type 2 diabetes

AIMS/HYPOTHESIS

Microalbuminuria represents an established surrogate marker of early diabetic nephropathy and glomerular microangiopathy. Increasing evidence is emerging of a role of perivascular adipose tissue (PVAT) as an important link between obesity, insulin resistance and both macro- and microangiopathy. It is not known whether perivascular renal sinus fat (RSF) has an impact on microalbuminuria in the prediabetic stage. We investigated whether RSF quantified by MRI is associated with microalbuminuria before or after exercise.

METHODS

Non-diabetic individuals at increased risk of type 2 diabetes were recruited into the Tübingen Lifestyle Intervention Program (TULIP); 146 participants took part in the analysis. RSF was measured in axial MRI sections at the level of the renal artery. Urine was collected before and after exercise stress testing.

RESULTS

Participants (age 47 ± 12 years; mean ± SD) reached a mean exercise load of 176 ± 49 W, with a mean arterial peak pressure (MAPP) of 112 ± 14 mmHg. After adjusting for sex, age, visceral adipose tissue (VAT) and MAPP during exercise, RSF was significantly associated with postexercise albumin/creatinine ratio (ACR; p = 0.006). No association between RSF and baseline BP could be observed after adjusting for confounders (p = 0.26), and there was no association between RSF and baseline ACR either (p = 0.2).

CONCLUSIONS

RSF is associated with exercise-induced albuminuria independently of sex, age, VAT and MAPP in a non-diabetic cohort at diabetic risk. We conclude that PVAT in the renal sinus may play a role in the pathogenesis of microalbuminuria.

High cerebral insulin sensitivity is associated with loss of body fat during lifestyle intervention

AIMS/HYPOTHESIS

Loss of weight and body fat are major targets in lifestyle interventions to prevent diabetes. In the brain, insulin modulates eating behaviour and weight control, resulting in a negative energy balance. This study aimed to test whether cerebral insulin sensitivity facilitates reduction of body weight and body fat by lifestyle intervention in humans.

METHODS

The study was performed as an additional arm of the TUebingen Lifestyle Intervention Program (TULIP). In 28 non-diabetic individuals (14 female/14 male; mean ± SE age 42 ± 2 years; mean ± SE BMI 29.9 ± 0.8 kg/m²), we measured cerebrocortical insulin sensitivity by using magnetoencephalography before lifestyle intervention. Total and visceral fat were measured by using MRI at baseline and after 9 months and 2 years of lifestyle intervention.

RESULTS

Insulin-stimulated cerebrocortical theta activity at baseline correlated with a reduction in total adipose tissue (r = -0.59, p = 0.014) and visceral adipose tissue (r = -0.76, p = 0.001) after 9 months of lifestyle intervention, accompanied by a statistical trend for reduction in body weight change (r = -0.37, p = 0.069). Similar results were obtained after 2 years.

CONCLUSIONS/INTERPRETATION

Our results suggest that high insulin sensitivity of the human brain facilitates loss of body weight and body fat during lifestyle intervention.

Association of changes in body mass index during earlier adulthood and later adulthood with circulating obesity biomarker concentrations in middle-aged men and women

AIMS/HYPOTHESIS

The objective of our study was to investigate whether changes in BMI during earlier adulthood are more strongly associated with levels of circulating obesity biomarkers in middle age than are BMI changes during later adulthood.

METHODS

The study included 1,612 participants from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study. The associations of BMI changes based on recalled BMI for the age ranges 25-40 years (earlier adulthood) and 40-55 years (later adulthood) with later biomarker levels were compared using a linear model, adjusted for BMI at age 25 years and conventional risk factors.

RESULTS

BMI changes during both time periods as well as BMI at age 25 years were significantly associated with circulating levels of adiponectin, γ-glutamyltransferase (GGT), alanine aminotransferase (ALT), high-sensitivity C-reactive protein (hs-CRP) and HDL-cholesterol (HDL-C) in both sexes, and of HbA(1c) in women. However, BMI gain for the age range 25-40 years was significantly more strongly associated with unfavourable levels of adiponectin, hs-CRP, HDL-C and HbA(1c) in men and women, and of GGT and ALT in men (p difference <0.05) than BMI gain for the age range 40-55 years. The percentage change in biomarker levels per unit gain in BMI for the age range 25-40 years ranged from 0.81% (HbA(1c)) to 9.80% (hs-CRP) in men, and from 0.75% (HbA(1c)) to 14.7% (hs-CRP) in women, whereas for the age range 40-55 years, values ranged from -0.15% to 4.82% in men and from 0.25% to 7.06% in women.

CONCLUSIONS/INTERPRETATION

The results support the hypothesis that an increase in BMI in earlier adulthood is more strongly associated with unfavourable circulating levels of obesity biomarkers later in life than is an increase in BMI in later adulthood.

Diagnostic value of hemoglobin A1c for type 2 diabetes mellitus in a population at risk

OBJECTIVE

Because the American Diabetes Association has recently included HbA1c as the primary diagnostic test for the detection of diabetes mellitus (HbA1c ≥6.5%) we investigated its use as screening parameter for diabetes in a cohort at increased risk for the disease.

RESEARCH DESIGN AND METHODS

During the last 10 years 2 036 Caucasians at risk to develop type 2 diabetes but not having this diagnosis yet, consecutively underwent a 75 g oral glucose tolerance test (OGTT). HbA1c was determined with the HPLC method (Tosoh A1c 2.2), external and internal quality controls were well within the allowed ranges.

RESULTS

The oral glucose tolerance test classified 1 523 individuals as normal glucose tolerant (NGT), 387 as impaired glucose tolerant (IGT) or having impaired fasting glycemia (IFG) and 126 as diabetic. The 6.5% cut-off value of HbA1c classified 47% of the diabetic individuals correctly. Of the remaining 53% diabetic individuals (HbA1c <6.5%) 35% had increased fasting glucose levels, while 65% were only diagnosed by their increased 2 h glucose values.

CONCLUSION

A cut-off value of 6.5% HbA1c classifies diabetic subjects with a specificity of 98.7%. However, the sensitivity of 46.8% is low, indicating that more than half of diabetic subjects are missed when using this test. The present data shows that the use of HbA1c as a the primary diagnostic test will reduce diabetes prevalence. Furthermore, it suggests, that HbA1c and OGTT measurements cannot simply be exchanged, but most probably detect and define different categories of diabetes, i. e., categories with different risk of cardiovascular disease.