Urine specific gravity as an indicator of dehydration in Olympic combat sport athletes; considerations for research and practice

Urine specific gravity (U_SG) is the most commonly reported biochemical marker used in research and applied settings to detect fluid deficits in athletes, including those participating in combat sports. Despite the popularity of its use, there has been a growing debate regarding the diagnostic accuracy and the applicability of U_SG in characterizing whole-body fluid status and fluctuations. Moreover, recent investigations report universally high prevalence of hypohydration (～90%) via U_SG assessment in combat sport athletes, often in spite of stable body-mass. Given the widespread use in both research and practice, and its use in a regulatory sense as a ‘hydration test’ in combat sports as a means to detect dehydration at the time of weigh-in; understanding the limitations and applicability of U_SG assessment is of paramount importance. Inconsistencies in findings of U_SG readings, possibly as a consequence of diverse methodological research approaches and/or overlooked confounding factors, preclude a conclusive position stand within current combat sports research and practice. Thus the primary aim of this paper is to critically review the literature regarding U_SG assessment of hydration status in combat sports research and practice. When taken on balance, the existing literature suggests: the use of laboratory derived benchmarks in applied settings, inconsistent sampling methodologies, the incomplete picture of how various confounding factors affect end-point readings, and the still poorly understood potential of renal adaptation to dehydration in combat athletes; make the utility of hydration assessment via U_SG measurement quite problematic, particularly when diet and training is not controlled.     

Efficient video-on-demand services over mobile datacast channels

[1]Engebretsen,L.,Sudan,M.,2002.Harmonic Broadcasting is Bandwidth-Optimal Assuming Constant Bit Rate.Proc.Annual ACM-SIAM Symposium on Discrete Algorithms.San Francisco,CA,USA. [2]ETSI,2005.IP Datacast over DVB-H:Content Delivery Protocols.ETSI Standard,Draft,V0.0.9. [3]Horn,G.B.,Knudsgaard,P.,Lassen,S.B.,Luby,M.,Rasmussen,J.E.,2001.A scalable and reliable paradigm for media on demand.IEEE Computer,34(9):40-45. [4]Hu,A.,2001.Video-on-Demand Broadcasting Protocols:A Comprehensive Study.Proc.IEEE Infocom.Anchorage,Alaska. [5]Huang,C.,Janakiraman,R.,Xu,L.,2004.Loss-Resilient Media Streaming Using Priority Encoding.Proc.ACM International Conference on Multimedia (MM‘04).New York,USA. [6]Jenka(c),H.,Stockhammer,T.,2005.Asynchronous Media Streaming over Wireless Broadcast Channels.Proc.of International Conference on Multimedia and Expo (ICME).Amsterdam,The Netherlands. [7]Luby,M.,Gemmel,J.,Vicisano,L.,Rizzo,L.,Handley,M.,Crowcroft,J.,2002a.Asynchronous Layered Coding (ALC) Protocol Instantiation.RFC 3450,IETF. [8]Luby,M.,Gemmel,J.,Vicisano,L.,Rizzo,L.,Handley,M.,Crowcroft,J.,2002b.Layered Coding Transport (LCT)Building Block.RFC 3451,IETF. [9]Luby,M.,Vicisano,L.,Gemmel,J.,Handley,M.,Crowcroft,J.,2002c.Forward Error Correction (FEC) Building Block.RFC 3452,IETF. [10]Luby,M.,Watson,M.,Gasiba,T.,Stockhammer,T.,Xu,W.,2006.Raptor Codes for Reliable Download Delivery in Wireless Broadcast Systems.Proc.Consumer and Communications Networking Conference (CCNC).Las Vegas,NV,USA. [11]Paila,T.,Luby,M.,Lehtonen,R.,Roca,V.,Walsh,R.,2004.FLUTE-File Delivery over Unidirectional Transport.RFC 3926,IETF. [12]Peltotalo,J.,Peltotalo,S.,Harju,J.,2005.Analysis of the FLUTE Data Carousel.Proc.10th EUNICE Open European Summer School.Colmenarejo,Spain. [13]Shokrollahi,A.,2003.Raptor Codes.Tech.Rep.DR2003-06-001,Digital Fountain. [14]TM-CBMS1361,2005.Proposal for Simulations for Evaluation of Application Layer FEC for File Delivery. [15]Xu,L.,2001.Efficient and Scalable on-Demand Data Streaming Using UEP Codes.Proc.ACM International Conference on Multimedia (MM‘01).Ottawa,Ontario,Canada.     

Haemoglobin A1c-based screening for prediabetes and diabetes mellitus: a multi-center study in Croatian adult population

IntroductionBased on the hypothesis that there is a substantial rate of adults with prediabetes and undiagnosed diabetes mellitus (DM), our aim was to perform haemoglobin A1c (HbA_1c)-based screening in a cohort of Croatian adults and estimate the prevalence of prediabetes and undiagnosed DM according to American Diabetes Association criteria.Materials and methodsThis multi-center, cross-sectional study performed in six Croatian hospitals included 5527 patients aged 40 to 70 years admitted to the Emergency Department or undergoing a primary care check-up. Haemoglobin A1c was measured from leftover whole blood samples using the enzymatic method on either Alinity c or Architect c-series analyser (Abbott Laboratories, Chicago, USA). Haemoglobin A1c between 39-47 mmol/mol was classified as prediabetes, while ≥ 48 mmol/mol as undiagnosed DM.ResultsAfter exclusion of 435 patients with known DM, the final cohort included 5092 patients (median age 57; 56% males). A total of 882 (17.3%) patients had HbA_1c values between 39 and 47 mmol/mol. There were 214 (4.2%) patients with HbA_1c ≥ 48 mmol/mol. Prediabetes prevalence ranged from 14.2% to 20.5%, while undiagnosed DM from 3.3% to 7.3%, with statistically significant differences among settings (P < 0.001). Age-stratified analysis showed that prediabetes and undiagnosed DM prevalence increase with age (P < 0.001), being 25.4% and 5.8%, respectively, in patients aged 60 to 70 years.ConclusionUnderlying impairment of glucose metabolism was identified in about one in five adults, with significant number of patients with already overt DM. These results should serve as a starting point for further steps directed towards promotion of preventive measures for DM in Croatia.