Vitamin D and the Athlete: Current Perspectives and New Challenges

The last decade has seen a dramatic increase in general interest in and research into vitamin D, with many athletes now taking vitamin D supplements as part of their everyday dietary regimen. The most recognized role of vitamin D is its regulation of calcium homeostasis; there is a strong relationship between vitamin D and bone health in non-athletic individuals. In contrast, data have consistently failed to demonstrate any relationship between serum 25[OH]D and bone health, which may in part be due to the osteogenic stimulus of exercise. Vitamin D may interact with extra-skeletal tissues such as muscle and the immune system to modulate recovery from damaging exercise and infection risk. Given that many athletes now engage in supplementation, often consuming extreme doses of vitamin D, it is important to assess whether excessive vitamin D can be detrimental to health. It has been argued that toxic effects only occur when serum 25[OH] D concentrations are greater than 180 nmol·l −1 , but data from our laboratory have suggested high-dose supplementation could be problematic. Finally, there is a paradoxical relationship between serum 25[OH]D concentration, ethnicity, and markers of bone health: Black athletes often present with low serum 25[OH] D without physiological consequences. One explanation for this could be genetic differences in vitamin D binding protein due to ethnicity, resulting in greater concentrations of bioavailable (or free) vitamin D in some ethnic groups. In the absence of any pathology, screening may be unnecessary and could result in incorrect supplementation. Data must now be re-examined, taking into consideration bioavailable or “free” vitamin D in ethnically diverse groups to enable new thresholds and target concentrations to be established; perhaps, for now, it is time to “set vitamin D free”. © 2018 The Author(s

Why don't serum vitamin D concentrations associate with BMD by DXA? A case of being 'bound' to the wrong assay? Implications for vitamin D screening.

BACKGROUND: The association between bone mineral density (BMD) and serum25-hydroxyvitamin D (25(OH)D) concentration is weak, particularly in certain races (eg, BlackAfrican vs Caucasian) and in athletic populations. We aimed to examine if bioavailable vitamin D rather than serum 25(OH)D was related to markers of bone health within a racially diverse athletic population. METHODS: In 604 male athletes (Arab (n=327), Asian (n=48), Black(n=108), Caucasian (n=53)and Hispanic (n=68)), we measured total 25(OH)D, vitamin D-binding protein and BMD by DXA. Bioavailable vitamin D was calculated using the free hormone hypothesis. RESULTS: From 604 athletes, 21.5% (n=130) demonstrated severe 25(OH)D deficiency, 37.1% (n=224) deficiency, 26% (n=157) insufficiency and 15.4% (n=93) sufficiency. Serum 25(OH)D concentrations were not associated with BMD at any site. After adjusting for age and race, bioavailable vitamin D was associated with BMD (spine, neck and hip). Mean serum vitamin D binding protein concentrations were not associated with 25(OH)D concentrations (p=0.392). CONCLUSION: Regardless of age or race, bioavailable vitamin D and not serum 25(OH)D was associated with BMD in a racially diverse athletic population. If vitamin D screening is warranted, clinicians should use appropriate assays to calculate vitamin D binding protein and bioavailable vitamin D levels concentrations than serum 25(OH)D. In turn, prophylactic vitamin D supplementation to 'correct' insufficient athletes should not be based on serum 25(OH)D measures

Results of soy-based meal replacement formula on weight, anthropometry, serum lipids & blood pressure during a 40-week clinical weight loss trial

BACKGROUND: To evaluate the intermediate-term health outcomes associated with a soy-based meal replacement, and to compare the weight loss efficacy of two distinct patterns of caloric restriction. METHODS: Ninety overweight/obese (28 < BMI ≤ 41 kg/m(2)) adults received a single session of dietary counseling and were randomized to either 12 weeks at 1200 kcal/day, 16 weeks at 1500 kcal/d and 12 weeks at 1800 kcal/d (i.e., the 12/15/18 diet group), or 28 weeks at 1500 kcal/d and 12 weeks at 1800 kcal/d (i.e., the 15/18 diet group). Weight, body fat, waist circumference, blood pressure and serum lipid concentrations were measured at 4-week intervals throughout the 40-week trial. RESULTS: Subjects in both treatments showed statistically significant improvements in outcomes. A regression model for weight change suggests that subjects with larger baseline weights tended to lose more weight and subjects in the 12/15/18 group tended to experience, on average, an additional 0.9 kg of weight loss compared with subjects in the 15/18 group. CONCLUSION: Both treatments using the soy-based meal replacement program were associated with significant and comparable weight loss and improvements on selected health variables

Exercise therapy in adults with serious mental illness: a systematic review and meta-analysis

Background: Individuals with serious mental illness are at a higher risk of physical ill health. Mortality rates are at least twice those of the general population with higher levels of cardiovascular disease, metabolic disease, diabetes, and respiratory illness. Although genetics may have a role in the physical health problems of these patients, lifestyle and environmental factors such as levels of smoking, obesity, poor diet, and low levels of physical activity also play a prominent part.&lt;p&gt;&lt;/p&gt; Objective: To conduct a systematic review and meta-analysis of randomised controlled trials comparing the effect of exercise interventions on individuals with serious mental illness.&lt;p&gt;&lt;/p&gt; Methods: Searches were made in Ovid MEDLINE, Embase, CINAHL, PsycINFO, Biological Abstracts on Ovid, and The Cochrane Library (January 2009, repeated January 2013) through to February 2013.&lt;p&gt;&lt;/p&gt; Results: Eight RCTs were identified in the systematic search. Six compared exercise versus usual care. One study assessed the effect of a cycling programme versus muscle strengthening and toning exercises. The final study compared the effect of adding specific exercise advice and motivational skills to a simple walking programme. Exercise programmes were noted by their heterogeneity in terms of the type of exercise intervention, setting, and outcome measures. The review found that exercise improved levels of exercise activity (n=13, standard mean difference [SMD] 1.81, CI 0.44 to 3.18, p = 0.01). No beneficial effect was found on negative (n = 84, SMD = -0.54, CI -1.79 to 0.71, p = 0.40) or positive symptoms of schizophrenia (n = 84, SMD = -1.66, CI -3.78 to 0.45, p = 0.12). No change was found on body mass index compared with usual care (n= 151, SMD = -0.24, CI -0.56 to 0.08, p = 0.14), or body weight (n = 77, SMD = 0.13, CI -0.32 to 0.58, p = 0.57). No beneficial effect was found on anxiety and depressive symptoms (n = 94, SMD = -0.26, CI -0.91 to 0.39, p = 0.43), or quality of life in respect of physical and mental domains. One RCT measured the effect of exercise on exercise intensity, attendance, and persistence at a programme. No significant effect was found on these measures.&lt;p&gt;&lt;/p&gt; Conclusions: This systematic review showed that exercise therapies can lead to a modest increase in levels of exercise activity but overall there was no noticeable change for symptoms of mental health, body mass index, and body weight.&lt;p&gt;&lt;/p&gt

Evaluating Statistical Methods Using Plasmode Data Sets in the Age of Massive Public Databases: An Illustration Using False Discovery Rates

Plasmode is a term coined several years ago to describe data sets that are derived from real data but for which some truth is known. Omic techniques, most especially microarray and genomewide association studies, have catalyzed a new zeitgeist of data sharing that is making data and data sets publicly available on an unprecedented scale. Coupling such data resources with a science of plasmode use would allow statistical methodologists to vet proposed techniques empirically (as opposed to only theoretically) and with data that are by definition realistic and representative. We illustrate the technique of empirical statistics by consideration of a common task when analyzing high dimensional data: the simultaneous testing of hundreds or thousands of hypotheses to determine which, if any, show statistical significance warranting follow-on research. The now-common practice of multiple testing in high dimensional experiment (HDE) settings has generated new methods for detecting statistically significant results. Although such methods have heretofore been subject to comparative performance analysis using simulated data, simulating data that realistically reflect data from an actual HDE remains a challenge. We describe a simulation procedure using actual data from an HDE where some truth regarding parameters of interest is known. We use the procedure to compare estimates for the proportion of true null hypotheses, the false discovery rate (FDR), and a local version of FDR obtained from 15 different statistical methods

Missing Data in Randomized Clinical Trials for Weight Loss: Scope of the Problem, State of the Field, and Performance of Statistical Methods

BACKGROUND: Dropouts and missing data are nearly-ubiquitous in obesity randomized controlled trails, threatening validity and generalizability of conclusions. Herein, we meta-analytically evaluate the extent of missing data, the frequency with which various analytic methods are employed to accommodate dropouts, and the performance of multiple statistical methods. METHODOLOGY/PRINCIPAL FINDINGS: We searched PubMed and Cochrane databases (2000-2006) for articles published in English and manually searched bibliographic references. Articles of pharmaceutical randomized controlled trials with weight loss or weight gain prevention as major endpoints were included. Two authors independently reviewed each publication for inclusion. 121 articles met the inclusion criteria. Two authors independently extracted treatment, sample size, drop-out rates, study duration, and statistical method used to handle missing data from all articles and resolved disagreements by consensus. In the meta-analysis, drop-out rates were substantial with the survival (non-dropout) rates being approximated by an exponential decay curve (e(-lambdat)) where lambda was estimated to be .0088 (95% bootstrap confidence interval: .0076 to .0100) and t represents time in weeks. The estimated drop-out rate at 1 year was 37%. Most studies used last observation carried forward as the primary analytic method to handle missing data. We also obtained 12 raw obesity randomized controlled trial datasets for empirical analyses. Analyses of raw randomized controlled trial data suggested that both mixed models and multiple imputation performed well, but that multiple imputation may be more robust when missing data are extensive. CONCLUSION/SIGNIFICANCE: Our analysis offers an equation for predictions of dropout rates useful for future study planning. Our raw data analyses suggests that multiple imputation is better than other methods for handling missing data in obesity randomized controlled trials, followed closely by mixed models. We suggest these methods supplant last observation carried forward as the primary method of analysis

Controls on gut phosphatisation : the trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah)

Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods--typically the most diverse fossilised organisms in Cambrian ecosystems--where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerstätte (Utah). Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous) in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace

Evolutionary Determinants of Genetic Variation in Susceptibility to Infectious Diseases in Humans

Although genetic variation among humans in their susceptibility to infectious diseases has long been appreciated, little focus has been devoted to identifying patterns in levels of variation in susceptibility to different diseases. Levels of genetic variation in susceptibility associated with 40 human infectious diseases were assessed by a survey of studies on both pedigree-based quantitative variation, as well as studies on different classes of marker alleles. These estimates were correlated with pathogen traits, epidemiological characteristics, and effectiveness of the human immune response. The strongest predictors of levels of genetic variation in susceptibility were disease characteristics negatively associated with immune effectiveness. High levels of genetic variation were associated with diseases with long infectious periods and for which vaccine development attempts have been unsuccessful. These findings are consistent with predictions based on theoretical models incorporating fitness costs associated with the different types of resistance mechanisms. An appreciation of these observed patterns will be a valuable tool in directing future research given that genetic variation in disease susceptibility has large implications for vaccine development and epidemiology

Trends of increase in western medical services in traditional medicine hospitals in china

Background: Compare changes in types of hospital service revenues between traditional Chinese medicine (TCM) hospitals and Western-medicine based general hospitals. Methods: 97 TCM hospitals and 103 general hospitals were surveyed in years of 2000 and 2004. Six types of medical service revenue between the two types of hospitals were compared overtime. The national statistics from 1999 to 2008 were also used as complementary evidence. Results: For TCM hospitals, the percentage of service revenue from Western medicine increased from 44.3% to 47.4% while the percentage of service revenue from TCM declined from 26.4% to 18.8% from 1999 to 2004. Percentages of revenue from laboratory tests and surgical procedures for both types of hospitals increased and the discrepancy between the two types of hospitals was narrowed from 1999 to 2004. For TCM hospitals, revenues from laboratory tests increased from 3.64% to 5.06% and revenues from surgical procedures increased from 3.44% to 7.02%. General hospitals\u27 TCM drug revenue in outpatient care declined insignificantly from 5.26% to 3.87%, while the decline for the TCM hospitals was significant from 19.73% to 13.77%. The national statistics from 1999 to 2008 showed similar trends that the percentage of revenue from Western medicine for TCM hospitals increased from 59.6% in 1999 to 62.2% in 2003 and 66.1% in 2008 while the percentage of revenue from TCM for TCM hospitals decreased from 18.0% in 1999, 15.4% in 2003, and 13.7% in 2008. Conclusion: Western medicine has become a vital revenue source for TCM hospitals in the current Chinese health care environment where government subsidies to health care facilities have significantly declined. Policies need to encourage TCM hospitals to identify their own special and effective services, improve public perception, increase demand, strengthen financial sources, and ultimately make contributions to preserving one of the national treasures

Different degrees of malnutrition and immunological alterations according to the aetiology of cirrhosis: a prospective and sequential study

OBJECTIVES: In this work we investigated how immunological dysfunction and malnutrition interact in alcoholic and viral aetiologies of cirrhosis. METHODS: To investigate the matter, 77 cirrhotic patients divided in three aetiologies [Alcohol, HCV and Alcohol + HCV) and 32 controls were prospectivelly and sequentially studied. Parameters of humoral immunity (Components 3 and 4 of seric complement and immunoglobulins A M, G and E) and of cellular immunity (total leukocytes and lymphocytes in peripheral blood, T lymphocytes subpopulations, CD4+ and CD8+, CD4+/CD8+ ratio and intradermic tests of delayed hypersensitivity), as well as nutrititional parameters: anthropometric measures, serum albumin and transferrin were evaluated. RESULTS: Multiple statistical comparisons showed that IgM was higher in HCV group; IgG was significantly elevated in both HCV and Alcohol + HCV, whereas for the Alcohol group, IgE was found at higher titles. The analysis of T- lymphocytes subpopulations showed no aetiologic differences, but intradermic tests of delayed hypersensitivity did show greater frequency of anergy in the Alcohol group. For anthropometric parameters, the Alcohol +HCV group displayed the lowest triceps skinfold whereas creatinine – height index evaluation was more preserved in the HCV group. Body mass index, arm muscle area and arm fat area showed that differently from alcohol group, the HCV group was similar to control. CONCLUSION: Significant differences were found among the main aetiologies of cirrhosis concerning immunological alterations and nutritional status: better nutrition and worse immunology for HCV and vice-versa for alcohol