[Effects of the COVID-19 lockdown on physical performance parameters in professional football]. / Auswirkungen des COVID-19-Lockdowns auf physische Leistungsparameter im professionellen Fußball: Eine narrative Literaturübersicht.

Background: Governmental measures in 2020 to contain the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) brought training and competition in professional soccer to a temporary halt in many countries. As a result of the lockdown, training possibilities were mostly limited to nonspecific home-based training methods. It is unclear whether the lack of sport-specific stimuli led to a reduction in the physical performance of soccer players. Methods: For the narrative review, the PubMed, Google Scholar and BISp-Surf databases were selectively searched for studies examining the effects of the lockdown on physical performance parameters in adult professional soccer players. Results: In this review six prospective longitudinal studies were included. In all studies home-based training was performed during quarantine. Of the studies four compared the performance of the soccer players with data from previous seasons and two studies assessed the performance of players immediately before and after the lockdown period. Discussion: While general strength and endurance performances can be maintained through home-based substitute training programs, the studies indicated that the lack of football-specific stimuli could have an impact on the rapid power and speed performances of soccer players. Progressive loading control especially for speed training should be considered when returning to regular training in order to reduce the risk of injuries.

Functional relevance of genes implicated by obesity genome-wide association study signals for human adipocyte biology.

AIMS/HYPOTHESIS: Genome-wide association studies (GWAS) have identified numerous single-nucleotide polymorphisms associated with obesity, consequently implying a role in adipocyte biology for many closely residing genes. We investigated the functional relevance of such genes in human adipocytes. METHODS: We selected eight genes (BDNF, MAF, MTCH2, NEGR1, NPC1, PTER, SH2B1 and TMEM18) from obesity GWAS and analysed their effect in human adipogenesis using small interfering (si)RNA-mediated knockdown, their regulation by metabolic agents in adipocytes and pre-adipocytes, and gene expression in paired samples of human fat biopsies (68 non-obese, 165 obese) by quantitative real-time PCR. RESULTS: We show a two- to threefold upregulation of MAF, MTCH2 and NEGR1 and a two- to fourfold downregulation of BDNF and PTER during adipogenesis. Knockdown of BDNF (mean ± SEM; 83.8 ± 4.7% of control; p = 0.0002), MTCH2 (72.7 ± 9.5%; p = 0.0006), NEGR1 (70.2 ± 5.7%; p < 0.0001) and TMEM18 (70.8 ± 6.1%; p < 0.0001) significantly inhibited adipocyte maturation, while knockdown of the other proteins had no effect. Insulin slightly induced MAF (1.65-fold; p = 0.0009) and MTCH2 (1.72-fold; p < 0.0001), while it suppressed BDNF (59.6%; p = 0.0009), NEGR1 (58.0%; p = 0.0085) and TMEM18 (69.3%; p = 0.0377) in adipocytes. The synthetic glucocorticoid dexamethasone suppressed MAF (45.7%; p = 0.0022), BDNF (66.6%; p = 0.0012) and TMEM18 (63.5%; p = 0.0181), but induced NEGR1 (3.2-fold; p = 0.0117) expression. Furthermore, MTCH2, NEGR1 and TMEM18 were differentially expressed in subcutaneous and visceral adipose tissue. TMEM18 expression was decreased in the adipose tissue of obese patients, and negatively correlated with anthropometric variables and adipocyte size. CONCLUSIONS/INTERPRETATION: Our results imply a regulatory role for TMEM18, BDNF, MTCH2 and NEGR1 in adipocyte differentiation and biology. In addition, we show a variation of MAF expression during adipogenesis, while NPC1, PTER and SH2B1 were not regulated.

The promoter variant -803 G>A in the RBP4 gene is not associated with BMI, metabolic parameters or blood pressure in Caucasian children.

OBJECTIVE: Studies in adults identified the -803 G>A promoter polymorphism (rs3758539) in the RBP4 gene (RBP4) as a functional variant conferring an increased risk for obesity and type 2 diabetes. METHODS: We genotyped this polymorphism in a cohort of 304 lean and 283 obese children to assess a potential association with early onset obesity and blood pressure and evaluated the effect of this SNP on metabolic parameters in a smaller subset. RESULTS: The allele frequency of -803 G>A was similar in obese compared to lean subjects (0.159 vs. 0.191, P=0.318). We did not detect an association of the variant with adiposity parameters nor with parameters of glucose and lipid metabolism or blood pressure in quantitative analyses. CONCLUSION: Our study revealed that the promoter polymorphism -803 G>A in RBP4 is not associated with BMI, metabolic parameters or blood pressure in Caucasian children.

Leucocytes are a major source of circulating nicotinamide phosphoribosyltransferase (NAMPT)/pre-B cell colony (PBEF)/visfatin linking obesity and inflammation in humans.

AIMS/HYPOTHESIS: Nicotinamide phosphoribosyltransferase (NAMPT) is a multifunctional protein potentially involved in obesity and glucose metabolism. We systematically studied the association between circulating NAMPT, obesity, interventions and glucose metabolism and investigated potential underlying inflammatory mechanisms. METHODS: Fasting morning NAMPT serum levels were measured in cohorts of lean vs obese children, cohorts of intervention by lifestyle, exercise and bariatric surgery, and during an OGTT. In addition, mRNA expression, protein production and enzymatic activity of NAMPT were assessed from isolated leucocytes and subpopulations. RESULTS: Circulating NAMPT was significantly elevated in obese compared with lean children and declined after obesity interventions concomitantly with the decline in BMI, high-sensitivity C-reactive protein (hsCrP) and leucocyte counts. Circulating NAMPT significantly correlated with glucose metabolism and cardiovascular variables in univariate analyses, but only the association with glucose response during an OGTT was independent from BMI. We therefore assessed the NAMPT dynamic following an oral glucose load and found a significant decline of NAMPT levels to 77.0 ± 0.1% as a function of time, and insulin-to-glucose ratio during an OGTT in obese insulin-resistant adolescents. Circulating NAMPT was, however, most strongly associated with leucocyte counts (r = 0.46, p < 0.001). The leucocyte count itself determined significantly and independently from BMI insulin resistance in multiple regression analyses. We systematically evaluated NAMPT expression among several tissues and found that NAMPT was predominantly expressed in leucocytes. In subsequent analyses of leucocyte subpopulations, we identified higher NAMPT protein concentrations in lysates of granulocytes and monocytes compared with lymphocytes, whereas granulocytes secreted highest amounts of NAMPT protein into cell culture supernatant fractions. We confirmed nicotinamide mononucleotide enzymatic activity of NAMPT in all lysates and supernatant fractions. In monocytes, NAMPT release was significantly stimulated by lipopolysaccharide (LPS) exposure. CONCLUSIONS: Leucocytes are a major source of enzymatically active NAMPT, which may serve as a biomarker or even mediator linking obesity, inflammation and insulin resistance.

Retinol binding protein 4 (RBP4) is primarily associated with adipose tissue mass in children.

OBJECTIVE: Retinol binding protein 4 (RBP4) is a novel adipocytokine that may link obesity and insulin resistance. We aimed to discriminate between primary and secondary associations of RBP4 with obesity and related disease. DESIGN: We applied clinical and experimental approaches to investigate the association of RBP4 levels with normal development, obesity, metabolic and cardiovascular parameters in 68 lean and 61 obese children. RESULTS: RBP4 significantly increased with age and pubertal development in healthy lean children. Obese children had significantly higher RBP4 levels compared with lean controls (30.5±1.4 vs. 26.3±1.1 mg/L, P<0.05) and there was a clear association with BMI independent of age (r=0.33, P<0.0001). RBP4 levels correlated significantly with parameters of lipid and glucose metabolism, as well as cardiovascular parameters in univariate analyses. Multiple regression analyses confirmed the strong association of RBP4 with BMI z-score and age, while the association with most metabolic and cardiovascular parameters was abolished. To assess whether the association of RBP4 with obesity may be attributable to adipogenesis, we evaluated RBP4 expression and secretion during adipocyte differentiation using the human SGBS cell line. In preadipocytes, RBP4 mRNA expression was nearly undetectable but increased during differentiation up to approximately 1600-fold (P<0.05). Likewise, RBP4 secretion was restricted to mature adipocytes, further indicating that RBP4 is strongly related to differentiation of adipocytes. CONCLUSION: RBP4 is a marker of adipose tissue mass and obesity already evident in children. The association of RBP4 with metabolic and cardiovascular sequelae of obesity appears to be secondary to the underlying relationship wtih body fat.

Vaspin is related to gender, puberty and deteriorating insulin sensitivity in children.

BACKGROUND: Visceral adipose tissue-derived serine protease inhibitor (vaspin) has been suggested as a novel adipocytokine related to obesity and insulin sensitivity in adults. DESIGN: We quantified vaspin serum concentrations in 65 lean and 67 obese children and aimed to evaluate the relationship of vaspin with physical development, obesity, and metabolic and cardiovascular phenotypes in children. We further assessed the acute vaspin response to glucose provocation in 20 obese adolescents and evaluated tissue expression patterns of vaspin in humans. RESULTS: Vaspin levels were significantly higher in girls than in boys. In girls, vaspin increased with age and pubertal stage, whereas there was no change with development in boys. Obese girls had lower vaspin serum levels than those of lean controls, but there was no significant correlation with body mass index (BMI). Independent of sex, age and BMI, lower vaspin was associated with better insulin sensitivity, with higher systolic blood pressure and impaired endothelial function. In response to glucose provocation during an oral glucose tolerance test, vaspin serum levels declined by approximately 25% in adolescents with hyperinsulinemia, whereas there was no significant decline in normoinsulinemic patients. In support of our clinical data, we not only confirmed vaspin mRNA expression in adipose tissue but also found consistent expression of vaspin in the liver and indications for expression in the pancreas and the skin. CONCLUSION: We showed that gender differences in circulating vaspin levels develop during pubertal progression in girls. Although vaspin's association with obesity remains controversial, vaspin was increased with worsening insulin resistance already in children and was acutely down-regulated following glucose provocation in insulin-resistant adolescents independent of obesity. Besides adipose tissue, vaspin expression in the liver and the pancreas may potentially contribute to circulating vaspin levels and their regulation.

Perceived benefits and barriers to physical activity in a nationally representative sample in the European Union.

OBJECTIVE: To examine the attitudes of consumers, in particular their perceived benefits and barriers to physical activity from all EU member states, and having a measure of prevailing levels of activity, inactivity and self-reported body weight and body shape. DESIGN: Cross-sectional survey using an interview-assisted face-to-face questionnaire. SETTING: The survey was conducted between March and April 1997 in the 15 member states of the EU. SUBJECTS: Overall, 15,239 EU subjects, classified according to sex, age (six levels) and highest level of education attained (primary, secondary or tertiary), completed the survey. Sample selection of subjects in each EU member state was quota-controlled to ensure they were nationally representative. RESULTS: The most important motivation for people to participate in physical activity is to maintain good health (42%), to release tension (30%) and to get fit (30%). The importance of the health argument is highest in older persons and in subjects with a primary education level. Only 13% of the EU population (16% of women, 10% of men) perceived losing weight as a benefit of physical exercise. The most important barriers to increase physical activity are work or study commitments (28%) and the subjects' belief that they are not 'the sporty type' (25%). There is considerable between-country variation in the answering pattern within the EU.

Perceived need to alter eating habits among representative samples of adults from all member states of the European Union.

OBJECTIVE: To examine the perceived need to alter eating habits among nationally-representative samples from each member state of the European Union (EU). DESIGN: A cross-sectional study in which quota-controlled, nationally-representative samples of approximately 1000 adults from each country completed a face-to-face interview-assisted questionnaire. SETTING: The survey was conducted between October 1995 and February 1996 in the 15 member states of the European Union. SUBJECTS: 14,331 subjects (aged 15 y upwards) completed the questionnaire. Data were weighted by population size for each country and by sex, age and regional distribution within each member state. RESULTS: 71% of EU subjects agreed with the statement 'I do not need to make changes to the food I eat, as it is already healthy enough'. There was wide variation between the member states ranging from 47% in Finland to 87% in Italy indicating agreement. Overall there was little difference between the sexes except in Austria, Belgium, Germany, Greece and Ireland, but the proportions of subjects agreeing with the statement generally increased with advancing age and decreased with higher levels of education. The effects of demographics were not consistent across member states. A total of 49% of EU subjects agreed with the statement 'I usually do not think of the nutritional aspects of the food I eat'. Significantly more females than males disagreed with the statement in all countries except Portugal. In all member states there were widespread beliefs that people in general should decrease their consumption of savoury snacks and increase their consumption of fruit and vegetables. CONCLUSIONS: The results of this study demonstrate that dietary advice may not be perceived as personally relevant among EU subjects. In addition important target groups for the promotion of healthy eating have been identified for example, males or subjects with low levels of education. Because of the variation in attitudes a single pan-EU healthy eating programme is unlikely to be effective for all countries or for different demographic groups.

Perceived benefits of healthy eating among a nationally-representative sample of adults in the European Union.

OBJECTIVE: To determine the main perceived benefits associated with healthy eating among European adults. Efforts to make a healthy diet more attractive have to be based on motives capable of stimulating alterations in nutritional behaviour. DESIGN: A cross-sectional study in which quota-controlled, nationally-representative samples of approximately 1000 adults from each country completed a face-to-face interview-assisted questionnaire. SETTING: The survey was conducted between October 1995 and February 1996 in the 15 member states of the European Union. SUBJECTS: A total of 14331 subjects (aged 15 y upwards) completed the questionnaire. Data were weighted by population size for each country and by sex, age and regional distribution within each member state. RESULTS: The question 'which specific benefits, if any, would you personally believe can be achieved by healthy eating'? was answered from a collection of 9 given items with stay healthy by 67% of subjects, with prevent disease by 66%, with be fit by 53%, with control weight by 53% and with quality of life by 45%. The most important personal benefit was asked by the question 'which one benefit would be the most personally significant for you'? 31% of subjects stated stay healthy, 24% prevent disease, 10% control weight, 10% quality of life, 9% be fit. The frequency of answered statements differed considerably between the EU countries, however, no regional structure was detected. More women then men expected benefits from healthy eating. With increasing age more people tended to believe in the benefits stay healthy and prevent disease. Be fit was a more important benefit for younger people (aged 15-34 y). People with a higher level of education associated more benefits from healthy eating.

[Health promotion and nutrition counseling for obese patients--a responsibility of medical care]. / Gesundheitsförderung und Ernährungsberatung von Ubergewichtigen--eine Aufgabe in der ärztlichen Betreuung.

For prevention and therapy of overweight the joined effort of physicians and nutritional consultants is suggested to be the most effective approach. To develop a model of cooperation, the present situation of communication has been analyzed by questioning 57 overweight volunteers (by questionnaire), 34 physicians (both by questionnaire and interview), and 4 nutritional consultants (by interview). The physicians and the nutritional consultants feel the lack of communication and they express the wish to improve the cooperation. There is also a need for organizing structures of such collaboration, e.g. nutritional consultation either as part of the medical practice or as a special practice where the patient is to be referred to.

[Selected results of attitudes regarding nutrition behavior in the former East Germany]. / Ausgewählte Ergebnisse zu Einstellungen im Ernährungsverhalten in der ehemaligen DDR.

In studying the causes of individual nutritional behaviour not only the economic, social, demographic, cultural and other determinants are of importance but also psychological processes of decision and evaluation. For recording the attitudes, value-orientations and action goals a questionnaire was developed (72 items, 13 social and nutrition-related features). It was completed by 867 subjects aged between 18 and 65 years. The statistical analysis shows that the action-determining goals investigated can be classified in 5 empirically developed, factorially validated scales (expenditure, health, enjoyment, matter of minor importance, stimulus). Besides, significant relationships were revealed between the scales and the social characteristics as e.g. sex, age, education, occupation, household size, cooking, mass catering, and self-assessment of body weight.

[The formation of eating behavior]. / Zur Entstehung des Ernährungsverhaltens.

Food behaviour involves the totality of the actions of man which aim at satisfying his nutritional need. It is based on psychical reflection, decision and assessment processes. Food behaviour has social and historical determinants and forms accordingly to the dialectic relation of biological, social and economic conditions. Hunger, thirst and appetite are perceived as nutritional need which results from the requirements of energy, nutrients and liquid, and is satisfied by the food behaviour in conformity with the actual material potential, situational influences, subjective ideas, interests, attitudes and knowledge as well as other psychical properties. Consequently, food behaviour is rich in variations with dynamic and conservative features. Motives as well as will components are essential constituent conditions of food behaviour. For this reason, empirical studies arteo provide psychological cognition concerning the subjective reflection of the nutritional requirements, the requirement-standard integration, the sensation of stimulation and the decision-making in food behaviour, the ultimate goal being to deduce measures for food behaviour guidance.