Robert Winker

Endurance Exercise Training in Orthostatic Intolerance A Randomized, Controlled Trial

Orthostatic intolerance is a syndrome characterized by chronic orthostatic symptoms of light-headedness, fatigue, nausea, orthostatic tachycardia, and aggravated norepinephrine levels while standing. The aim of this study was to assess the protective effect of exercise endurance training on orthostatic symptoms and to examine its usefulness in the treatment of orthostatic intolerance. 2768 military recruits were screened for orthostatic intolerance by questionnaire. Tilt-table testing identified 36 cases of orthostatic intolerance out of the 2768 soldiers. Subsequently, 31 of these subjects with orthostatic intolerance entered a randomized, controlled trial. The patients were allocated randomly to either a “training” (3 months jogging) or a “control” group. The influence of exercise training on orthostatic intolerance was assessed by determination of questionnaire scores and tilt-table testing before and after intervention. After training, only 6 individuals of 16 still had orthostatic intolerance compared with 10 of 11 in the control group. The Fisher exact test showed a highly significant difference in diagnosis between the 2 groups (P=0.008) at the end of the study. Analysis of the questionnaire-score showed significant interaction between time and group (P=0.001). The trained subjects showed an improvement in the average symptom score from 1.79±0.4 to 1.04±0.4, whereas the control subjects showed no significant change in average symptom score (2.09±0.6 and 2.14±0.5, respectively). Our data demonstrate that endurance exercise training leads to an improvement of symptoms in the majority of patients with orthostatic intolerance. Therefore, we suggest that endurance training should be considered in the treatment of orthostatic intolerance patients.

Mitochondrial DNA haplogroup T is associated with coronary artery disease and diabetic retinopathy: a case control study

BackgroundThere is strong and consistent evidence that oxidative stress is crucially involved in the development of atherosclerotic vascular disease. Overproduction of reactive oxygen species (ROS) in mitochondria is an unifying mechanism that underlies micro- and macrovascular atherosclerotic disease. Given the central role of mitochondria in energy and ROS production, mitochondrial DNA (mtDNA) is an obvious candidate for genetic susceptibility studies on atherosclerotic processes. We therefore examined the association between mtDNA haplogroups and coronary artery disease (CAD) as well as diabetic retinopathy.MethodsThis study of Middle European Caucasians included patients with angiographically documented CAD (n = 487), subjects with type 2 diabetes mellitus with (n = 149) or without (n = 78) diabetic retinopathy and control subjects without clinical manifestations of atherosclerotic disease (n = 1527). MtDNA haplotyping was performed using multiplex PCR and subsequent multiplex primer extension analysis for determination of the major European haplogroups. Haplogroup frequencies of patients were compared to those of control subjects without clinical manifestations of atherosclerotic disease.ResultsHaplogroup T was significantly more prevalent among patients with CAD than among control subjects (14.8% vs 8.3%; p = 0.002). In patients with type 2 diabetes, the presence of diabetic retinopathy was also significantly associated with a higher prevalence of haplogroup T (12.1% vs 5.1%; p = 0.046).ConclusionOur data indicate that the mtDNA haplogroup T is associated with CAD and diabetic retinopathy in Middle European Caucasian populations.

A meta-analysis for neurobehavioural effects due to electromagnetic field exposure emitted by GSM mobile phones

Background and objective: Numerous studies have investigated the potential effects of electromagnetic fields (EMFs) emitted by GSM mobile phones (∼900 MHz to ∼1800 MHz) on cognitive functioning, but results have been equivocal. In order to try and clarify this issue, the current study carried out a meta-analysis on 19 experimental studies. Design: Meta-analysis. Methods: Nineteen studies were taken into consideration. Ten of them were included in the meta-analysis as they fulfilled several minimum requirements; for example, single-blind or double-blind experimental study design and documentation of means and standard deviation of the dependent variables. The meta-analysis compared exposed with non-exposed subjects assuming that there is a common population effect so that one single effect size could be calculated. When homogeneity for single effect sizes was not given, an own population effect for each study and a distribution of population effects was assumed. Results: Attention measured by the subtraction task seems to be affected in regard to decreased reaction time. Working memory measured by the N-back test seems to be affected too: under condition 0-back target response time is lower under exposure, while under condition 2-back target response time increases. The number of errors under condition 2-back non-targets appears to be higher under exposure. Conclusion: Results of the meta-analysis suggest that EMFs may have a small impact on human attention and working memory.

Why life oscillates : from a topographical towards a functional chronobiology

Chronobiology has identified a multitude of rhythms within our body as well as within each living cell. Some of these rhythms, such as the circadian and circannual, interact with our environment, while others run on their own, but are often coupled to the circadian or to other body rhythms. Recent evidence shows that these rhythms might be more important for our health than expected: Disturbance of the circadian rhythms by jet lag or shift work not only evokes autonomic disturbances but also increases the incidence of cancer, as shown in this issue of Cancer Causes and Control. The occurrence of rhythms in the organism obviously bears several advantages: (1) It increases organismic stability by calibrating the system’s characteristics: Regulation curves in time and space are crucial for controlling physiological long-term stability. To determine its properties continuously the system varies its parameters slightly over several time scales at different frequencies—akin to what our body does, e.g. in heart-rate variability. (2) Tuning and synchronization of rhythms saves energy: It was Huygens who observed that clocks on a wall tend to synchronize their beats. It turned out later that synchronisation is a very common phenomenon observed in bodies’ rhythms and can be found, for example, when we relax or sleep. At such times energy consumption is minimal, our body working most efficiently. (3) Temporal compartmentalization allows polar events to occur in the same space unit: there are polarities in the universe of our body, which cannot happen simultaneously. Systole and diastole, inspiration and expiration, work and relaxation, wakefulness and sleep, reductive and oxidative states cannot be performed efficiently at the same time and place. Temporal compartmentalization is probably the most efficient way to mediate between these polarities. Chronobiology and chronomedicine are opening a new and very exciting understanding of our bodies’ regulation. The biological time and its oscillations gain more attention and importance as these interrelations are understood.

No effects of short-term exposure to mobile phone electromagnetic fields on human cognitive performance: a meta-analysis.

During recent years, a large number of studies on the effects of electromagnetic fields emitted by cellular mobile phones on human cognitive performance have been carried out. However, the results have been ambiguous. We carried out the current meta-analysis in order to investigate the impact of electromagnetic fields emitted by mobile phones on human cognition. Seventeen studies were included in the meta-analysis as they fulfill several requirements such as single- or double-blind experimental study design, and documentation of means and standard deviations of dependent variables. The meta-analysis was carried out as a group comparison between exposed and non-exposed subjects. No significant effects of electromagnetic fields emitted by Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) mobile phones were found. Cognitive abilities seem to be neither impaired nor facilitated. Results of the meta-analysis suggest that a substantial short-term impact of high frequency electromagnetic fields emitted by mobile phones on cognitive performance can essentially be ruled out.

Endothelial NO Synthase Polymorphisms and Postural Tachycardia Syndrome

Postural tachycardia syndrome (POTS) is a heterogeneous disorder characterized by an excessive rise in heart rate and symptoms consistent with cerebral hypoperfusion in the upright position. NO produced by endothelial NO synthase is a significant factor in the regulation of blood flow. Genetic polymorphisms in the promoter region (T-786C) and exon 7 (E298D) of the NO synthase isoform 3 gene affect enzyme activity and have been associated with a number of cardiovascular diseases. Because some findings in POTS suggest aberrant NO-mediated functions, we postulated that the variant genotypes of these polymorphisms may increase the risk of developing POTS and correlate with more severe symptoms. We genotyped 136 patients with POTS (mean age 32.2±9.9 years; 46 men and 90 women) from Nashville, Tenn, and Vienna, Austria, and compared them with 191 healthy volunteers (mean age 29.1±8.0 years; 127 men and 64 women). Participants also underwent orthostatic testing with blood pressure, heart rate, and plasma norepinephrine measurements while supine and upright. The frequencies of the -786CC and 298DD genotypes were significantly lower in patients with POTS than in control subjects (odds ratio [OR], 0.28; 95% confidence interval [CI], 0.14 to 0.57; P=0.001 for -786CC; and OR, 0.44; 95% CI, 0.21 to 0.91; P=0.033 for 298DD). According to 2-locus genotype analyses, patients with -786CC and 298EE or 298ED experienced the largest changes in heart rate and plasma norepinephrine with standing. These results indicate that NO may influence the development of POTS and the severity of POTS symptoms.

Acute effects of electromagnetic fields emitted by GSM mobile phones on subjective well-being and physiological reactions: A meta-analysis

The potential effects of radiofrequency electromagnetic fields (RF-EMF) emitted by GSM mobile phones on subjective symptoms, well-being and physiological parameters have been investigated in many studies. However, the results have been ambiguous. The current meta-analysis aims to clarify whether RF-EMF have an influence on well-being in self-reported sensitive persons, as well as in non-sensitive people. A literature search revealed 17 studies including 1174 participants. The single effects for various subjective and objective outcomes were meta-analytically combined to yield a single population parameter. Dependant variables were subjective (e.g. headaches) and objective parameters (e.g. heart rate variability) of well-being. The results show no significant impact of short-term RF-EMF exposure on any parameter. Future research should focus on the possible effects of long-term exposure.

Cognitive function in elderly marathon runners: Cross-sectional data from the marathon trial (apsoem)

ZusammenfassungHINTERGRUND: Die kognitive Beeinträchtigung von älteren Menschen trägt zur Morbidität, Verlust der Lebensqualität und Beeinträchtigung der Arbeitsfähigkeit in alternden westlichen Gesellschaften bei. Strategien zur Erhaltung der kognitiven Fähigkeiten im hohen Alter stellen daher eine große Herausforderung für die Arbeitsmedizin dar. ZIEL: Festzustellen, ob intensives Ausdauertraining mit einer verbesserten kognitiven Leistungsfähigkeit verbunden ist, und ob brain-derived neurotrophic factor (BDNF) und insulin-like growth factor (IGF) durch Ausdauertraining erhöht werden. METHODIK: Aktive ältere Marathonläufer oder Radfahrer über 60 Jahre wurden angeworben und einer inaktiven Kontrollgruppe nach Alter, Geschlecht und Bildungsjahren gegenübergestellt. Nachdem laut Studienprotokoll Personen mit verschiedenen Krankheiten ausgeschlossen wurden, konnten 56 Athleten und 58 Kontrollpersonen für Folgeuntersuchungen herangezogen werden. Der Einfluss von Ausdauertraining auf kognitive Funktionen wurde durch die Vienna Neuropsychologische Testbatterie (VNTB) und die CERAD Testbatterie (Consortium to Establish a Registry for Alzheimers Disease) gemessen. Andere relevante Ergebnisse waren die Werte der humoralen Wachstumsfaktoren (BDNF und IGF-1), Apo ε4 Carrierfrequenz und Selbsteinschätzungen. ERGEBNISSE: Die Leistung der älteren Marathongruppe war nur bei einer spezifischen kognitiven Aufgabe besser (beim Five Point Test, p = 0,04) und fast signifikant besser in einem zusätzlichen Test (NAI Stroop Test, p = 0,08). Weder BDNF noch IGF-1 hatten einen Bezug zur Dauer des täglichen Ausdauertrainings, und kein Unterschied wurde bei den Basalwerten dieser Wachstumsfaktoren in den Trainings- und Kontrollkohorten gefunden. Interessanterweise fanden wir auch signifikant reduzierte BDNF-Werte bei Personen mit Alzheimerkrankheit in der Familie trotz Beibehaltung der normalen kognitiven Leistung (p = 0,01). SCHLUSSFOLGERUNG: Diese Ergebnisse deuten darauf hin, dass umfassendes Ausdauertraining für die Erhaltung der kognitiven Funktionen von älteren Menschen nützlich sein könnte. Längsschnittdaten dieser prospektiven Kohortenstudie sind notwendig, um diese möglichen Auswirkungen auf Kognition zu bewerten. Zusätzlich zeigen unsere Daten, dass die nützlichen Auswirkungen von Ausdauertraining nicht mit der Hochregulation von Neurotrophinen wie BDNF und IGF-1 verbunden sind. Da wir reduzierte BDNF-Werte bei Personen mit einer positiven Familiengeschichte von Alzheimer fanden, vermuten wir, dass eine BDNF-Senkung einer kognitiven Beeinträchtigung vorausgehen könnte.SummaryBACKGROUND: Cognitive impairment of the elderly contributes to morbidity, loss of quality of life, and impairment of work ability in aging western societies. Thus strategies to maintain cognitive function at an advanced age imply a great challenge to Occupational Medicine. AIM: To study whether intensive endurance exercise training is associated with better cognitive performance and increases brain-derived neurotrophic factor (BDNF) and insulin-like growth factor (IGF). METHODS: Active elderly marathon runners or bicyclists older than 60 years were recruited and matched with an inactive control group according to age, sex, and education years. After exclusion of various diseases according to the study protocol 56 athletes and 58 controls could be selected for follow-up studies. The influence of endurance training on cognitive function was assessed by the use of the Vienna Neuropsychological Test Battery and the CERAD test battery. Other relevant outcomes were the levels of BDNF, IGF-1, Apo e4 carrier state, and self-ratings. RESULTS: The elderly marathon group performed better only in one specific cognitive task (the Five Point Test, p = 0.04) and almost significantly better in one additional test (the NAI Stroop Test, p = 0.08). Neither BDNF nor IGF-1 was related to the duration of daily exercise and no differences in the basal levels of these humoral growth factors in the exercise and the control cohort were found. Interestingly, we also found significantly decreased BDNF levels in subjects with Alzheimers disease in the family in spite of the maintained normal cognitive performance (p = 0.01). CONCLUSION: These results suggest that extensive endurance exercise training might be beneficial for maintaining cognitive function in elderly persons. Our data demonstrate that beneficial endurance training effects are not linked to the upregulation of the examined neurotrophins. Since we found reduced BDNF-levels in subjects with a positive family history of Alzheimers disease, we speculate that BDNF-reduction might precede cognitive impairment.

Socioeconomic Factors and Suicide: An Analysis of 18 Industrialized Countries for the Years 1983 Through 2007

Objective: To evaluate the association between socioeconomic factors and suicide rates. Methods: Analysis of time series of suicide rates, gross domestic product, unemployment rates, labor force participation, and divorce rates of 18 countries are analyzed by the application of panel-vector error correction models. Main outcome measures are the association between the socioeconomic factors and suicide rates. Results: Decreasing economic growth and increasing divorce rates are significantly associated with increasing suicide rates in men. For women, increasing economic growth, increasing unemployment, and increasing divorce rates are significantly associated with increasing suicides. Increasing female labor force participation is associated with decreasing suicides. Conclusion: Socioeconomic factors are associated with suicide rates. However, this relationship differs by sex. The current results provide a strong argument that suicide prevention strategies must include the monitoring of socioeconomic development.

Economic growth and the incidence of occupational injuries in Austria

ZusammenfassungZIEL: Das Ziel der vorliegenden Studie bestand darin, den möglichen Einfluss des Wirtschaftswachstums gemessen durch das Bruttoinlandsprodukt auf die Inzidenz von Arbeitsunfällen in Österreich zu untersuchen. METHODIK: Die Beziehung zwischen dem Bruttoinlandsprodukt und Arbeitsunfällen von österreichischen Angestellten wurde zwischen den Jahren 1955 und 2004 mittels eines Fehlerkorrekturmodells analysiert. Im Jahr 1955 bestand die Stichprobe aus 1,568.371 Personen. 2004 umfasste sie 2,656.952 Personen. Die Arbeitsunfälle wurden in Unfälle mit tödlichem und mit nichttödlichem Ausgang unterteilt. RESULTATE: Zwischen 1955 und 2004 sank die Gesamtunfallrate von 8,59% auf 4,08%. Unfälle mit tödlichem Ausgang sanken von 0,03% auf 0,01%. Die Rate der Unfälle ohne tödlichem Ausgang halbierte sich von 8,56% auf 4,07%. Das österreichische Bruttoinlandsprodukt stieg von 37,7 Milliarden Euro auf 202,8 Milliarden Euro (Basis 1995). Die statistische Analyse zeigte, dass steigender Wohlstand deutlich mit sinkenden Arbeitsunfallraten (tödlich und nicht tödlich) assoziiert ist. Dieser Zusammenhang lässt sich einerseits dadurch erklären, dass in Zeiten der Rezession weniger Investitionen in neue und sichere Technologien sowie in den betriebsinternen Arbeitnehmerschutz investiert wird. Andererseits erhöht die Angst vor Arbeitslosigkeit, die in Rezessionsphasen deutlicher ausgeprägt ist, das Unfallrisiko. SCHLUSSFOLGERUNGEN: Die ökonomische Entwicklung hat Auswirkungen auf die Inzidenz von Arbeitsunfällen. Gerade während Phasen des verlangsamten Wirtschaftswachstums und in Phasen der Rezession sollten die Maßnahmen zur Steigerung der Arbeitssicherheit und zur Unfallprävention verstärkt werden.SummaryOBJECTIVES: The aim of this paper was to analyze the impact of economic growth measured by real gross domestic product (GDP) on the incidence of occupational injuries in Austria. METHODS: The relationship between GDP and the occupational injury rate of the wage-earning population between 1955 and 2004 was analyzed using an error correction model. The sample size increased from 1.568,371 persons in 1955 to 2.656,952 in 2004. Occupational injuries were divided into fatal and non-fatal injuries. RESULTS: Occupational injuries (fatal and non-fatal) decreased from 8.59% to 4.08%: non-fatal injuries decreased from 8.56% to 4.07%; fatal injuries decreased from 0.03% to 0.01%. Austrian GDP increased from EUR 37.7 billion to EUR 202.8 billion (base year 1995). Statistical analysis clearly shows that a growing economy is associated with declining injury rates (fatal and non-fatal). Two mechanisms are discussed. Firstly, rising GDP is accompanied by greater investment in safer technologies and occupational safety measures. Secondly, booming economies are associated with a reduced risk of unemployment, which is already known to be a risk factor for occupational injuries. CONCLUSIONS: Economic development appears to have an impact on the incidence of occupational injuries in Austria. Health policy should emphasize the necessity for safety at work particularly in phases of economic slowdown.