After weight loss, changes in the circulating levels of several peripheral hormones involved in the homeostatic regulation of body weight occur. Whether these changes are transient or persist over time may be important for an understanding of the reasons behind the high rate of weight regain after diet-induced weight loss.
1 May 2013 in European Journal of Clinical Nutrition
The coefficient of variation (CV) is commonly used to measure relative dispersion. However, since it is based on the sample mean and standard deviation, outliers can adversely affect it. Additionally, for skewed distributions the mean and standard deviation may be difficult to interpret and, consequently, that may also be the case for the . Here we investigate the extent to which quantile-based measures of relative dispersion can provide appropriate summary information as an alternative to the CV. In particular, we investigate two measures, the first being the interquartile range (in lieu of the standard deviation), divided by the median (in lieu of the mean), and the second being the median absolute deviation, divided by the median, as robust estimators of relative dispersion. In addition to comparing the influence functions of the competing estimators and their asymptotic biases and variances, we compare interval estimators using simulation studies to assess coverage.
Is there a dose-response effect of exercise on inflammation, fatigue and activity in cancer survivors? Systematic review with meta-regression analysis of randomised trials. Adults diagnosed with cancer, regardless of specific diagnosis or treatment. Exercise interventions including aerobic and/or resistance as a key component. The primary outcome measures were markers of inflammation (including C-reactive protein and interleukins) and various measures of fatigue. The secondary outcomes were: measures of activity, as defined by the World Health Organization's International Classification of Functioning, Disability and Health, including activities of daily living and measures of functional mobility (eg, 6-minute walk test, timed sit-to-stand and stair-climb tests). Risk of bias was evaluated using the PEDro scale, and overall quality of evidence was assessed using the Grades of Research, Assessment, Development and Evaluation (GRADE) approach. Forty-two trials involving 3816 participants were included. There was very low-quality to moderate-quality evidence that exercise results in significant reductions in fatigue (SMD 0.32, 95% CI 0.13 to 0.52) and increased walking endurance (SMD 0.77, 95% CI 0.26 to 1.28). A significant negative association was found between aerobic exercise intensity and fatigue reduction. A peak effect was found for moderate-intensity aerobic exercise for improving walking endurance. No dose-response relationship was found between exercise and markers of inflammation or exercise duration and outcomes. Rates of adherence were typically high and few adverse events were reported. Exercise is safe, reduces fatigue and increases endurance in cancer survivors. The results support the recommendation of prescribing moderate-intensity aerobic exercise to reduce fatigue and improve activity in people with cancer. PROSPERO CRD42015019164.
Background: In the context of increased asthma exacerbations associated with climatic changes such as thunderstorm asthma, interest in establishing the link between pollen exposure and asthma hospital admissions has intensified. Here, we systematically reviewed and performed a meta‐analysis of studies on pollen and emergency department (ED) attendance.Methods: A search for studies with appropriate search strategy in MEDLINE, EMBASE, Web of Science and CINAHL was conducted. Each study was assessed for quality and risk of bias. The available evidence was summarized both qualitatively and meta‐analysed using random‐effects models when moderate heterogeneity was observed.Results: Fourteen studies were included. The pollen taxa investigated differed between studies, allowing meta‐analysis only of the effect of grass pollen. A statistically significant increase in the percentage change in the mean number of asthma ED presentations (MPC) (pooled results from 3 studies) was observed for an increase in 10 grass pollen grains per cubic metre of exposure 1.88% (95% CI = 0.94%, 2.82%). Time series studies showed positive correlations between pollen concentrations and ED presentations. Age‐stratified studies found strongest associations in children aged 5‐17 years old.Conclusion: Exposure to ambient grass pollen is an important trigger for childhood asthma exacerbations requiring ED attendance. As pollen exposure is increasingly a problem especially in relation to thunderstorm asthma, studies with uniform measures of pollen and similar analytical methods are necessary to fully understand its impact on human health.