In this study, the levels of circulating mediators of appetite that change after weight loss and promote weight regain did not revert to the values recorded before weight loss. Long-term strategies ...to counteract these changes may be needed to prevent obesity relapse.
Worldwide, there are more than 1.5 billion overweight adults, including 400 million who are obese.
1
Although dietary restriction often results in initial weight loss, the majority of obese dieters fail to maintain their reduced weight.
2
Understanding the barriers to maintenance of weight loss is crucial for the prevention of relapse.
Body weight is centrally regulated, with peripheral hormonal signals released from the gastrointestinal tract, pancreas, and adipose tissue integrated, primarily in the hypothalamus, to regulate food intake and energy expenditure.
3
The number of identified peripheral modulators of appetite is expanding rapidly and includes leptin, ghrelin, cholecystokinin, peptide YY, insulin, pancreatic . . .
Abstract Question: Is there a dose-response effect of exercise on inflammation, fatigue and activity in cancer survivors? Design: Systematic review with meta-regression analysis of randomised trials. ...Participants: Adults diagnosed with cancer, regardless of specific diagnosis or treatment. Intervention: Exercise interventions including aerobic and/or resistance as a key component. Outcome measures: 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. Results: 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. Conclusions: 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. Review registration: PROSPERO CRD42015019164. Dennett AM, Peiris CL, Shields N, Prendergast LA, Taylor NF (2016) Moderate-intensity exercise reduces fatigue and improves mobility in cancer survivors: a systematic review and meta-regression. Journal of Physiotherapy 62: 68–82
Guidelines recommend gradual weight loss for the treatment of obesity, indicative of a widely held opinion that weight lost rapidly is more quickly regained. We aimed to investigate the effect of the ...rate of weight loss on the rate of regain in obese people.
For this two phase, randomised, non-masked, dietary intervention trial in a Melbourne metropolitan hospital, we enrolled 204 participants (51 men and 153 women) aged 18–70 years with a BMI between 30 and 45 kg/m2. During phase 1, we randomly assigned (1:1) participants with a block design (block sizes of 2, 4, and 6) to account for sex, age, and BMI, to either a 12-week rapid weight loss or a 36-week gradual programme, both aimed at 15% weight loss. We placed participants who lost 12·5% or more weight during phase 1 on a weight maintenance diet for 144 weeks (phase 2). The primary outcome was mean weight loss maintained at week 144 of phase 2. We investigated the primary outcome by both completers only and intention-to-treat analyses. This study is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12611000190909.
200 participants were randomly assigned to the gradual weight loss (n=103) or rapid weight loss (n=97) programme between Aug 8, 2008, and March 9, 2010. After phase 1, 51 (50%) participants in the gradual weight loss group and 76 (81%) in the rapid weight loss group achieved 12·5% or more weight loss in the allocated time and started phase 2. At the end of phase 2, both gradual weight loss and rapid weight loss participants who completed the study (n=43 in gradual weight loss and n=61 in rapid weight loss) had regained most of their lost weight (gradual weight loss 71·2% regain, 95% CI 58·1–84·3 vs rapid weight loss 70·5%, 57·8–83·2). Intention-to-treat analysis showed similar results (gradual weight loss 76·3% regain, 95% CI 65·2–87·4 vs rapid weight loss 76·3%, 65·8–86·8). In phase 1, one participant in the rapid weight loss group developed cholecystitis, requiring cholecystectomy. In phase 2, two participants in the rapid weight loss group developed cancer.
The rate of weight loss does not affect the proportion of weight regained within 144 weeks. These findings are not consistent with present dietary guidelines which recommend gradual over rapid weight loss, based on the belief that rapid weight loss is more quickly regained.
The Australian National Health and Medical Research Council and the Sir Edward Dunlop Medical Research Foundation.
Robust analogs to the coefficient of variation Arachchige, Chandima N. P. G.; Prendergast, Luke A.; Staudte, Robert G.
Journal of applied statistics,
01/2022, Letnik:
49, Številka:
2
Journal Article
Recenzirano
Odprti dostop
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
${\rm CV} $
CV
. 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.
Whether testosterone treatment has benefits on body composition over and above caloric restriction in men is unknown. We hypothesised that testosterone treatment augments diet-induced loss of fat ...mass and prevents loss of muscle mass.
We conducted a randomised double-blind, parallel, placebo controlled trial at a tertiary referral centre. A total of 100 obese men (body mass index ≥ 30 kg/m
) with a total testosterone level of or below 12 nmol/L and a median age of 53 years (interquartile range 47-60) receiving 10 weeks of a very low energy diet (VLED) followed by 46 weeks of weight maintenance were randomly assigned at baseline to 56 weeks of 10-weekly intramuscular testosterone undecanoate (n = 49, cases) or matching placebo (n = 51, controls). The main outcome measures were the between-group difference in fat and lean mass by dual-energy X-ray absorptiometry, and visceral fat area (computed tomography).
A total of 82 men completed the study. At study end, compared to controls, cases had greater reductions in fat mass, with a mean adjusted between-group difference (MAD) of -2.9 kg (-5.7 to -0.2; P = 0.04), and in visceral fat (MAD -2678 mm
; -5180 to -176; P = 0.04). Although both groups lost the same lean mass following VLED (cases -3.9 kg (-5.3 to -2.6); controls -4.8 kg (-6.2 to -3.5), P = 0.36), cases regained lean mass (3.3 kg (1.9 to 4.7), P < 0.001) during weight maintenance, in contrast to controls (0.8 kg (-0.7 to 2.3), P = 0.29) so that, at study end, cases had an attenuated reduction in lean mass compared to controls (MAD 3.4 kg (1.3 to 5.5), P = 0.002).
While dieting men receiving placebo lost both fat and lean mass, the weight loss with testosterone treatment was almost exclusively due to loss of body fat.
clinicaltrials.gov, identifier NCT01616732 , registration date: June 8, 2012.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
As a measure of heterogeneity in meta‐analysis, the coefficient of variation (CV) has been recently considered, providing researchers with a complement to the very popular I2 measure. While I2 ...measures the proportion of total variance that is due to variance of the random effects, the CV is the ratio of the standard deviation of the random effects to the effect of interest. Consequently, the CV provides a different measure of the extent of heterogeneity in a meta‐analysis relative to the effect being measured. However, very large CV values can occur when the effect is small making interpretation difficult. The purpose of this article is two‐fold. First, we consider variants of the CV that exist in the interval 0,1 which may be preferable for some researchers. Second, we provide interval estimators for the CV and its variants with excellent coverage properties. We perform simulation studies based on simulated and real data sets and draw comparisons between the methods. For both the CV and its transformations, we recommend confidence intervals using the propagating imprecision method or, as a simpler alternative but at the expense of slightly worse performance in terms of coverage, combining reduced‐coverage confidence intervals for the two parameters. These interval estimators typically have better coverage properties for the CV measure than those previously considered.
Objective
The aim of this study was to determine whether the hormone changes following weight loss are proportional to the degree of weight loss and to starting BMI.
Methods
A very low‐energy diet ...was used to achieve 15% weight loss. Fasting and postprandial gut hormones and leptin were measured during a meal test at baseline and at 5% (1%), 10% (2%), and 15% (2.5%) weight loss. Linear mixed‐effects models were used to analyze hormone changes.
Results
From baseline to 5% weight loss, decreases were seen in fasting concentrations of leptin (−8.25 ng/mL; p < 0.001), amylin (−21.3 pg/mL; p < 0.001), and glucagon‐like peptide 1 (−59.55 pg/mL; p < 0.001). There was a small further reduction in leptin between 5% and 15% weight loss (−1.88 ng/mL; p = 0.019) but not in glucagon‐like peptide 1 and amylin. Fasting ghrelin showed a significant increase at 10% weight loss (41.64 pg/mL; p = 0.002), with a nonsignificant increase from 10% to 15% loss (26.03 pg/mL; p = 0.065). Postprandial changes in hormone levels were variable. There was no correlation between baseline weight and the degree of hormone changes.
Conclusions
The majority of changes in fasting gut hormones and leptin occurred in early weight loss, with minor further changes up to 15% weight loss. Starting weight did not affect the degree of hormone change.
Abstract
Background
Obesity contributes to disability in older adults, and this is offset by weight loss and exercise. Very Low Calorie Diets (VLCDs) achieve rapid weight loss; however, these have ...not been rigorously evaluated in older people.
Methods
A randomized trial was conducted from August 2012 through December 2015. The intervention was 12 weeks of thrice weekly exercise combined with either healthy eating advice (Ex/HE), hypocaloric diet (Ex/Diet), or VLCD (Ex/VLCD). Outcomes were physical function, measured by 6-minute walk test (6MWT) and De Morton Mobility Index (DEMMI). Other measures were body composition measured by Dual Energy X-Ray Absorptiometry, and nutritional parameters (albumin, vitamins B12 and D, ferritin and folate).
Results
36, 40, and 41 participants were randomized to Ex/HE, Ex/Diet, and Ex/VLCD, respectively. At 12 weeks, weight was reduced by 3.7, 5.1, and 11.1% (p < .01), respectively. Ex/VLCD had significant reduction in fat (16.8%), lean mass (4.8%), and bone mineral density (1.2%), but increased relative lean mass (3.8%). DEMMI improved by 14.25, 14.25, and 13.75 points in Ex/HE, Ex/Diet, and Ex/VLCD, respectively; however, there was no between-group difference (p = .30). 6MWT improved by 53.1, 64.7, and 84.4 meters in Ex/HE, Ex/Diet, and Ex/VLCD (p = .18). Post hoc stratification for gender and adjustment for initial physical function and type 2 diabetes only revealed significant between-group differences for men in the 6MWT, with improvement by 57.8, 77.8, and 140.3 meters in Ex/HE, Ex/Diet, and Ex/VLCD, respectively (p = .01). Improvements in nutritional parameters were seen in Ex/VLCD, but not in Ex/HE and Ex/Diet. The VLCD was well tolerated.
Conclusions
VLCDs have potential in the treatment of obesity in older persons; of particular benefit is improvement in nutritional status. The gait speed improvement observed in men warrants further investigation.
Background
Allergic disease is a recognized global epidemic and a significant cause of ill health and poor quality of life. The prevalence of pollen allergy is high throughout the world, and pollen ...exposure itself plays a role in emergency department presentations and hospitalizations for asthma. Lung function and airway inflammation are important measures of asthma activity and control.
Objective
To examine associations between exposure to multiple pollen types and lung function and markers of airway inflammation at 8 and 14 years of age, and to explore potential modification by residential greenness.
Methods
A cohort of high‐risk children living in Sydney, Australia had spirometry and fractional exhaled nitric oxide (FeNO) measured at 8 and 14 years of age. Ambient pollen concentration on the day of lung function measurement and up to three days prior was used as the exposure measure. Residential greenness was derived from satellite imagery. We modelled the association between six pollen types and lung function and FeNO. We also assessed modifying effects of residential greenness.
Results
Casuarina, cypress and Pinus pollen in the air the day before measurement and 3 days prior respectively, were associated with reduced lung function in 8‐year‐olds. The pollen exposures were associated with decreases in FEV1 and FVC; however, the FEV1/FVC ratio was not affected. Effect modification by greenness was not observed due to loss of power.
Conclusions & Clinical Relevance
Airborne tree pollen of cypress, Casuarina and Pinus and not grass in some regions may be detrimental to childhood lung function.
To examine the impact of a prepregnancy very-low-energy diet (VLED) program on time to pregnancy in women with obesity.
Substudy of a two-arm parallel group randomized controlled trial.
Multiple ...tertiary care centers.
Women 18–38 years old with obesity (body mass index 30–55 kg/m2) and planning conception.
One hundred sixty-four normoglycemic women with body mass index 30–55 kg/m2, aged 18–38 years, and planning pregnancy were recruited through a social media platform for a two-arm randomized controlled trial. Women were allocated to a 12-week standard dietary intervention (SDI) or modified VLED. Completers of the intervention were observed for up to 48 weeks, and time to pregnancy was recorded.
The prespecified exploratory outcome for this substudy was time to pregnancy between the completion of the 12-week intervention and the date of conception.
Maternal weight loss at the end of the 12-week intervention was 3.1% in the SDI group and 11.9% in the VLED group. In completers of the 12-week intervention, time to pregnancy was significantly shorter in the women allocated to the VLED group than in the SDI group. Post hoc analysis showed that this difference in time to conception was particularly overt within 90 days of the intervention.
A VLED program that achieves substantial weight loss before conception reduces time to pregnancy compared with an SDI in women with obesity.
ACTRN12614001160628.
El tiempo en conseguir el embarazo después de un programa pregestacional, con una dieta muy baja en calorías en mujeres con obesidad: sub estudio de un ensayo controlado aleatorio.
Examinar el impacto de un programa de una dieta muy baja en calorías (VLED) en el tiempo para conseguir el embarazo en mujeres con obesidad.
Sub estudio de un ensayo controlado aleatorio de dos grupos en paralelo.
Múltiples centros de atención terciaria.
Mujeres de 18-38 años con obesidad (índice de masa corporal 30 a 55 kg / m2) y que han planificado concebir.
Se reclutaron ciento sesenta y cuatro mujeres normo glucémicas con índice de masa corporal de 30 a 55 kg / m2, de 18 a 38 años y que planeaban un embarazo, a través de una plataforma de redes sociales para un ensayo controlado aleatorio de dos grupos. Las mujeres fueron asignadas a una intervención dietética estándar (SDI) de 12 semanas o VLED modificado. Se observó a quienes completaron la intervención hasta 48 semanas y se registró el tiempo hasta conseguir el embarazo.
El resultado exploratorio preespecifico para este sub estudio fue el tiempo transcurrido hasta el embarazo, entre la finalización de la intervención a las 12 semanas y la fecha de la concepción.
La pérdida de peso materno al final de la intervención a las 12 semanas fue del 3,1% en el grupo de SDI y del 11,9% en el grupo de VLED. En aquellos casos que completaron la intervención de 12 semanas, el tiempo hasta el embarazo fue significativamente más corto en las mujeres asignadas al grupo VLED que en el grupo SDI. El análisis post hoc mostró que esta diferencia en el tiempo hasta la concepción fue particularmente evidente dentro de los 90 días posteriores a la intervención.
Un programa VLED en el que se logra una pérdida de peso sustancial antes de la concepción, reduce el tiempo en que se consigue el embarazo, en comparación con un SDI, en mujeres con obesidad.
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