Reproducibility, power and validity of visual analogue scales in assessment of appetite sensations in single test meal studies.
TL;DR: VAS scores are reliable for appetite research and do not seem to be influenced by prior diet standardization, however, consideration should be given to the specific parameters being measured, their sensitivity and study power.
Abstract: OBJECTIVE: To examine reproducibility and validity of visual analogue scales (VAS) for measurement of appetite sensations, with and without a diet standardization prior to the test days DESIGN: On two different test days the subjects recorded their appetite sensations before breakfast and every 30 min during the 45 h postprandial period under exactly the same conditions SUBJECTS: 55 healthy men (age 256±06 y, BMI 226±03 kg/m2) MEASUREMENTS: VAS were used to record hunger, satiety, fullness, prospective food consumption, desire to eat something fatty, salty, sweet or savoury, and palatability of the meals Subsequently an ad libitum lunch was served and energy intake was recorded Reproducibility was assessed by the coefficient of repeatability (CR) of fasting, mean 45 h and peak/nadir values RESULTS: CRs (range 20–61 mm) were larger for fasting and peak/nadir values compared with mean 45 h values No parameter seemed to be improved by diet standardization Using a paired design and a study power of 08, a difference of 10 mm on fasting and 5 mm on mean 45 h ratings can be detected with 18 subjects When using desires to eat specific types of food or an unpaired design, more subjects are needed due to considerable variation The best correlations of validity were found between 45 h mean VAS of the appetite parameters and subsequent energy intake (r=±050−053, P<0001) CONCLUSION: VAS scores are reliable for appetite research and do not seem to be influenced by prior diet standardization However, consideration should be given to the specific parameters being measured, their sensitivity and study power
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TL;DR: Low-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize, and improved lipid-related risk factors and fasting insulin levels.
Abstract: BackgroundThe possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year. MethodsWe randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content. ResultsAt 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years...
1,715 citations
TL;DR: Glucagon-like peptide 1 (GLP-1) could be a new treatment for type 2 diabetes, though further investigation of the long-term effects of this peptide hormone is needed.
1,353 citations
TL;DR: Efforts to increase dietary fiber in individuals consuming <25 g/day may help to decrease the currently high national prevalence of obesity.
Abstract: The influence of dietary fiber on energy regulation remains controversial. This review summarizes published studies on the effects of dietary fiber on hunger, satiety, energy intake, and body composition in healthy individuals. Under conditions of fixed energy intake, the majority of studies indicate that an increase in either soluble or insoluble fiber intake increases postmeal satiety and decreases subsequent hunger. When energy intake is ad libitum, mean values for published studies indicate that consumption of an additional 14 g/day fiber for >2 days is associated with a 10% decrease in energy intake and body weight loss of 1.9 kg over 3.8 months. Furthermore, obese individuals may exhibit a greater suppression of energy intake and body weight loss (mean energy intake in all studies was reduced to 82% by higher fiber intake in overweight/obese people versus 94% in lean people; body weight loss was 2.4 kg versus 0.8 kg). These amounts are very similar to the mean changes in energy intake and body weight changes observed when dietary fat content is lowered from 38% to 24% of energy intake in controlled studies of nonobese and obese subjects. The observed changes in energy intake and body weight occur both when the fiber is from naturally high-fiber foods and when it is from a fiber supplement. In view of the fact that mean dietary fiber intake in the United States is currently only 15 g/day (i.e., approximately half the American Heart Association recommendation of 25-30 g/day), efforts to increase dietary fiber in individuals consuming <25 g/day may help to decrease the currently high national prevalence of obesity.
1,001 citations
TL;DR: It is demonstrated for the first time that increasing colonic propionate prevents weight gain in overweight adult humans.
Abstract: Objective The colonic microbiota ferment dietary fibres, producing short chain fatty acids. Recent evidence suggests that the short chain fatty acid propionate may play an important role in appetite regulation. We hypothesised that colonic delivery of propionate would increase peptide YY (PYY) and glucagon like peptide-1 (GLP-1) secretion in humans, and reduce energy intake and weight gain in overweight adults. Design To investigate whether propionate promotes PYY and GLP-1 secretion, a primary cultured human colonic cell model was developed. To deliver propionate specifically to the colon, we developed a novel inulin-propionate ester. An acute randomised, controlled cross-over study was used to assess the effects of this inulin-propionate ester on energy intake and plasma PYY and GLP-1 concentrations. The long-term effects of inulin-propionate ester on weight gain were subsequently assessed in a randomised, controlled 24-week study involving 60 overweight adults. Results Propionate significantly stimulated the release of PYY and GLP-1 from human colonic cells. Acute ingestion of 10 g inulin-propionate ester significantly increased postprandial plasma PYY and GLP-1 and reduced energy intake. Over 24 weeks, 10 g/day inulin-propionate ester supplementation significantly reduced weight gain, intra-abdominal adipose tissue distribution, intrahepatocellular lipid content and prevented the deterioration in insulin sensitivity observed in the inulin-control group. Conclusions These data demonstrate for the first time that increasing colonic propionate prevents weight gain in overweight adult humans. Trial registration number NCT00750438.
898 citations
TL;DR: This report describes a set of scientific procedures used to assess the impact of foods and food ingredients on the expression of appetite (psychological and behavioural), and allows the evaluation of the strength of health claims about the effects of foods on appetite.
Abstract: This report describes a set of scientific procedures used to assess the impact of foods and food ingredients on the expression of appetite (psychological and behavioural). An overarching priority has been to enable potential evaluators of health claims about foods to identify justified claims and to exclude claims that are not supported by scientific evidence for the effect cited. This priority follows precisely from the principles set down in the PASSCLAIM report. The report allows the evaluation of the strength of health claims, about the effects of foods on appetite, which can be sustained on the basis of the commonly used scientific designs and experimental procedures. The report includes different designs for assessing effects on satiation as opposed to satiety, detailed coverage of the extent to which a change in hunger can stand alone as a measure of appetite control and an extensive discussion of the statistical procedures appropriate for handling data in this field of research. Because research in this area is continually evolving, new improved methodologies may emerge over time and will need to be incorporated into the framework. One main objective of the report has been to produce guidance on good practice in carrying out appetite research, and not to set down a series of commandments that must be followed.
858 citations
Cites background from "Reproducibility, power and validity..."
...Depending upon the assessment criterion, the line scales used most commonly in appetite research (Table 1) have been found to have variable repeat-reliability with individual subjects under controlled laboratory conditions, but generally good repeat-reliability with regard to group mean data and comparisons of specific foods (71,76,78,79,86,87), even over several months or years (87)....
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...perhaps just statistical significance) (86)....
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...(86) indicate that 8–35 subjects would be required to identify a 10-mm (10%) difference in 4....
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...A 10% difference is typically also seen as ‘a reasonable and realistic difference’ (86)....
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References
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TL;DR: An alternative approach, based on graphical techniques and simple calculations, is described, together with the relation between this analysis and the assessment of repeatability.
43,884 citations
Book•
15 Jun 2006
TL;DR: Practical Statistics for Medical Research is a problem-based text for medical researchers, medical students, and others in the medical arena who need to use statistics but have no specialized mathematics background.
Abstract: Most medical researchers, whether clinical or non-clinical, receive some background in statistics as undergraduates. However, it is most often brief, a long time ago, and largely forgotten by the time it is needed. Furthermore, many introductory texts fall short of adequately explaining the underlying concepts of statistics, and often are divorced from the reality of conducting and assessing medical research.
Practical Statistics for Medical Research is a problem-based text for medical researchers, medical students, and others in the medical arena who need to use statistics but have no specialized mathematics background.
The author draws on twenty years of experience as a consulting medical statistician to provide clear explanations to key statistical concepts, with a firm emphasis on practical aspects of designing and analyzing medical research. The text gives special attention to the presentation and interpretation of results and the many real problems that arise in medical research
17,322 citations
11,536 citations
TL;DR: Visual analogue scales (VAS) of sensory intensity and affective magnitude were validated as ratio scale measures for both chronic and experimental pain, demonstrating the valid use of VAS for the measurement of and comparison between chronic pain and experimental heat pain.
Abstract: Visual analogue scales (VAS) of sensory intensity and affective magnitude were validated as ratio scale measures for both chronic and experimental pain. Chronic pain patients and healthy volunteers made VAS sensory and affective responses to 6 noxious thermal stimuli (43, 45, 47, 48, 49 and 51 degrees C) applied for 5 sec to the forearm by a contact thermode. Sensory VAS and affective VAS responses to these temperatures yielded power functions with exponents 2.1 and 3.8, respectively; these functions were similar for pain patients and for volunteers. The power functions were predictive of estimated ratios of sensation or affect produced by pairs of standard temperatures (e.g. 47 and 49 degrees C), thereby providing direct evidence for ratio scaling properties of VAS. Vas sensory intensity responses to experimental pain, VAS sensory intensity responses to different levels of chronic pain, and direct temperature (experimental pain) matches to 3 levels of chronic pain were all internally consistent, thereby demonstrating the valid use of VAS for the measurement of and comparison between chronic pain and experimental heat pain.
3,440 citations
TL;DR: A linear analogue for rating pain with 10, 15 and 20 cm lines is significantly less variable than a 5 cm line and the linear analogue rating of a constant pain stimulus is reproducible and changes in rating are likely to be real changes of opinion.
Abstract: A linear analogue for rating pain with 10, 15 and 20 cm lines is significantly less variable than a 5 cm line (mean error of 15 cm line is 0-19%, 95% confidence limits for the group +/- 2% and an inood correlation between repeated ratins of a recalled pain distant in time. The variance of the rating is significantly less than the repeated rating of a random mark. The linear analogue rating of a constant pain stimulus is reproducible and changes in rating are likely to be real changes of opinion. Pethidine 150 mg intramuscularly had no significant effect, tested 30 minutes after the administration, on the accuracy or reproducibility of the analogue rating. A linear analogue seems a suitable method of recording the patient's opion of a severe pain such as that of labour.
1,232 citations