On Fri, 17 Aug 2012 15:13:23 -0700, Carol DeVolder wrote: >Thanks Beth, I should have done that too. I've been sitting here >summarizing it. Duh. >I like the compliance rate as well as the fact that Mars, Inc. funded the >study and supplied the cocoa. >What I really like about this is that this study, as Medscape portrays it >anyway, is easily understood in terms of IVs and DVs and other variables. >I'll probably use it for class for my students to critique and discuss.. >Thanks again!
I guess that I really don't have to say this but just as a reminder, one should not rely upon popular media accounts of a research study and should get the original source. I don't have to point out that a popular media account may oversimplify a study and/or not report all relevant information. For example, it says below that Mars supplied the cocoa but consider the following quote from the article: |The HF and IF drink mixes were made with a flavanol-rich cocoa powder |(Cocoapro processed cocoa powder; Mars Inc), whereas the LF drink |was made with a highly processed, alkalized cocoa powder. Now, I don't know food chemistry but I would assume that the High Flavanol (HF) cocoa differs from the Intermediate Flavanol (IF) cocoa only in levels of flavanol, if the Mars company did it right. But did the Mars company provide the Low Flavanol (LF) cocoa? Why do they say "highly processed alkalized cocoa powder"? Does this mean that it differed from the other cocoas not only in cocoa level but also alkaline level? How else might it have differed from the other cocoas? What effect might those differences have? And I'm not a neuropsychologist, but I do wonder about the measures that were used to measure Mild Cognitive Impairment (MCI). I understand using Mini Mental State Examination, (MMSE) because it is a standard neurological instrument. And this is what is said about the MMSE: |Mini Mental State Examination score did not significantly change in |relation to the 3 different treatments during the study period (P=0.13; |Table 1). Now, one has to remember that the design being used is a two-way mixed design with the between-subject factor being the 3 cocoa groups and the within-subject factor being the 2 times of measurement (i.e., baseline vs 8 weeks). A mixed repeated measures ANOVA would give a main effect for groups and main effect for time of measurement and the two-way group by time interaction. Their presentation of tests is a little confusing but in the quote above the authors are referring to the two-way interaction, that is, level of MMSE was the same for the three group over time. They don't explicitly say that there is a nonsignificant main effect for groups nor do they say that they (apparently) had a significant main effect for time of measurement, that is, all 3 groups had higher MMSE scores at 8 weeks relative to baseline. No cocoa effect. I won't go into detail about the other measures of MCI reported but do show differences consistent with a cocoa effect. But I wonder (a) why were these particular measures used and (b) did they use other measures that provided nonsignificant results which were not reported. The "Limitations" section of the paper is intriguing; quoting: |First, because standard MCI criteria do not define optimal |tests to establish cognitive performance in subjects with MCI (22), |cognitive testing was performed using a battery of well-validated, |standardized, and widely used neuropsychological tests exploring |only some aspects of the complex cognitive dysfunction in subjects |with MCI (1,2). One wonders if all of the results for all of the tests in the battery are reported, just out of curiosity. Finally, I do have some experience with data analysis and I would suggest that one look at the results carefully. Given the mixed design one might think that the result of greatest interest would be the two-way interaction and what form it has (the researchers appear to have some planned comparison separate from the ANOVA they report). The interactions would be good to graph since the expected pattern is a "fan", that is, all group means should cluster at baseline and have a separation at 8 weeks. I think that it is fairly easy to visually imagine this pattern. One would have to because the don't provide any figures, just tables. And their Table 1 which reports F-values and descriptive statistics for the measures seems a little confusing. Instead of reporting F-values for main effects of groups and time, individual F-values are given for each level of the factor (it could be a simple effects analysis but the authors do not refer to it as such). Why this is done is unclear. Anyway, I'm rambling, remember, always get the original sources, read it carefully, and be a little suspicious when the second author is an employee of the Mars company -- and ask why they didn't use grape juice instead (see page 799, second paragraph of the Discussion). -Mike Palij New York University [email protected] On Fri, Aug 17, 2012 at 4:53 PM, Beth Benoit wrote: > Here it is...free registration, so I don't feel I'm stepping on any toes. > > From Medscape Medical News <http://www.medscape.com/news> > > Neurology<http://www.medscape.com/index/section_10172_0> Cocoa > Can Boost Cognitive Function > > Megan Brooks > >August 14, 2012 — A new study hints that regular consumption of cocoa > flavanol might improve cognitive function in older adults with mild > cognitive impairment (MCI), perhaps by improving glucose-insulin metabolism. > > "Given the global rise in cognitive disorders due to the 'graying' of > populations in Western countries, our findings provide encouraging evidence > that consuming cocoa flavanols could represent a fascinating new tool for > preserving/improving cognitive function during senescence," first author > Giovambattista Desideri, MD, director of the Geriatric Division, Department > of Life, Health and Environmental Sciences, University of L'Aquila in > Italy, told*Medscape Medical News*. > Dr. Giovambattista Desideri > > The study was published > online<http://hyper.ahajournals.org/content/early/2012/08/14/HYPERTENSIONAHA.112.193060.abstract> > August > 14 in *Hypertension*. It was funded by Mars Inc, a maker of chocolate > products; the company also provided the standardized cocoa drinks used in > the trial. > > *Findings "Intriguing"* > > "There is great interest in identifying nutritional factors that could > potentially delay or prevent conversion of MCI to dementia," Mary Ann > Johnson, PhD, national spokesperson for the American Society of Nutrition > (ASN), who was not involved in the study, told*Medscape Medical News*. > > What makes this study novel, she said, is that it is a randomized > controlled trial in people with MCI, it employed well-known cognitive > tests, and it used 3 levels of cocoa flavanols: low, medium, and high. > > "Both the medium and high levels conferred some benefits to cognition, > insulin resistance, and blood pressure. Poor cognition, poor insulin > resistance, high blood pressure, and other cardiovascular risk factors have > all been linked to dementia," Dr. Johnson said. > > "These are intriguing findings that should be followed up with additional > research studies to confirm these findings for cocoa," added Dr. Johnson, > who is from the Department of Foods and Nutrition, College of Family and > Consumer Sciences at the University of Georgia in Athens. > > *More Is Better?* > > Based on prior studies, intake of flavonoids may be associated with a > decreased risk for incident dementia, a lower prevalence of cognitive > impairment, and better cognitive evolution over 10 years in aging adults, > the authors note. > > To investigate further, Dr. Desideri and colleagues recruited 90 elderly > individuals with MCI into the Cocoa, Cognition and Aging (CoCoA) Study. > They were randomly assigned to consume once daily for 8 weeks a drink > containing 1 of 3 levels of cocoa flavanols: 990 mg, the high flavanol (HF) > group; 520 mg, the intermediate flavanol (IF) group; or 45 mg, the low > flavanol (LF) group. > > Overall compliance was good — 99.6% at week 4 and 99.4% at week 8, with no > between-group differences. > > The team assessed cognitive function using the Mini–Mental State > Examination (MMSE), the Trail Making Test A (TMT A) and B (TMT B), and a > verbal fluency test. Baseline performances on these 3 tests were similar. > > During the study period, the researchers did not see any significant > changes in MMSE scores in relation to group assignment. > > However, the time needed to complete the TMT A did change significantly > during the study period (*P* < .0001), with significant reductions > observed in participants in the HF group (-14.3 seconds; *P* < .0001) and > IF group (-8.8 seconds; *P* < .0001) but not in those in the LF group > (+1.1 seconds; *P* = .65). > > The results were similar for the TMT B test, with significant reductions > in the time needed to complete the test seen in the HF and IF groups (-29.2 > and -22.8 seconds, respectively; for both, *P* < .0001) but not in the LF > group (+3.8 seconds; *P* = .21). > > As a result, TMT A and B scores at the end of follow-up were significantly > (*P* < .05) better in the HF and IF groups than in the LF group, the > authors note. > > Additionally, they say verbal fluency test scores significantly improved ( > *P* < .0001) during the study, with improvements seen in the HF group > (+8.0 words per 60 seconds; *P* < .0001) and IF group (+5.1 words per 60 > seconds; *P* < .0001) and, to a lesser extent, in the LF group (+1.2 > words per 60 seconds; *P* < .014). > > The improvement of verbal fluency test score was significantly greater in > HF participants than in those assigned to the LF group (*P* < .05). > > Baseline blood pressure and metabolic parameters were similar in the 3 > groups, but with treatment, HF and IF groups experienced a decrease in > insulin resistance, blood pressure, and lipid peroxidation. > > *Insulin Resistance* > > Dr. Desideri and colleagues report that changes in homeostasis model > assessment–insulin resistance (HOMA-IR) were the main determinants of > change in cognitive function, accounting for roughly 40% of composite z > score variability throughout the study period (*P* < .0001). > > Changes in systolic blood pressure levels and plasma isoprostane > concentrations accounted for only 2% and 7% of cognitive improvement, > respectively, throughout the study period. > > "Our data suggest that regular cocoa flavanol consumption, in the context > of a calorie-controlled and nutritionally balanced diet, might represent an > effective strategy in preserving brain and cardiovascular health and > function," Dr. Desideri concluded. "Obviously, larger studies are needed to > validate our findings." > > The researchers caution that the intervention lasted only 2 months; > therefore, the extent of the cognitive benefits and their duration, as well > as their impact on a clinical course of MCI, remain to be established. > > It is also unclear whether the observed benefits in neurocognition are a > direct consequence of cocoa flavanols themselves or a secondary effect > related to general improvements in cardiovascular function or health. > > Finally, the study team points out that the participants in the study were > generally in good health and were free of cardiovascular disease and > therefore may not be completely representative of all individuals with MCI. > > *The study was supported by a grant from Mars Inc, which also supplied > the standardized powdered cocoa drinks used in the study. One author is an > employee of Mars Inc. A complete list of author disclosures is given in the > original article*. > > *Hypertension.* Published online August 14, 2012. > Abstract<http://hyper.ahajournals.org/content/early/2012/08/14/HYPERTENSIONAHA.112.193060.abstract> > > On Fri, Aug 17, 2012 at 5:42 PM, Paul C Bernhardt < > [email protected]> wrote: > >> >> >> >> >> >> >> Can you provide a summary? Not all of us can see the article on MedScape. >> >> Paul >> >> On Aug 17, 2012, at 4:28 PM, Carol DeVolder wrote: >> >> >> >> >> I'm not surprised at the high compliance rate. >> http://www.medscape.com/viewarticle/769112?src=mpnews%3Fsrc%3Dstfb --- You are currently subscribed to tips as: [email protected]. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=19814 or send a blank email to leave-19814-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
