Re: [tips] B vitamins, Alzheimer's, and telling the whole story
Stephen: Thanks for your analysis of the B vitamins and Alzheimer's study as reported. Query re cognitive impairment: Is it possible that previous studies showing some correlation between brain atrophy and the likelihood of developing Alzheimer's is relevant to the claims? http://brain.oxfordjournals.org/content/132/8/2026.short http://radiology.rsna.org/content/229/3/691.full Allen Esterson Former lecturer, Science Department Southwark College, London allenester...@compuserve.com http://www.esterson.org --- [tips] B vitamins, Alzheimer's, and telling the whole story sblack Thu, 09 Sep 2010 22:46:47 -0700 Our CTV television network, which prides itself in presenting the very latest in medical advances, adequate evidence or not, had another one tonight. A randomized controlled study which showed that a 2-year regimen of B vitamins in the elderly with mild cognitive impairment slows the rate of MRI-assessed brain atrophy. But funny, I said to my wife, there's no mention of cognitive improvement. Surely in a clinical study of this size and sophistication, not to mention expense, they would measure cognition before and after treatment. And if they did, wouldn't they be bound to mention the outcome? Think again. The study turns out to be Smith et al (2010). They took a battery of cognitive measures, all right, but there was nothing in the methods I could see noting that they took these measures after treatment as well as before. But apparently they did. Buried in a section labeled secondary outcomes was this statement Although the study was not powered to detect an effect of treatment on cognition (findings to be reported separately), in a post hoc analysis we noted that final cognitive test scores were correlated to rate of atrophy. My translation: We didn't find any difference between placebo and vitamin treatments in cognition, so we did what we could to put a positive spin on this, and also to forget about it. Anyway, if we had more subjects, we might have seen something (the not powered excuse). They provide a brief similar excuse (not powered to detect effects of treatment on cognitive test scores) in a later section titled Possible therapeutic implications. No data, of course. But curiously, if one goes to where they registered their trial before it began, they specified that in their study a primary outcome measure was Changes in performance on a variety of cognitive tests. Nothing there about not powered. See: http://www.controlled-trials.com/ISRCTN94410159/94410159 So it seems that in their haste to get out the good news (vitamins slow brain atrophy, which is indeed impressive), they somehow avoided providing the bad news (no detectable effect on cognition). Perhaps providing it would tend to dampen sales for the products for which Dr. Smith is listed as inventor with patents held by the University of Oxford and on which he could benefit financially (see competing interests). Stephen Smith, A. et al (2010). Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled tria. PLoS ONE, September 2010, v. 5, issue 9, e1244 Available here: http://tinyurl.com/Bvitamins-for-the-brain Stephen L. Black, Ph.D. Professor of Psychology, Emeritus Bishop's University e-mail: sblack at ubishops.ca 2600 College St. Sherbrooke QC J1M 1Z7 Canada --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5n=Tl=tipso=4702 or send a blank email to leave-4702-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
Re: [tips] B vitamins, Alzheimer's, and telling the whole story
And some continue to wonder why the public is losing its trust in science ... Miguel - Original Message - From: sbl...@ubishops.ca To: Teaching in the Psychological Sciences (TIPS) tips@fsulist.frostburg.edu Sent: Friday, September 10, 2010 1:46:15 AM Subject: [tips] B vitamins, Alzheimer's, and telling the whole story Our CTV television network, which prides itself in presenting the very latest in medical advances, adequate evidence or not, had another one tonight. A randomized controlled study which showed that a 2-year regimen of B vitamins in the elderly with mild cognitive impairment slows the rate of MRI-assessed brain atrophy. But funny, I said to my wife, there's no mention of cognitive improvement. Surely in a clinical study of this size and sophistication, not to mention expense, they would measure cognition before and after treatment. And if they did, wouldn't they be bound to mention the outcome? Think again. The study turns out to be Smith et al (2010). They took a battery of cognitive measures, all right, but there was nothing in the methods I could see noting that they took these measures after treatment as well as before. But apparently they did. Buried in a section labeled secondary outcomes was this statement Although the study was not powered to detect an effect of treatment on cognition (findings to be reported separately), in a post hoc analysis we noted that final cognitive test scores were correlated to rate of atrophy. My translation: We didn't find any difference between placebo and vitamin treatments in cognition, so we did what we could to put a positive spin on this, and also to forget about it. Anyway, if we had more subjects, we might have seen something (the not powered excuse). They provide a brief similar excuse (not powered to detect effects of treatment on cognitive test scores) in a later section titled Possible therapeutic implications. No data, of course. But curiously, if one goes to where they registered their trial before it began, they specified that in their study a primary outcome measure was Changes in performance on a variety of cognitive tests. Nothing there about not powered. See: http://www.controlled-trials.com/ISRCTN94410159/94410159 So it seems that in their haste to get out the good news (vitamins slow brain atrophy, which is indeed impressive), they somehow avoided providing the bad news (no detectable effect on cognition). Perhaps providing it would tend to dampen sales for the products for which Dr. Smith is listed as inventor with patents held by the University of Oxford and on which he could benefit financially (see competing interests). Stephen Smith, A. et al (2010). Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled tria. PLoS ONE, September 2010, v. 5, issue 9, e1244 Available here: http://tinyurl.com/Bvitamins-for-the-brain Stephen L. Black, Ph.D. Professor of Psychology, Emeritus Bishop's University e-mail: sblack at ubishops.ca 2600 College St. Sherbrooke QC J1M 1Z7 Canada --- --- You are currently subscribed to tips as: roig-rear...@comcast.net. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13482.917fac06d4daae681dabfe964ca8c74en=Tl=tipso=4700 or send a blank email to leave-4700-13482.917fac06d4daae681dabfe964ca8c...@fsulist.frostburg.edu --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5n=Tl=tipso=4704 or send a blank email to leave-4704-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
Re: [tips] B vitamins, Alzheimer's, and telling the whole story
On 10 Sep 2010 at 3:08, Allen Esterson wrote: Query re cognitive impairment: Is it possible that previous studies showing some correlation between brain atrophy and the likelihood of developing Alzheimer's is relevant to the claims? http://brain.oxfordjournals.org/content/132/8/2026.short http://radiology.rsna.org/content/229/3/691.full Interesting. But predictive is not the same as causes. And note that while they're happy to tell us about this encouraging- sounding correlation, they're somehow unable to provide a clear statement that they failed to find a difference between placebo and drug. The larger point is not that they can't be allowed some wiggle room. It may well be that their sample size was too small to detect a cognitive effect, or that they didn't continue the trial long enough (However, I understand that the prior evidence for B- vitamins for Alzheimer's is not encouraging.) No, the problem is that they instead buried this inconvenient finding. Imagine that they did find a positive effect. Would you find a similar reticence to mention it alongside the brain results? I won't hold my breath waiting for those promised negative findings to be reported separately. But even if they do appear, how much publicity do you think they will generate split off from the rest of the study? I now see that _New Scientist_ (NS) has also expressed reservations about the study, but I'd say they got it wrong. (See http://tinyurl.com/NewScientisttake ). NS complained that the sample was too small for the brain atrophy results. Actually, getting an effect with a small sample means the finding must be robust. Also, as we're not talking about a clinical drug effect, criticizing Smith et al by saying the absolute difference in atrophy size is small is not a persuasive criticism. But NS do incorrectly say that no cognitive tests were done. This makes my point. Smith et al's write-up seems to have misled them. Bottom line: If you say in advance that cognitive changes are one of your primary outcome measures (and you should), you'd better report 'em, even if you don't like the way they turned out. And even if doing so will dampen enthusiasm for buying said vitamins. Stephen Stephen L. Black, Ph.D. Professor of Psychology, Emeritus Bishop's University e-mail: sblack at ubishops.ca 2600 College St. Sherbrooke QC J1M 1Z7 Canada --- --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5n=Tl=tipso=4718 or send a blank email to leave-4718-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
[tips] TIPSTER OF THE WEEK
ANNETTE FUJAWSKI TAYLOR Michael omnicentric Sylvester,PhD Daytona Beach,Florida --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5n=Tl=tipso=4721 or send a blank email to leave-4721-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
[tips] Ronald Reagan 101 for Gainesville participants
TRUST BUT VERIFY! Michael omnicentric Sylvester,PhD Daytona Beach,Florida --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5n=Tl=tipso=4722 or send a blank email to leave-4722-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
Re: [tips] TIPSTER OF THE WEEK
Yo Fike: It's a 'K' On 9/10/2010 7:54 PM, michael sylvester wrote: ANNETTE FUJAWSKI TAYLOR Michael omnicentric Sylvester,PhD Daytona Beach,Florida --- --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5n=Tl=tipso=4723 or send a blank email to leave-4723-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
Re: [tips] B vitamins, Alzheimer's, and telling the whole story
Snake oil,snakoil,snake oil. Michael --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5n=Tl=tipso=4724 or send a blank email to leave-4724-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
