tag:blogger.com,1999:blog-5548560205914833324.post5352861735806925735..comments2023-04-23T00:16:48.148+01:00Comments on Questioning Answers: Vitamins and autism: double-blind, placebo-controlled RCTPaul Whiteleyhttp://www.blogger.com/profile/14288851488012254897noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-5548560205914833324.post-31135511466081402042011-12-15T09:37:23.023+00:002011-12-15T09:37:23.023+00:00Thanks Harold. Another look at the paper seems to ...Thanks Harold. Another look at the paper seems to offer some guidance in this area. The dosage of both active & placebo supplement was gradually built up for all participants over the course of the first 21 days of study as a function of body weight. So days 1-4 included a sixth of the final dose, etc. up to 100% dose (for those that could tolerate their assigned med). This was done irrespective of whether experimental or placebo was assigned. Given that more children in the placebo group seemed to show adverse effects to their allocated intervention over the active intervention group gives a little weight to the proper way this was managed.<br />Protecting the double blind status is always an issue in these kinds of study where dose is not just given as a maximum from the start. The authors however seem to have gone to quite a lot of trouble to minimise the risk of the blindness being broken with regards to doing the same for both groups and other things like same flavouring, same packaging, etc for active and placebo. <br />As to the issue of study marshalls, this is not uncommon in such experimental design particularly in the newer 'adaptive' designs where for example, some way into a double-blind trial, you need to take a snapshot of where a trial stands.Paul Whiteleyhttps://www.blogger.com/profile/14288851488012254897noreply@blogger.comtag:blogger.com,1999:blog-5548560205914833324.post-84151174887165364472011-12-14T22:49:14.882+00:002011-12-14T22:49:14.882+00:00Interesting article and discussion. I look forward...Interesting article and discussion. I look forward to any follow up on the reply to Jon Brock's question. <br /><br />Forgive my ignorance but do study marshall's exist in other studies and can such a study marshall's participation save the double blind status of the test?Anonymoushttps://www.blogger.com/profile/05838571980003579163noreply@blogger.comtag:blogger.com,1999:blog-5548560205914833324.post-33885362866995634282011-12-14T15:27:12.986+00:002011-12-14T15:27:12.986+00:00Good question Jon and I need to perhaps look throu...Good question Jon and I need to perhaps look through the paper with greater assiduity to see if there is an answer. I suspect (and it is only that) that some kind of study marshall might have been involved as an independent observer.Paul Whiteleyhttps://www.blogger.com/profile/14288851488012254897noreply@blogger.comtag:blogger.com,1999:blog-5548560205914833324.post-43436394504539353312011-12-14T11:00:00.561+00:002011-12-14T11:00:00.561+00:00Genuine question: how do they maintain double blin...Genuine question: how do they maintain double blindness at the same time as adjusting the dose?<br /><br />"Temporary adverse effects were also reported during the early days of getting the dosages right but these seemed to be short-lived for the majority of participants."drbrocktagonhttps://www.blogger.com/profile/15225859145004971487noreply@blogger.com