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Thread: FINALLY - Danish Twin study FORMALLY blown out of the water!

  1. #1
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    FINALLY - Danish Twin study FORMALLY blown out of the water!

    OMG. It's a penetrating glimpse into the obvious but it needed to be formally done.

    Please recall what I have said one million times about lay self-reports... garbage in - garbage out. GIGO. Nobody needs to be clairvoyant to see this coming.

    I don't expect to ever see another reference to this study in relation to downplaying the effects of genetics on scoliosis.

    Emphasis added to add emphasis LOL

    Concordance Rates of Adolescent Idiopathic Scoliosis in a Danish Twin Population.
    Simony, Ane; Carreon, Leah Y.; Hjmark, Karen; More
    Spine., Post Author Corrections: May 9, 2016
    Purchase Access Published Ahead-of-Print

    Study Design. Clinical, radiological and genetic determination of zygosity of twin pairs from the Danish Twin Registry who self-reported having Adolescent Idiopathic Scoliosis (AIS).

    Objective. To establish concordance rates of AIS.

    Summary of Background Data. The aetiology of and the true mode of inheritance of AIS remains unclear. Studies on concordance in twin pairs provide a basis for analysing the influence of genetic versus environmental factors. In 2007, using self-report of AIS from the Danish Twin Registry, concordance rates of 0.13 in monozygotic twins and 0.00 in dizygotic twins were reported.

    Methods. All 46,418 twins registered in the Danish Twin Registry born from 1931 to 1982 were sent a survey, which included questions about scoliosis. The survey was returned by 34,944 individuals (75.3%) representing 23,204 pairs. From this study, 548 individuals representing 274 complete twin pairs where at least one twin self-reported having scoliosis were invited to a clinical and radiological examination. Zygosity was established by genetic testing.

    Results. 182 individuals (33.2%) of the original cohort agreed to participate, 128 of whom had scoliosis by self-report. There were 91 twin pairs, where one or both twins had reported scoliosis and 36 individuals whose twin did not want to participate. Only 35 (27%) of the 128 participants with self-reported scoliosis had a clinically and radiologically confirmed curve. Calculating concordance in twins with Cobb angles greater than 10 degrees, we found that the pairwise concordance rate was 0.4 (0.10-0.70) for monozygotic and 0.05 (-0.05 -0.15) for dizygotic twins, p = 0.05, probandwise concordance was 0.45 (0.16-0.74) for monozygotic and 0.1 (-0.03-0.23) for dizygotic pairs.

    Conclusion. Concordance rates in a Danish twin population using genetic testing for zygosity are higher than previously reported using self-report. Although not statistically significant the differences in monozygotic and dizygotic pairs indicate genetic factors may be of importance for scoliosis.

    Level of Evidence: 3
    Last edited by Pooka1; 06-18-2016 at 12:47 PM.
    Sharon, mother of identical twin girls with scoliosis

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    If something doesn't make sense then it probably isn't true.

    Now we need someone to review the Swedish twin study which also contained lay self reporting.

    I am not clear on why lay self reporting is being published at all. The Danish study is often mentioned just to be shot down because it doesn't agree with results from scientifically rigorous studies. It would be easier if it was never published.
    Last edited by Pooka1; 06-18-2016 at 05:53 PM.
    Sharon, mother of identical twin girls with scoliosis

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    "We are all African."

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    73% who reported scoliosis didn't have any curves. That places everything self-reported into question.
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    Quote Originally Posted by LindaRacine View Post
    73% who reported scoliosis didn't have any curves. That places everything self-reported into question.
    Understatement of the century.

    This study reeked of being garbage. It should be retracted.

    Actually I hope the original journal is alerted to this and retracts it. I will send it to Retractionwatch to look for it.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
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    "We are all African."

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    I guess that proves that 73% of people “think” they have scoliosis.......and for “attention” needs, I guess this works...

    People need attention.....its a hell of a way to do it, but your much better off with a Chewbacca mask..... Its worth every penny.

    Sometimes, and I will admit, usually when camping, around the campfire late at night, the mask goes on.

    And when those bears see a fused wookie stoking the fire..... they RUN for their lives. Ha ha ha

    Ed
    49 yr old male, now 58, the new 53...
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    Bending and twisting pics after full fusion
    http://www.scoliosis.org/forum/showt...on.&highlight=

    My x-rays
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    http://www.scoliosis.org/forum/attac...3&d=1228779258

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    Quote Originally Posted by titaniumed View Post
    I guess that proves that 73% of people “think” they have scoliosis.......and for “attention” needs, I guess this works...

    People need attention.....its a hell of a way to do it, but your much better off with a Chewbacca mask..... Its worth every penny.

    Sometimes, and I will admit, usually when camping, around the campfire late at night, the mask goes on.

    And when those bears see a fused wookie stoking the fire..... they RUN for their lives. Ha ha ha

    Ed
    LOL Ed!

    I think they were just honestly mistaken. Hypochondria can't be that prevalent. It almost seems like a simple spreadsheet error because I find it hard to believe that many people even know what scoliosis is and were mistaken about having it.

    There was an obvious spreadsheet type error in another paper we discussed about the prevalence of various diseases and they inadvertently left scoliosis off a table though it was mentioned in the text as if it was in the table.

    Anyway, I am going to get the paper. I never saw the 73% mis-identification coming but I am betting the zygosity claims are riddled with nonsense. There is an undercurrent of denying identicalness for some reason... maybe it is just not understanding how different identical twins can be. This original study put concordance between identical twins at about 13% as I recall and concordance between fraternal twins at zero. The actual numbers are about 70 - 90% for identical and about 30% for fraternal. These results disagree so much with every rigorous study out there that you can bet your house there were false. Someone should write a paper on why people are allowed to publish lay self reports in the scientific literature. LOL

    Edited to add... there is more potential nonsense with the original study. If they surveyed some twins who claimed they did not have scoliosis, I am very confident they would find many who did. If that is true, the actual concordance rate between twins of both types might more closely match the rates determined from rigorous studies. As it stands now, they just assessed the false positive rate. They need to also assess the false negative rate which might be even higher. The original study is a symphony of wasted journal space. It is so bad that it should be retracted in my opinion.
    Last edited by Pooka1; 06-19-2016 at 08:42 AM.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Quote Originally Posted by Pooka1 View Post
    Someone should write a paper on why people are allowed to publish lay self reports in the scientific literature.
    Sharon, maybe its time for a motivational or demotivational poster of Chewbacca carrying C3P0 in parts..... This sort of thing can infuse accountability amongst those that make spreadsheet errors....(smiley face)

    Now, what would the caption say?....

    See attachment below...

    Ed
    Attached Images Attached Images
    49 yr old male, now 58, the new 53...
    Pre surgery curves C12,T70,L70
    ALIF/PLIF T2-Pelvis 01/29/08, 01/31/08 7" pelvic anchors BMP
    Dr Brett Menmuir St Marys Hospital Reno,Nevada

    Bending and twisting pics after full fusion
    http://www.scoliosis.org/forum/showt...on.&highlight=

    My x-rays
    http://www.scoliosis.org/forum/attac...2&d=1228779214

    http://www.scoliosis.org/forum/attac...3&d=1228779258

  8. #8
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    LOL Ed!

    Let s/he who is without simple spreadsheet error cast the first retraction order...

    LOL
    Last edited by Pooka1; 06-19-2016 at 02:30 PM.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    I think we can estimate the false negative rate in the Danish Twins Study from the information given for false positive.

    The original study found 1.05% of the twins reported scoliosis. I pointed out that this was a problem because the group was presumably large enough to get closer to the 3% incidence that is commonly mentioned.

    Now we know from the new study that 73% of the 1.05% was false positive. So the actual incidence based on the reporting and correcting for false positive is 0.23 * 0.0105 = 0.0024 = 0.24%.

    So based on their data and considering the false positive rate, the incidence of scoliosis in the large twins group is 0.24%. But the actual number is closer to 3%. So the false negative rate is (3.0 - 0.24)/3.0 = 92%.

    If that math is correct then the false positive rate is 73% and the false negative rate is about 92%. If that doesn't define nonsense I am not sure what does.
    Last edited by Pooka1; 06-21-2016 at 05:29 PM.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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