Revenge of teh Chubby Virus!

I know you all have seen the headlines. Again.

More evidence links a virus to obesity, this time in children‎
Study: Children Exposed to Adenovirus-36 Likely to Get Obese‎
Virus Is Linked To Obesity
Can a Cold Lead to Childhood Obesity?

Adenovirus 36 and Obesity in Children and Adolescents

Adenoviruses are ubiquitous. Weve all been infected with lots of them (gets to be a problem when making gene therapy vectors). The older you are, the more likely you have been exposed to the different kinds of adenovirus, to the point where if you are an adult reading this, you probably have antibodies to serotypes 1, 2, 5, and/or 6 (depending on where you live).

Thus older children are more likely to have been exposed to any adenovirus, including Ad-36. If your ‘obese’ group of children is 63% kids aged 15-18, and your ‘healthy weight’ group is only 17% 15-18, I am not shocked at all that antibodies to Ad-36 is correlated with obesity. I bet you could have picked any other adenovirus serotype and found the same correlation. But they didnt look.

William M. Briggs gets it. I dunno the dude. Statistician. But he gets it. *thumbs-up*

From a virologists perspective, there are putative, plausible mechanisms for how Ad-36 could actually play a role in obesity. Those reasonings require ongoing replication. If you have an actively replicating virus, you should have higher titer antibodies. This study did not simply ask ‘Are there Ad-36 antibodies? YES/NO’ They used a protocol that could tell you the titer (concentration) of antibodies in samples. Yet no titer was reported, or distribution of titer. Were they all positive in only the second dilution, implying that the children had been exposed, at some point, but the virus was loooooong gone (thus cutting any current hypotheses for how Ad-36 could cause obesity off at the knees)? Or were they all positive out to the last dilution, implying current, ongoing infection? Or was there a mix? I dunno. Not reported… even though the measurements were made.

*blink*

Or maybe the people with persistent Ad-36 infections make Ad-36 antibodies, but they are ineffective and non-neutralizing. Or maybe people with persistent Ad-36 infections dont make Ad-36 antibodies at all (some bias form an earlier infection preventing the generation of true Ad-36 antibodies, like antigenic sin). They would not ‘see’ these antibodies in the assay used. Maybe the opposite conclusion is true– people persistent Ad-36 infections due to non-neutralizing antibodies are ‘protected’ from obesity. O.o They dunno. Didnt look.

If you really want to connect Ad-36 to obesity, you have to look for the virus. Not antibodies to the virus. Took me about 0.5 seconds of searching PubMed to find numerous protocols for detecting adenovirus genome.

*blink*

Comments

  1. #1 Charl
    September 22, 2010

    From the WPI/Mikovits school of virology, then.

  2. #2 ERV
    September 22, 2010
  3. #3 Kemanorel
    September 22, 2010

    I think the obesity problem is much more related to this:

    http://www.youtube.com/watch?v=UtwMRnc_oU0

  4. #4 Bgin
    September 22, 2010

    And the Ruscetti, Silverman, Klein school.

  5. #5 ERV
    September 22, 2010

    Pick a handle, CAT/Bgin.

  6. #6 daedalus2u
    September 22, 2010

    I wonder how many different viruses they looked for, and was Ad 36 the only one that showed a result that was publishable?

  7. #7 DevelopingGeneticist
    September 22, 2010

    If your ‘obese’ group of children is 63% kids aged 15-18, and your ‘healthy weight’ group is only 17% 15-18, I am not shocked at all that antibodies to Ad-36 is correlated with obesity.

    Actually, ERV, the percentages you’ve referred to are the age distributions for the Ad-32 negative vs positive groups, NOT obese vs healthy.

    They haven’t given any numbers for the age distributions of the “obese” and “healthy” groups – which is insane. What a strange little paper.

  8. #8 ERV
    September 22, 2010

    Second screw up in as many posts.

    *facepalm*

    Thanks, DG!

  9. #9 BAllanJ
    September 22, 2010

    Of course, if the virus did cause weight gain the weight wouldn’t suddenly dissappear the day the infection cleared up, so I’m not sure how you need a correlation between current weight and current infection.

  10. #10 theshortearedowl
    September 23, 2010

    I’m not sure how you need a correlation between current weight and current infection.

    As I understand it, for a virus to cause significant weight gain in the long term, it would have to be a persistent infection. No one gets obese over the course of a 2 week cold.

  11. #11 Anonymous
    September 24, 2010

    From the article, I don’t see any causal relationship between Adv-36 and obesity. I think the conclussion “virus making us fat” is too early to say.

  12. #12 TOT
    September 25, 2010

    Is there any need to pick a handle?

  13. #13 Charl
    April 6, 2011

    Apparently, a lack Helicobacter pylori is making people fat… http://www.sciencemag.org/content/332/6025/32.full.pdf

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