BBC Article: Bike Now to Avoid Senility

Elisa Francesca Roselli said:

http://news.bbc.co.uk/2/hi/health/4304822.stm

Yet another article filled with bad science. I don't doubt there is a
correllation between exercise and lowered risk of dementia. But they
failed to establish a true cause and effect relationship. This is a
typical ecological fallacy.

The true cause of the lowered risk may be eating habits. Perhaps it is
more frequent washing (exercisers get stinky and probably wash more
often). Maybe it is that exercisers have a lower exposure to chemical
propellants because they are less concerned with their state of their
hair - it's going to get messed up anyway, right? The point is that
there are a lot of differences between exercisers and non-exercisers
that are not accounted for in the article. If the researchers did
attempt to control for this, it certainly isn't presented in the bbc
article. If so, then this is just another case of the public press
butchering good science because they don't know how to report it
properly.

Here's a good article on ecological fallacy:
http://www.stanford.edu/class/ed260/freedman549.pdf

-Buck

Didn't look like bad science to me - anyway the science is in the
research paper whereas this is just a journalistic report. It would
seem that the conclusions are hedged with 'mays' and 'mights' and the
conclusion is that 'more research is needed'. You don't need to prove a
cause and effect to establish that something may be hazardous or
beneficial.
Anyway I'm going to keep on pedalling even if it is too late in my
case.

cheers

Jacob

Quoted message said:

Didn't look like bad science to me - anyway the science is in the
research paper whereas this is just a journalistic report. It would
seem that the conclusions are hedged with 'mays' and 'mights' and the
conclusion is that 'more research is needed'. You don't need to prove a
cause and effect to establish that something may be hazardous or
beneficial.

Agreed.

I understand Buck's point, but there's no need to put the article down
so harshly. One might say "Hmmm. Perhaps this needs further study."
But if we immediately reject every study (or every report of a study)
that doesn't account for every confounding variable, science will slow
to a crawl.

I think the way these things generally go is this: Someone notices a
correlation like the one mentioned in the article, and publishes it.
Someone else notes what Buck did - that there may be other factors at
work - and questions it. A third team may refine the work done by the
first, controlling other variables in various ways. That process is
repeated, with new knowledge gained each time.

At some point, there's enough confidence in the knowledge to recommend
for or against the original idea, of course taking benefits and
detriments into account.

On this particular issue, I figure the benefits of exercise are many.
This _may_ be just one more. The detriments are few. I see no harm in
mentioning this possible benefit, at least until it's disproven.

- Frank Krygowski

Buck said:

Elisa Francesca Roselli said:

http://news.bbc.co.uk/2/hi/health/4304822.stm

Yet another article filled with bad science. I don't doubt there is a
correllation between exercise and lowered risk of dementia. But they
failed to establish a true cause and effect relationship. This is a
typical ecological fallacy.

Have you read the paper yet? It is interesting though my quick skim
suggests some worries about the stats. I'll have to go back and look
more closely.

Quoted message said:

The true cause of the lowered risk may be eating habits. Perhaps it is
more frequent washing (exercisers get stinky and probably wash more
often). Maybe it is that exercisers have a lower exposure to chemical
propellants because they are less concerned with their state of their
hair - it's going to get messed up anyway, right? The point is that
there are a lot of differences between exercisers and non-exercisers
that are not accounted for in the article.

Try the Lancet Neurology article. They appear to be controlling for a
few variables of interest.

Quoted message said:

From the Lancet Neurology pre-pub

"In brief, the baseline survey procedures included a self-administered
questionnaire on health behaviour, health status, and medical history.
Participants' blood pressure, height, and weight were measured, and
body-mass index (BMI) was calculated. A venous blood sample was taken
to determine serum cholesterol concentrations.13 In addition, the
presence of various locomotor disorders was determined. [...]

If the researchers did

Quoted message said:

attempt to control for this, it certainly isn't presented in the bbc
article. If so, then this is just another case of the public press
butchering good science because they don't know how to report it
properly.

Here's a good article on ecological fallacy:
http://www.stanford.edu/class/ed260/freedman549.pdf

-Buck>

John Kane
Kingston ON

General Systems Theory Beginning with Wholes

General Systems Theory Beginning with Wholes

Dunno why you didn't just go to the original Lancet article to see if
it's legit, but through the magic of the internet, here's a link for
those who are interested:

http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6X3F-4H80T19-1-3&_cdi=7297&_user=1493582&_orig=search&_coverDate=10%2F04%2F2005&_sk=999999999&view=c&wchp=dGLbVzz-zSkzV&md5=f5cd3c1ee23fb21d1cabef28ea8aab36&ie=/sdarticle.pdf

-JR

SlowRider said:

Dunno why you didn't just go to the original Lancet article to see if
it's legit, but through the magic of the internet, here's a link for
those who are interested:

Thanks. Going directly via the Lancet requires payment. That seems a bit
silly if its available elsewhere for free!

Colin

Colin Blackburn said:

SlowRider said:

Dunno why you didn't just go to the original Lancet article to see if
it's legit, but through the magic of the internet, here's a link for
those who are interested:

Thanks. Going directly via the Lancet requires payment. That seems a bit
silly if its available elsewhere for free!

Colin

Yes thanks indeed. I went through a university link but I didn't know
that it was available otherwise. Very handy.
John Kane
Kingston ON

Quoted message said:

Colin Blackburn said:

SlowRider said:

Dunno why you didn't just go to the original Lancet article to see if
it's legit, but through the magic of the internet, here's a link for
those who are interested:

Thanks. Going directly via the Lancet requires payment. That seems a bit
silly if its available elsewhere for free!

Colin

Yes thanks indeed. I went through a university link but I didn't know
that it was available otherwise. Very handy.
John Kane
Kingston ON

The bummer is that the article isn't available to the general public. I
checked with the local university and they don't have a subscription to
that particular journal nor does their ScienceDirect license include
that journal.

-Buck

Buck said:

Quoted message said:

Colin Blackburn said:

SlowRider wrote:
> Dunno why you didn't just go to the original Lancet article to see if
> it's legit, but through the magic of the internet, here's a link for
> those who are interested:

Thanks. Going directly via the Lancet requires payment. That seems a bit
silly if its available elsewhere for free!

Colin

Yes thanks indeed. I went through a university link but I didn't know
that it was available otherwise. Very handy.
John Kane
Kingston ON

The bummer is that the article isn't available to the general public. I
checked with the local university and they don't have a subscription to
that particular journal nor does their ScienceDirect license include
that journal.

-Buck

That is a real bummer, I went through a university connection but see
the post with the link. I was most impressed that one could get it
without a subscription.

BTW that looks like an interesting article you cited. Thanks
John Kane
Kingston ON

Tony Raven said:

It says:
"Leisure-time physical activity was assessed on the
questionnaire as follows: "How often do you participate
in leisure-time physical activity that lasts at least
20-30 mins and causes breathlessness and sweating?"
The six response categories were as follows: (1) daily
(n=201), (2) 2-3 times a week (n=580), (3) once a week
(n=421), (4) 2-3 times a month (n=250), (5) a few times a
year (n=404), and (6) not at all (n=79)."

And that begs the questions: If the participants were suffering from
dementia, how could they accurately assess their current (as indicated
in the question above) exercise regime? If they are only assessing
current exercise, how did they assess prior-years exercise regime? Are
the researchers depending on the memory of the dementia sufferers, or
are they depending on prior data or are they depending on the reporting
from a spouse?

-Buck

Quoted message said:

That is a real bummer, I went through a university connection but see
the post with the link. I was most impressed that one could get it
without a subscription.

If you are going through a university connection, then the university
has a subscription. Science Direct queries the domain from which you
are accessing their servers. If the domain has a subscription, you are
allowed access.

At my alma mater, we could access Science Direct from off campus using
the campus proxy server. We would hit the proxy server from a browser
with our user name and password and the proxy server would connect to
Science Direct and forward the information.

Quoted message said:

BTW that looks like an interesting article you cited. Thanks

I thought it was a good one to share.

-Buck

Buck said:

Tony Raven said:

It says:
"Leisure-time physical activity was assessed on the
questionnaire as follows: "How often do you participate
in leisure-time physical activity that lasts at least
20-30 mins and causes breathlessness and sweating?"
The six response categories were as follows: (1) daily
(n=201), (2) 2-3 times a week (n=580), (3) once a week
(n=421), (4) 2-3 times a month (n=250), (5) a few times a
year (n=404), and (6) not at all (n=79)."

And that begs the questions: If the participants were suffering from
dementia, how could they accurately assess their current (as indicated
in the question above) exercise regime? If they are only assessing
current exercise, how did they assess prior-years exercise regime? Are
the researchers depending on the memory of the dementia sufferers, or
are they depending on prior data or are they depending on the reporting
from a spouse?

Its a long term study (North Karelia Project) in which a cohort has been
followed over long periods of time for a whole range of factors and
outcomes. The activity assessment was done in 1972, 77, 82 and 87 with
the participants assessed again for outcomes in 1998. Fairly standard
technique IME.

--
Tony

"I did make a mistake once - I thought I'd made a mistake but I hadn't"
Anon

I submit that on or about Tue, 04 Oct 2005 17:27:21 +0100, the person
known to the court as Tony Raven <[email hidden]> made a
statement (<[email hidden]> in Your Honour's bundle) to
the following effect:

Quoted message said:

It says:
"Leisure-time physical activity was assessed on the
questionnaire as follows: “How often do you participate
in leisure-time physical activity that lasts at least
20–30 mins and causes breathlessness and sweating?”
The six response categories were as follows: (1) daily
(n=201), (2) 2–3 times a week (n=580), (3) once a week
(n=421), (4) 2–3 times a month (n=250), (5) a few times a
year (n=404), and (6) not at all (n=79)."

And where was "can't remember?"

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

85% of helmet statistics are made up, 69% of them at CHS, Puget Sound

Just zis Guy said:

I submit that on or about Tue, 04 Oct 2005 17:27:21 +0100, the person
known to the court as Tony Raven <[email hidden]> made a
statement (<[email hidden]> in Your Honour's bundle) to
the following effect:

Quoted message said:

It says:
"Leisure-time physical activity was assessed on the
questionnaire as follows: “How often do you participate
in leisure-time physical activity that lasts at least
20–30 mins and causes breathlessness and sweating?”
The six response categories were as follows: (1) daily
(n=201), (2) 2–3 times a week (n=580), (3) once a week
(n=421), (4) 2–3 times a month (n=250), (5) a few times a
year (n=404), and (6) not at all (n=79)."

And where was "can't remember?"

Remember what?

--
Tony

"I did make a mistake once - I thought I'd made a mistake but I hadn't"
Anon

Tony said:

It says:
"Leisure-time physical activity was assessed on the
questionnaire as follows: "How often do you participate
in leisure-time physical activity that lasts at least
20-30 mins and causes breathlessness and sweating?"

....

So riding to work or the grocery store doesn't count? Huh.

--Karen D.

Veloise said:

Tony said:

It says:
"Leisure-time physical activity was assessed on the
questionnaire as follows: "How often do you participate
in leisure-time physical activity that lasts at least
20-30 mins and causes breathlessness and sweating?"

....

So riding to work or the grocery store doesn't count? Huh.

But other forms of leisure time physical activity might ;-)

--
Tony

"I did make a mistake once - I thought I'd made a mistake but I hadn't"
Anon

Tony Raven said:

Veloise said:

Tony said:

It says:
"Leisure-time physical activity was assessed on the
questionnaire as follows: "How often do you participate
in leisure-time physical activity that lasts at least
20-30 mins and causes breathlessness and sweating?"

....

So riding to work or the grocery store doesn't count? Huh.

But other forms of leisure time physical activity might ;-)

--
Tony

20-30 minutes?