"cfs affects 17 million worldwide" - source?

I'm doing research for a YouTube video on CFS prevalence. Does anyone know the source of this figure?

The last good prevalence data came from Leonard Jason's 1999 prevalance study which showed .42% of the US affected - which based on 1993 census data of the US population being 198 million comes to 800,000.

That number has been extrapolated to "over a million" based on more a more recent US population of around 300 million.

So where did the 17 million come from? Is that another extrapolation based on .42% times the world population of 1993? (The numbers don't add up unless you use a world population of 4 billion, which is way low for 1993.)

Or did someone add up all of the various countries estimates of CFS? Where would someone even find this data?
 

George

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Nobody knows, I've been looking for the fountain head of that number for going on two years now. Everybody quotes it but nobody takes responsibility for it. I will say this though, if you go to a good website that shows epidemic spread numbers for AIDES based on decade, sex, partners, transfusion and behavior factors and apply it to CFS that 17 million number works if you start in 1920 and go to 2002. The next generation turn over goes from 17 million to 184 million between 2002 and 2022.
 

George

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Hey I was just looking at a paper that quotes the 17 million number and they have it referenced this way. . .

Ranjith G: Epidemiology of chronic fatigue syndrome. Occup. Med. (Lond.) 55(1), 13-19 (2005)

see if you can get anything off that.
 

Hope123

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I didn't see this number until quite recently and I have looked at some of the CFS literature in the past. I think it came after XMRV came on the scene and has to do not so much with "CFS" but rather with estimates of prevalence of XMRV, which includes both symptomatic CFS, infected carriers, people with prostate cancer (not all, as we know so far), etc. Did it come from Dr. Mikovits or WPI?

I haven't looked at George's reference. No full-text available for me but abstract is from Psychological Department of King's College, London, and they state CFS is "relatively rare" - paper might focus on "chronic fatigue."

My feeling is that this figure might be overblown or is not particularly accurate based on the data we have to date so I would use it with caution. Dr. Jason's studies on CFS are confined primarily to the US but I trust his numbers for the US. If they extrapolated his data to the world, that might not be accurate. Only time will tell.
 
That study wasn't helpful, but I think I had a breakthrough:

Afari / Buchwald 2003
http://ajp.psychiatryonline.org/cgi/content/full/160/2/221#SEC2

CFS prevalence varies from 0.007% to 2.8%

world population 2003 = 6,317,426,395

.0028 x 6,317,426,395 = 17,688,793 aha!

So this would be taking the high number from Afari/Buchwald's study (which is a lot less than Jason's number, and so would be conservative), and multiplying it by the world population at the time of the study.
 

George

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That study wasn't helpful, but I think I had a breakthrough:

Afari / Buchwald 2003
http://ajp.psychiatryonline.org/cgi/content/full/160/2/221#SEC2

CFS prevalence varies from 0.007% to 2.8%

world population 2003 = 6,317,426,395

.0028 x 6,317,426,395 = 17,688,793 aha!

So this would be taking the high number from Afari/Buchwald's study (which is a lot less than Jason's number, and so would be conservative), and multiplying it by the world population at the time of the study.
:victory::victory:
Great Catch Caledonia! I think you have found the fountain head for the original number.​
:victory::victory:

Hope123, this number has been around about two years before XMRV came on the scene. If XMRV prevalence rates hold up to the 3.5% world wide which is a reasonable estimate that would be around 200 million infected. So the numbers surrounding XMRV are not anywhere in the same ballpark of CFS. That's why there is speculation that XMRV may be a vector for many other illnesses.

If you start adding "known" numbers world wide for ME/CFS you (with a little speculation on the blanks) do come up with around 17 million for CFS for instance 850,000 in the US, 250,000 in the UK, 350,000 in Germany and so on and so forth. I tried to add them all up one time and my head just about exploded. (grins)
 

Hope123

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That study wasn't helpful, but I think I had a breakthrough:

Afari / Buchwald 2003
http://ajp.psychiatryonline.org/cgi/content/full/160/2/221#SEC2

CFS prevalence varies from 0.007% to 2.8%

world population 2003 = 6,317,426,395

.0028 x 6,317,426,395 = 17,688,793 aha!

So this would be taking the high number from Afari/Buchwald's study (which is a lot less than Jason's number, and so would be conservative), and multiplying it by the world population at the time of the study.
Hmm........doesn't 2.8% = 0.028 rather than 0.0028=0.28%? When I multiplied it with the population figure you have, I get 176 million. This is the higher number from Afari.

I agree though that if you're using 0.0028=0.28%, this is less than Jason's figure of 0.4%.

I am concern about extrapolations though as although some people can take this figure with a grain of salt and the precautions needed, others will use it without caution and, if it doesn't hold up, we end up with egg on our face. I've seen people misinterpret Jason's study on mortality in CFS and another experienced CFS researcher has seen this happen with statements about heart issues in CFS.
 

Dolphin

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If one uses the 0.4 figure from Jason (0.422 to be more accurate http://archinte.ama-assn.org/cgi/content/full/159/18/2129 ), one might be able to get it as it applied to adults. The prevalence for children is a lot smaller.

But extrapolations certainly have risks.
Although the study in Nigeria http://www.ncbi.nlm.nih.gov/pubmed/17439996 suggested a prevalence of 0.7% there using similar methods to the Chicago study so the figure may not necessarily be smaller than 17 million.
Also some of those excluded for having other medical or psychiatric conditions in the prevalence studies such as Jason et al., 1999 may also have CFS really i.e. if there was a simple test where one didn't have to exclude people because they have "fatigue" or whatever.
 

Dolphin

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Hey I was just looking at a paper that quotes the 17 million number and they have it referenced this way. . .

Ranjith G: Epidemiology of chronic fatigue syndrome. Occup. Med. (Lond.) 55(1), 13-19 (2005)

see if you can get anything off that.
Here is an extract from that paper (a lot of it is on fatigue, etc):

Prevalence of CFS

Primary care studies

The study by David et al. [16] discussed earlier found
only one case of a CFS-like illness in a sample of 611
primary care attendees. A later study by the same group
[19] used a 2-stage procedure. They screened 686
patients attending primary care physicians and identified
77 individuals with chronic fatigue. Of these, 65 underwent
a comprehensive medical and psychological evaluation.
Twenty-six percent met the British criteria for
CFS. Many of these studies had small sample sizes and
inappropriate sampling procedures.

In one of a series of London-based studies, Wessely
et al. [20] conducted a prospective study to determine the
prevalence of CFS in 1199 primary care attendees with
symptoms of common infection and 2267 seen for other
reasons. They managed a follow-up rate of 84% at 6
months. At 6 months, 9.9% of the infectious group and
11.7% of the control group reported chronic fatigue and
there was no difference in the proportions of the case
groups fulfilling criteria for CFS. The study also looked at
the prevalence of various definitions of CFS. The overall
prevalence of CDC-1994, Oxford, Australian and CDC-
1988 criteria were 2.6, 2.2, 1.4 and 1.2%, respectively;
these values fell further when co-morbid psychiatric
disorders were excluded. This compares with an American
primary care study which found rates of 0.3, 0.4 and
1% for CDC-1988, British and Australian definitions,
respectively [21].

Community-based studies

Price et al. [22] used the Diagnostic Interview Schedule
(DIS) to assess the presence of CFS according to the
CDC-1988 definition. While 23% of the participants
reported experiencing persistent fatigue sometime during
their lives, only 1 of 13 538 peoplemet a diagnosis of CFS
fulfilling all exclusion and inclusion criteria. This gave a
prevalence figure of 7/100 000. The study of Price et al.
[22], though, has numerous methodological problems.
The definition of CFS did not correspond to other
definitions. The other problem was that symptoms were
assessed on a lifetime basis, leading to the possibility that
cases where medical or psychiatric conditions existed at a
different time may have been excluded. The lack of
medical work-up or laboratory analyses was also a failing.
The CDC conducted a community-based survey in
San Fransisco [23]. Using telephone interviews, 14 627
adults were studied of whom 4.3% reported chronic
fatigue. Having excluded cases with medical or psychiatric
diagnoses that could potentially explain fatigue, the
investigators identified 1.8% of the population as having
idiopathic chronic fatigue and 0.2% as having a CFS-like
illness.

Jason et al. [24] studied the point prevalence of CFS in
an ethically diverse random community sample. The
study was a methodologically sophisticated one with a
2-stage procedure. In the first stage, the patients were
screened using a questionnaire and those who screened
positive for a CFS-like illness were interviewed on the
Structured Clinical Interview for the Diagnostic and
Statistical Manual (SCID) in the second stage. This was
followed by a detailed medical examination and investigations.
The final diagnosis of CFS was made by two
independent raters. The study found a prevalence of
0.42% in the sample.

The wide disparity in the figures for prevalence of CFS
in various studies (see Table 2) is likely to be due to
differences in methodology rather than a true difference
in prevalance. It seems clear that random communitybased
samples, an extensive search for a medical
abnormality and restrictive case definitions result in
lower prevalence figures. It is noteworthy that a recent
Australian study found a prevalence rate of 1.5% in the
population for neurasthenia, a related disorder [25].
The Nigerian study (Njoku, Jason & Torres-Harding) came out after (2007).
 

muffin

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Next question on figures we use: "1 out of 14 people are carriers for XMRV"???

Does anyone know where the figure "1 out of 14 people are carriers for XMRV"????

I have used that number but forgot where I found it. Ideas?
 

muffin

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Thanks V99. I am guilty of using figures that I forget where I read them from. Then I wonder if I really made them up in my sad little head!!!
 
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There is too much happening right now, and all we want is the Alter paper. It befuddles the brain. I posted the numbers, but didn't really know if they were correct. (giggles)
My excuse at the mo is the strong pain killers I am now trying for my duff wrist. It is so much fun. So very floaty light. Hopefully it will wear off soon. (giggles)
 
Oh Hope, you're right. I was wondering if my math skills were a little suspect. I'm glad I put this out there.

So we're looking for a number that would be around .2% or .3%. And then I'm not sure what year of world population to base it on.

I also found this extrapolation on wrongdiagnosis.com.
http://www.wrongdiagnosis.com/c/chronic_fatigue_syndrome/stats-country.htm

That one uses the very conservative CDC figure of .18% which is close to .2%.
(.18%) x 6 393 120 940 = 11 507 617 (world population 2004)
 

George

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Thanks Dolphin for pulling out the relevant info on that paper.

I guess the short answer is nobody has been keeping track and it's all guess work. Looks like the formula works something like this. . .

You take a country's population and the currently known number of CFS patients and divided to get a prevalence rate.
Do that with 10 countries, let's say
Take those 10 number and get an average
Then multiply that average by the current world population

Anybody got stats on say 10 countries we could figure out our own CFS numbers.