- Jul 2018
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europepmc.org europepmc.org
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On 2014 Apr 16, Tom Kindlon commented:
Prevalence estimates have been inflated due to the female predominance in the samples
(I previously posted this as a comment on the Br J Psych http://bjp.rcpsych.org/content/194/2/117.abstract/reply#content-block but not everyone may see it there)
We are not given information on the gender breakdown of Chronic Fatigue Syndrome (CFS) in this study but if it is in-line with other studies in the field, females would be much more likely to have CFS. Given a much larger percentage of the cohorts are female compared to the general population, this would mean that the (adjusted) prevalence rates for each country would be lower.
The total number of CFS cases found in a particular country cohort = Number of women with CFS + Number of men with CFS = P(CFS|F)N(F)+P(CFS|M)N(M) where F=Female, M=Male, N(F)=Number of Females, P(CFS|F)=Probability of a female having CFS, etc.
If one takes P(CFS|M)=0.25*P(CFS|F), which would be comparable to an approximate average of previous studies (for example, [1-4]), and assumes the number of men and women are equal in the 18-45 age bracket, the prevalence rates for CFS in the UK and Brazil are 1.65% and 1.21% respectively.
These figures in themselves are an upper bound on the true prevalence rates, given individuals in neither group went through rigorous and thorough individual assessments to exclude other conditions.
References:
[1] Bazelmans E, Vercoulen JH, Swanink CM, Fennis JF, Galama JM, van Weel C, van der Meer JW, Bleijenberg G. Chronic Fatigue Syndrome and Primary Fibromyalgia Syndrome as recognized by GPs. Fam Pract. 1999 Dec;16(6):602-4.
[2] Jason LA, Richman JA, Rademaker AW, Jordan KM, Plioplys AV, Taylor RR, McCready W, Huang CF, Plioplys S. A community-based study of chronic fatigue syndrome. Arch Intern Med. 1999 Oct 11;159(18):2129-37.
[3] Kim CH, Shin HC, Won CW. Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study. J Korean Med Sci. 2005 Aug;20(4):529-34.
[4] Reyes M, Nisenbaum R, Hoaglin DC, Unger ER, Emmons C, Randall B, Stewart JA, Abbey S, Jones JF, Gantz N, Minden S, Reeves WC. Prevalence and incidence of chronic fatigue syndrome in Wichita, Kansas. Arch Intern Med. 2003 Jul 14;163(13):1530-6.
This comment, imported by Hypothesis from PubMed Commons, is licensed under CC BY.
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- Feb 2018
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europepmc.org europepmc.org
-
On 2014 Apr 16, Tom Kindlon commented:
Prevalence estimates have been inflated due to the female predominance in the samples
(I previously posted this as a comment on the Br J Psych http://bjp.rcpsych.org/content/194/2/117.abstract/reply#content-block but not everyone may see it there)
We are not given information on the gender breakdown of Chronic Fatigue Syndrome (CFS) in this study but if it is in-line with other studies in the field, females would be much more likely to have CFS. Given a much larger percentage of the cohorts are female compared to the general population, this would mean that the (adjusted) prevalence rates for each country would be lower.
The total number of CFS cases found in a particular country cohort = Number of women with CFS + Number of men with CFS = P(CFS|F)N(F)+P(CFS|M)N(M) where F=Female, M=Male, N(F)=Number of Females, P(CFS|F)=Probability of a female having CFS, etc.
If one takes P(CFS|M)=0.25*P(CFS|F), which would be comparable to an approximate average of previous studies (for example, [1-4]), and assumes the number of men and women are equal in the 18-45 age bracket, the prevalence rates for CFS in the UK and Brazil are 1.65% and 1.21% respectively.
These figures in themselves are an upper bound on the true prevalence rates, given individuals in neither group went through rigorous and thorough individual assessments to exclude other conditions.
References:
[1] Bazelmans E, Vercoulen JH, Swanink CM, Fennis JF, Galama JM, van Weel C, van der Meer JW, Bleijenberg G. Chronic Fatigue Syndrome and Primary Fibromyalgia Syndrome as recognized by GPs. Fam Pract. 1999 Dec;16(6):602-4.
[2] Jason LA, Richman JA, Rademaker AW, Jordan KM, Plioplys AV, Taylor RR, McCready W, Huang CF, Plioplys S. A community-based study of chronic fatigue syndrome. Arch Intern Med. 1999 Oct 11;159(18):2129-37.
[3] Kim CH, Shin HC, Won CW. Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study. J Korean Med Sci. 2005 Aug;20(4):529-34.
[4] Reyes M, Nisenbaum R, Hoaglin DC, Unger ER, Emmons C, Randall B, Stewart JA, Abbey S, Jones JF, Gantz N, Minden S, Reeves WC. Prevalence and incidence of chronic fatigue syndrome in Wichita, Kansas. Arch Intern Med. 2003 Jul 14;163(13):1530-6.
This comment, imported by Hypothesis from PubMed Commons, is licensed under CC BY.
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