@Hip was asking you to do your own work here. Granted, little has been found regarding the etiology and treatment of ME/CFS, but there's certainly plenty on the epidemiology of the illness. Even if you take into account the controversies regarding diagnostic criteria, you can't say there isn't plenty of research in this area. FYI, this is list of about 40 publications on the "prevalence of CFS" from "ME-Web" (which took me about 5 minutes to find on a web search).
- Bates D.W., Schmitt W., Lee J., Kornish R.J., Komaroff A.L. (1991) Prevalence of fatigue and chronic fatigue syndrome in a primary care practice. Clinical Research., 39, A571-A571.
- Bates, D.W., Schmitt, W., Buchwald, D., et al. (1993). Prevalence of fatigue and chronic fatigue syndrome in a primary care practice. Archives of Internal Medicine.,153, 2759-2765.
- Bazelmans, E., Vercoulen, J.H., Galama, J.M., van Weel, C., van der Meer, J.W. & Bleijenberg, G. (1997). Prevalence of chronic fatigue syndrome and primary fibromyalgia syndrom in The Netherlands. Ned. Tijdschr. Geneeskd., 141, 1520-1523.
- Buchwald, D., Umali, P., Umali, J., Kith, P., Pearlman, T. & Komaroff, A. L. (1995). Chronic fatigue and the chronic fatigue syndrome: prevalence in a Pacific Northwest health care system. Ann. Intern. Med., 123 (2), 81-88.
- Calder, B. D., Warnock, P. J., McCartney, R. A. & Bell, E. J. (1987). Coxsackie B viruses and the post-viral syndrome: a prospective study in general practice. J. R. Coll. Gen. Pract., 37 (294), 11-14.
- David, A., Pelosi, A. & McDonald, E. (1990). Tired, weak or in need of rest: fatigue among general practice attenders. British Medical Journal, 301, 1199-1222.
- Gunn, W. J., Connell, D.B. & Randall, B. (1993). Epidemiology of chronic fatigue syndrome: the Centers for Disease Control Study. Ciba Foundation Symposium, 173, 83-93.
- Hickie, I.B., Hooker, A.W., Hadzi-Pavlovic, D., Bennett, B.K., Wilson, A.J. & Lloyd, A.R. (1996). Fatigue in selected primary care settings; sociodemographic and psychiatric correlates. Med. J. Aust., 164, 585-588.
- Ho-Yen, D.O. (1988). The epidemiology of postviral fatigue syndrome. Scot. Med. J., 33, 368-369.
- Ho-Yen, D.O. & McNamara, I. (1991). General practitioners´ experience of the chronic fatigue syndrome. Br. J. Gen. Pract., 41, 324-326.
- Jason, L.A., Taylor, R., Wagner, L., et al. (1995). Estimating rates of chronic fatigue syndrome from a community-based sample: a pilot study. Am. J. Community Psychol., 23, 557-568.
- Jason, L. A., Wagner, L., Rosenthal, S., Goodlatte, J., Lipkin, D., Papernik, M., Plioplys, S. & Plioplys, A. V. (1998). Estimating the prevalence of chronic fatigue syndrome among nurses. American Journal of Medicine, 105 (3A), 91-93.
- Jason, L. A., Richman, J. A., Rademaker, A. W., Jordan, K. M., Plioplys, A. V., Taylor, R. R., McCready, W., Huang, C. F. & Plioplys, S. (1999). A community-based study of chronic fatigue syndrome. Arch. Intern. Med., 159 (18), 2129-2137.
- Kawai, K. & Kawai, A. (1992). Studies on the relationship between chronic fatigue syndrome and Epstein-Barr virus in Japan. Intern. Med., 31 (3), 313-318.
- Kawakami, N., Iwata, N., Fujihara, S. & Kitamura, T. (1998). Prevalence of chronic fatigue syndrome in a community population in Japan. Tohoku J. Exp. Med., 186, 33-41.
- Kenter, E.G. & Okkes, I.M. (1999). Patients with fatigue in family practice: prevalence and treatment. Ned. Tijdschr. Geneeskd., 143, 796-801.
- Klein Rouweler, E. Severens J.L., Bleijenberg, G (1999). Prevalentie-rapport. University Hospital Nijmegen, The Netherlands
- Lawrie, S.M. & Pelosi, A. J. (1995). Chronic fatigue syndrome in the community. Prevalence and associations. British Journal of Psychiatry, 166, 793-797.
- Lawrie, S.M., Manders, D.N., Geddes, J.R. & Pelosi, A. (1997). A population-based incidence study of chronic fatigue. Psychol. Med., 27, 343-353.
- Lloyd, A.R., Hickie, I., Boughton, C.R., Spencer, O. & Wakefield, D. (1990). Prevalence of chronic fatigue syndrome in an Australian population. Med. J. Aust., 153, 522-528.
- Lloyd, A.R., Pender, H. (1992). The economic impact of chronic fatigue syndrome. Med. J. Aust., 157, 599-601.
- McDonald, E., David, A. S., Pelosi, A. J. & Mann, A. H. (1993). Chronic fatigue in primary care attenders. Psychol. Med., 23 (4), 987-998.
- Minowa, M. & Jiamo, M. (1996). Descriptive epidemiology of the chronic fatigue syndrome based on a nationwide survey in Japan. J. Epidemiol., 6, 75-80.
- Murdoch, J.C. (1988). The myalgic encephalomyelitis syndrome. Fam. Pract., 5, 302-306.
- Nisenbaum, R., Jones, A., Jones, J. & Reeves, W. (2000). Longitudinal analysis of symptoms reported by patients with chronic fatigue syndrome. Ann. Epidemiol., 10 (7), 458.
- Price, R.K., North, C.S., Wessely, S. & Fraser, V.J. (1992). Estimating the prevalence of chronic fatigue syndrome and associated symptoms in the community. Public Health Rep., 107, 514-522.
- Reeves, W.C. (1999) Prevalence of chronic fatigue syndrome. Update Reyes et al., 1998 Transcript CFSCC Meeting, April 21-22, 1999.
- Reyes M., Nisenbaum. R., Hoaglin D., Reeves W.C. (1998) Prevalence of chronic fatigue syndrome. CDC Executive Summary, October 10, 1998.
- Shefer, A., Dobbins, J.G., Fukuda, K., Steele, L., Koo, D., Nisenbaum, R. & Rutherford, G.W. (1997). Fatiguing illness among employees in three large state office buildings, California, 1993: was there an outbreak? J. Psychiatr. Res., 31, 45-50.
- Steele, L., Dobbins, J.G., Fukuda, K., Reyes, M., Randall, B., Koppelman, M. & Reeves, W.C. (1998). The epidemiology of chronic fatigue in San Francisco. American Journal of Medicine, 105, 83-90.
- Versluis, R.G., de Waal, M.W., Opmeer, C., Petri, H. & Springer, M.P. (1997). Prevalence of chronic fatigue syndrome in 4 family practices in Leiden. Ned. Tijdschr. Geneeskd., 141, 1523-1526.
- Wagner, L.I. and Jason L.A. (1997). Outcomes of occupational stressors on nurses: Chronic fatigue syndrome-related symptoms. Nursing connections, 10, 41-49.
- Wessely, S., Chalder, T., Hirsch, S., Wallace, P., & Wright, D. (1997). The prevalence and morbidity of chronic fatigue and chronic fatigue syndrome: a prospective primary care study. Am. J. Public Health, 87(9), 1449-1455.
No, you cannot bend any of my fingers beyond 90º, at least not without me punching you for breaking my fingers! I score 6/9 on the Beighton scale sometimes, and sometimes 5, and I'm 57 years old, but I cannot bending either pinky finger back past 90º. Maybe I could have as a child, but no way now. Maybe that's because I have a lot of joint stiffness in my hands since becoming ill.
It's also important to note that there are specifics to the way the Beighton scale should be applied. It's not as simple as just bending a certain joint so far. Here are the precise details (from
here).
"PLEASE NOTE: When reading about this in professional textbooks the formal language used is as follows:
(A) With the palm of the hand and forearm resting on a flat surface with the elbow flexed at 90°, if the metacarpal-phalangeal joint of the fifth finger can be hyperextended more than 90° with respect to the dorsum of the hand, it is considered positive, scoring 1 point.
(B) With arms outstretched forward but hand pronated, if the thumb can be passively moved to touch the ipsilateral forearm it is considered positive scoring 1 point.
(C) With the arms outstretched to the side and hand supine, if the elbow extends more than 10°, it is considered positive scoring 1 point.
(D) While standing, with knees locked in genu recurvatum, if the knee extends more than 10°, it is considered positive scoring 1 point.
(E) With knees locked straight and feet together, if the patient can bend forward to place the total palm of both hands flat on the floor just in front of the feet, it is considered positive scoring 1 point."
Furthermore, there's more to a diagnosis of Ehlers Danlos Syndrome than a diagnosis of hypermobile joints. Each of the 13 subtypes has specific diagnostic criteria as established by The International EDS Consortium in 2017. Here is a link to the criteria for all of the subtypes (of which hypermobile EDS or hEDS is the most common):
EDS Diagnostics 2017. Here's a link to a handy PDF form for diagnosing hEDS: "
Diagnostic Criteria for Hypermobile Ehlers-Danlos Syndrome (hEDS)".
Here's a nice summary of the diagnostic criteria for hEDS (from
here).
"The clinical diagnosis of hEDS needs the simultaneous presence of criteria 1 and 2 and 3. This is a complex set of criteria, and there is much more detail than presented in this overview; please see the page for hypermobile EDS [see link above].
1. Generalized joint hypermobility (GJH); and
2. Two or more of the following features must be present (A & B, A & C, B & C, or A & B & C):
Feature A—systemic manifestations of a more generalized connective tissue disorder (a total of five out of twelve must be present)
Feature B—positive family history, with one or more first degree relatives independently meeting the current diagnostic criteria for hEDS
Feature C—musculoskeletal complications (must have at least one of three); and
3. All these prerequisites must be met: absence of unusual skin fragility, exclusion of other heritable and acquired connective tissue disorders including autoimmune rheumatologic conditions, and exclusion of alternative diagnoses that may also include joint hypermobility by means of hypotonia and/or connective tissue laxity."
And very important to this discussion is the following caveat to consider when diagnosing hEDS [Italics mine]:
"There is a range of conditions which can accompany hEDS, although there is not enough data for them to become diagnostic criteria. While they’re associated with hEDS, they’re not proven to be the result of hEDS and they’re not specific enough to be criteria for diagnosis. Some of these include
sleep disturbance, fatigue, postural orthostatic tachycardia, functional gastrointestinal disorders, dysautonomia, anxiety, and depression. These conditions may be more debilitating the joint symptoms; they often impair daily life, and they should be considered and treated." (from
here)
So, people with hEDS may have many symptoms that overlap with those of ME/CFS, but those symptoms are neither necessary or sufficient for a hEDS diagnosis, while they are essential to an ME/CFS diagnosis (depending on which criteria is used this could include e.g. fatigue, sleep disturbance, orthostatic intolerance, GI disorders, and cognitive problems). Here's an excellent resource for the 5 diagnostic criteria for ME/CFS used in research:
Open Medicine Foundation: Diagnosis of ME/CFS.