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Table 1 Characteristics of studies on the prevalence of CFS/ME (± SD)

From: Systematic review and meta-analysis of the prevalence of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)

GroupCommunityPrimary careTotal
Number of articles included (%)30 (67)15 (33)45 (100)
Number of studies includeda(%)30 (65)16 (35)46 (100)
Prospective25 (54)16 (35)41 (89)
Retrospective4 (9)1 (2)5 (11)
Number of prevalence datab (%)33 (59)23 (41)56 (100)
Total number of participants540,901545,0751085,976
Mean N. of participants18,030 ± 38,09434,067 ± 61,32523,608 ± 48,092
Total number of known sexc120,76510,077130,842
 Male58,752331862,070
 Female62,013675968,772
 M:F ratio48:5225:7545:55
Mean age of participantsd41.1 ± 11.338.0 ± 6.540.0 ± 9.9
 Male41.1 ± 11.338.0 ± 6.839.9 ± 10.0
 Female41.2 ± 11.438.1 ± 6.140.0 ± 9.8
N. of (studies)/prevalence data by subgroup (N. of participants)
 Publication year
  1990–20008(177,201)15(318,391)(18)/23(495,592)
  2001–201019(86,512)4(9895)(20)/23(96,407)
  2011–20186(277,188)4(216,789)(8)/10(493,977)
 Population group
  General population (≥ 18 years)24(489,961)20(466,565)(34)/44(956,526)
  Children/adolescents (< 18 years)6(43,671)1(73,636)(7)/7(117,307)
  Specific populatione3(7269)2(4874)(5)/5(12,143)
 Case definition (8 case definitions)23(339,192)11(298,739)34(637,931)
  CDC-1994 [22]4(20,037)4(27,454)8(47,491)
  Holmes [23]2(116,520)2(2980)4(119,500)
  Australian [25]2(3215)2(2980)4(6195)
  Oxford [24]1(10,396)3(505,299)4(515,695)
  CCC [27] ECD [26] PVES [28] NICE [29] f N/Ag1(59,101)1(1874)2(60,975)
 Country (13 countries)  
  Western27(516,617)17(473,009)(34)/44(989,626)
  Asian5(23,197)5(70,192)(10)/10(93,389)
  Othersh1(1087)1(1874)(2)/2(2961)
 Diagnostic method  
  Interview (medical test −)19(111,943)3(68,848)(19)/22(180,791)
  Interview (medical test +)9(57,339)14(17,445)(18)/23(74,784)
  Physician diagnosis1(114,000)5(435,782)(4)/6(549,782)
  Medical records4(257,619)1(23,000)(5)/5(280,619)
  1. aThe number of studies is larger (n = 46) than the number of article as one article included two studies
  2. bSome articles included multiple applications of case definitions; thus, the number is larger than the total number of studies
  3. cTwenty-one studies (24 prevalence data points) included information about participant sex
  4. dThe mean age of the participants whose sex was known (12 studies) was estimated using either the reported mean age for each sex or the mean age for both. Children and adolescents were excluded
  5. eSpecific groups included nurses, Gulf War veterans, livestock workers, company employees, etc
  6. fCCC, Canadian Consensus Criteria; ECD, epidemiological case definition; PVES, post viral exhaustion syndrome; and NICE, National Institute for Health and Care Excellence guideline 2007
  7. gTwo N/A cases had no verification of case definition or defined criteria
  8. hOther countries included India and Nigeria