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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)

Group

Community

Primary care

Total

Number of articles included (%)

30 (67)

15 (33)

45 (100)

Number of studies includeda(%)

30 (65)

16 (35)

46 (100)

Prospective

25 (54)

16 (35)

41 (89)

Retrospective

4 (9)

1 (2)

5 (11)

Number of prevalence datab (%)

33 (59)

23 (41)

56 (100)

Total number of participants

540,901

545,075

1085,976

Mean N. of participants

18,030 ± 38,094

34,067 ± 61,325

23,608 ± 48,092

Total number of known sexc

120,765

10,077

130,842

 Male

58,752

3318

62,070

 Female

62,013

6759

68,772

 M:F ratio

48:52

25:75

45:55

Mean age of participantsd

41.1 ± 11.3

38.0 ± 6.5

40.0 ± 9.9

 Male

41.1 ± 11.3

38.0 ± 6.8

39.9 ± 10.0

 Female

41.2 ± 11.4

38.1 ± 6.1

40.0 ± 9.8

N. of (studies)/prevalence data by subgroup (N. of participants)

 Publication year

  1990–2000

8

(177,201)

15

(318,391)

(18)/23

(495,592)

  2001–2010

19

(86,512)

4

(9895)

(20)/23

(96,407)

  2011–2018

6

(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 populatione

3

(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/Ag

1

(59,101)

1

(1874)

2

(60,975)

 Country (13 countries)

  

  Western

27

(516,617)

17

(473,009)

(34)/44

(989,626)

  Asian

5

(23,197)

5

(70,192)

(10)/10

(93,389)

  Othersh

1

(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 diagnosis

1

(114,000)

5

(435,782)

(4)/6

(549,782)

  Medical records

4

(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