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Joint Bone Spine 76 (2009) 184e187

Original article

Fibromyalgia syndrome in the general population of France:A prevalence study

Bernard Bannwarth a,*, Francis Blotman b, Katell Roue-Le Lay c, Jean-Paul Caubere c,Etienne Andre d, Charles Ta€ıeb c

a Rheumatology Department, University Hospital Pellegrin, Bordeaux, Franceb Rheumatology Department, University Hospital Lapeyronie, Montpellier, France

c Laboratoires Pierre Fabre, Boulogne-Billancourt, Franced Medecin de Sante Publique, Grenoble, France

Accepted 3 June 2008

Available online 25 September 2008

Abstract

Objective: To estimate the prevalence of fibromyalgia (FM) syndrome in the French general population.Methods: A validated French version of the London Fibromyalgia Epidemiology Study Screening Questionnaire (LFESSQ) was administered viatelephone to a representative community sample of 1014 subjects aged over 15 years, selected by the quota method. A positive screen wasdefined as: (1) meeting the 4-pain criteria alone (LFESSQ-4), or (2) meeting both the 4-pain and 2-fatigue criteria (LFESSQ-6). To estimate thepositive predictive value of LFESSQ-4 and LFESSQ-6, this questionnaire was submitted to a sample of rheumatology outpatients (n¼ 178), whowere then examined by a trained rheumatologist to confirm or exclude the diagnosis of FM according to the 1990 American College ofRheumatology criteria. The prevalence of FM in the general population was estimated by applying the predictive positive value to eligiblecommunity subjects (i.e., positive screens).Results: In the community sample, 9.8% and 5.0% screened positive for LFESSQ-4 and LFESSQ-6, respectively. Among rheumatologyoutpatients, 47.1% screened positive for LFESSQ-4 and 34.8% for LFESSQ-6 whereas 10.6% were confirmed FM cases. Based on positivescreens for LFESSQ-4, the prevalence of FM was estimated at 2.2% (95% CI 1.3e3.1) in the French general population. The correspondingfigure was 1.4 % (95% CI 0.7e2.1) if positive screens for LFESSQ-6 were considered.Conclusion: Our findings suggest that FM is also a major cause of widespread pain in France since a point prevalence of 1.4% would translate inapproximately 680,000 patients.� 2008 Elsevier Masson SAS. All rights reserved.

Keywords: Fibromyalgia; Prevalence; Screening Questionnaire; Chronic widespread pain; Fatigue

1. Introduction

Fibromyalgia (FM) syndrome is currently defined by clinicalcriteria established by the American College of Rheumatology(ACR) as widespread pain for at least 3 months and the pres-ence of at least 11 of 18 specified tender points on examination[1]. Though the combination of these two criteria provided

* Corresponding author. Service de Rhumatologie, Groupe hospitalier Pel-

legrin, Place Amelie Raba-Leon, 33076 Bordeaux, France. Tel.: þ33 556 795

556; fax: þ33 557 571 796.

E-mail address: bernard.bannwarth@u-bordeaux2.fr (B. Bannwarth).

1297-319X/$ - see front matter � 2008 Elsevier Masson SAS. All rights reserved

doi:10.1016/j.jbspin.2008.06.002

a sensitivity of 88.4% and specificity of 88.1% in distinguishingFM from other causes of chronic musculoskeletal pain, addi-tional complaints, especially fatigue, sleep disturbance and/orunrefreshing sleep, morning stiffness, paresthesia and psycho-logical distress are frequent in FM [1]. In this respect, fatigueconstitutes one of the most troublesome and common problemin these patients [2].

FM is recognized as a common condition in the clinic anda major cause of morbidity world wide. Based on clinicalstudies undertaken in various countries, the prevalence of FMwas found to be between 0.5% and 5% in the general pop-ulation [3]. This wide range of prevalence estimates may be

.

185B. Bannwarth et al. / Joint Bone Spine 76 (2009) 184e187

ascribed to methodological differences across studies as wellas actual differences in FM prevalence between countries[4,5]. To our knowledge, no studies assessed the prevalence ofFM in the French population.

The main objective of the present study was to assess theprevalence of FM in France. It aimed also at describing thesociodemographic characteristics of patients with FM.

2. Methods

2.1. Screening survey in the general population

The screening survey used the London FibromyalgiaEpidemiology Study Screening Questionnaire (LFESSQ)developed by the Department of Epidemiology and Biosta-tistics, Rheumatology Division of the University of London inWestern Ontario [5]. This questionnaire was designed with 4items relating to chronic pain and 2 items relating to fatigue(Table 1). The original LFESSQ was translated into Frenchwith the permission of its authors, and validated according toa standardized method including forward translation, qualitycontrol, back-translation, and pre-evaluation [6]. The Frenchversion was administered to 20 consenting patients with FM inorder to test its understanding, clarity, and cultural andlinguistic equivalence with the original version. The patientswere invited to respond to the questionnaire on 2 occasions 10days apart. This time frame was choosen since the disease wasunlikely to change during this period and patients wereunlikely to remember answers given at the first administrationof the questionnaire. The scores between the two successiveadministrations (testeretest reliability) correlated well.

Interviews were carried out via telephone in September2006 by Ipsos professional interviewers and conductedaccording to standardized modalities. The Computer AssistedTelephone Interview (CATI) system was used to obtaina probabilistic sample representative of the general populationof more than 15 years. Subjects were selected using the quotamethod (sex, age, and occupation of the head of family) withstratification according to the geographical area/city. Eligible

Table 1

The London Fibromyalgia Epidemiology Study Screening Questionnaire [5]

Pain criteria

In the past three months

1. Have you had pain in muscles, bones or joints, lasting at least one week?

2. Have you had pain in your shoulders, arms or hands? On which side?

Right, left or both?

3. Have you had pain in your legs or feet? On which side? Right, left or

both?

4. Have you had pain in your neck, chest or back?

Meeting the pain criteria requires ‘‘yes’’ responses to all four pain items, and

either (1) both a right and left side positive response, or (2) a both sidespositive response.

Fatigue criteria

5. Over the past three months, do you often felt tired or fatigued?

6. Does tiredness or fatigue significantly limit your activities?

Screening positive for chronic, debilitating fatigue requires a ‘‘yes’’ response

to both fatigue items

contacts were administered the French LFESSQ and werealso asked questions on sociodemographic characteristics,including sex, age, marital status, level of education, occupa-tion, and domicile (geographical area and size of the city).According to White et al. [5], a positive screen was defined inone of 2 ways: (1) meeting the pain criteria alone (LFESSQ-4),or (2) meeting both the pain and fatigue criteria (LFESSQ-6).

2.2. Rheumatology outpatients

The French version of the LFESSQ was administeredduring a 30-day period to 178 consecutive, consenting andmentally competent patients who were consulting two rheu-matologists practising in the Rheumatology departments ofPellegrin and Lapeyronie university hospitals, regardless ofthe reason for the visit. The above-mentioned sociodemo-graphic characteristics were also recorded. Immediately afterthe screening interview, patients were examined to confirm orexclude FM. To be classified as an FM case, patients whoscreened positive for either LFESSQ-4 or LFESSQ-6 had tomeet the full ACR criteria [1], i.e., (1) at least 3 months’duration of widespread pain, the distribution of whichincluding both the right and left side of the body, both aboveand below the waist, and both the axial and peripheral skel-eton, and (2) pain in at least 11 of 18 tender point sites ondigital palpation. In accordance with the ACR criteria, primaryand secondary-concomitant FM were not distinguished [1].The positive predictive value (PPV) of LFESSQ-4 andLFESSQ-6 was calculated as the number of confirmed FMcases divided by the number of rheumatology outpatients whoscreened positive for either LFESSQ-4 or LFESSQ-6,respectively [7].

2.3. Estimates of point prevalence of FM in the generalpopulation

The estimates of the prevalence of FM in the generalpopulation were based upon the assumption that the PPV ofLFESSQ-4 and LFESSQ-6 in this population would be similarto those calculated in the rheumatology outpatients sample. Assuch, the point prevalence of FM was the percentage ofcommunity subjects who screened positive for LFESSQ-4 orLFESSQ-6 multiplied by the corresponding PPV.

2.4. Statistical analysis

Statistical analysis using the SAS Software version 8.2 wastwo-sided and performed at the 5% significance level. The c

2

test was used for qualitative data and analysis of variance(ANOVA) for quantitative data.

3. Results

In the representative community sample (n¼ 1014),subjects were aged 15e91 years (mean� SD: 44.9� 18.2)and 52.1% were females. In total, 9.8% and 5.0% screenedpositive for LFESSQ-4 and LFESSQ-6, respectively. Of these,

186 B. Bannwarth et al. / Joint Bone Spine 76 (2009) 184e187

61% and 74%, respectively, were females, and their mean agewas 52.3� 17.7 (range 16e85) and 55.2� 17.1 years (range23e85), respectively.

Compared to community subjects, rheumatology outpa-tients (n¼ 178) were significantly ( p< 0.05) older(mean� SD: 53.8� 12.7 years; range 18e80) and includeda significantly ( p< 0.05) higher proportion of females(84.8%). Among rheumatology outpatients, 47% screenedpositive for LFESSQ-4 and 34.8% for LFESSQ-6. A largemajority of these were females (87% and 94%, respectively),and their age (range 22e80) averaged 54.0� 13.2 and53.7� 13.7 years, respectively.

Since 10.6% of rheumatology outpatients were confirmedFM cases according to the ACR criteria, the PPV of LFESSQ-4 and LFESSQ-6 was 22.6% and 27.4%, respectively. Thepoint prevalence of FM in the general population was there-fore estimated at 2.2% (95% CI 1.3e3.1) if the LFESSQ-4screening criterion was used, and 1.4% (95% CI 0.7e2.1) ifthe LFESSQ-6 screening criterion was used. Based on thesecriteria, the prevalence of FM was estimated at 2.6% (95% CI1.3e4.0) and 2% (95% CI 0.8e3.2), respectively, in females,and 1.8% (95% CI 0.6e3.0) and 0.7% (95% CI 0.6e0.8),respectively, in males.

Regardless of the screening criteria chosen (pain, or painplus fatigue), FM appeared to be uncommon in subjects <25years. Highest prevalence points were found in the 45e54 and75e84 age groups (Fig. 1). Based on the LFESSQ-6 screeningcriterion, the corresponding prevalence points in these agegroups were 3.9% and 4.1% in females, and 2.5% and 3.9% inmales. In addition to sex and age, a low education level wasfound to be a risk factor for FM. Conversely, the likehood ofhaving FM was not affected by any of the remaining socio-demographic variables recorded.

4. Discussion

This is the first study that aimed at providing estimates ofprevalence of FM in France. For this purpose, a telephonesurvey was carried out. Though telephone survey is subject toa coverage bias because it excludes people who do not have

0.9%

1.2%

1.6%

1.1%

0.8%

0.4%

1%

2%

3%

4%

5%

6%

[15-24] [25-34] [35-44] [4

Y

PainPain and Fatigue

Prevalen

ce [x]

Fig. 1. Prevalence of fibromyalgia syndrome in the French general population per a

and fatigue) screening criteria.

land-line phones as well as those who are not at home at thetimes of attempted contacts, it is a viable alternative to costlyface-to-face surveys in cross-sectional studies of the generalpopulation [8].

In the present study, we used the LFESSQ which wasshown to be a useful instrument in screening for FM in generalpopulation surveys of noninstitutionalized adults [5]. Thesensitivity of these criteria sets was reported to be 100% (95%CI 90.3e100) and 93.5% (95% CI 83.8e100) for theLFESSQ-4 and the LFESSQ-6, respectively [5]. Furthermore,this questionnaire was capable of distinguishing FM fromrheumatoid arthritis, with a specificity of 53.3% (95% CI35.4e71.2) and 80% (95% C 65.7e94.3) for LFESSQ-4 andLFESSQ-6, respectively, whilst no controls screened positiveusing either LFESSQ-4 or LFESSQ-6 (specificity: 100%; 95%CI 90e100) [5]. Finally, these criteria sets demonstrated highPPV, namely 56.8% (95% CI 53.0e60.6) and 70.6% (95% CI55.3e85.9) for LFESSQ-4 and LFESSQ-6, respectively, in theadult community living in London, Ontario [5]. Applyingsimilar PPV to the French general population would havegenerated prevalence estimates of FM as high as 5.6% and 3.5%, respectively. Such an approach is, however, disputablebecause it has not been established that the PPV for LFESSQin the French population is similar to those reported by Whiteet al. [5]. Ideally subjects who screened positive in our studyshould have been evaluated by a trained physician to confirmor exclude FM. Nonetheless, this methodology would haveresulted in other biases since it is likely that some peoplewould have declined to consult a rheumatologist and/or haddifficulty consulting him. Finally, we determined the PPV forLFESSQ using a rheumatology outpatients sample. Whileacknowledging that this approach is debatable, it has theadvantage of avoiding an overestimation of the actual preva-lence of FM in the general population.

Accepting the above-mentioned limitations to our data, thepoint prevalence of FM is about 1.4e2.2% in the Frenchcommunity aged over 15 years, and is primarily related to sexand age. Earlier studies undertaken in other countries providedsimilar estimates [9]. The overall prevalence of FM was esti-mated at 2% in the adult US population [4]. Using the ACR

3.9%

1.4%

3.9%

4.1%

2.8%

2.2%

2.5%

1.2%

5-54] [55-64] [65-74] [75-84]

ears

ge group. Estimates were based on the LFESSQ-4 (pain) and LFESSQ-6 (pain

187B. Bannwarth et al. / Joint Bone Spine 76 (2009) 184e187

criteria, Carmona et al. [10] and Salaffi et al. [11] reportedsimilar prevalence rates among Spanish (2.4%; 95% CI 1.5e3.2) and Italian (2.22%; 95% CI 1.36e3.19) adults, respec-tively. Conversely, the prevalence of FM was reported to be aslow as 0.75% and 0.66% (95% CI 0.28e1.29) in the Finnishand Danish populations, respectively [12,13]. These discrepantfindings may be ascribed to differences in screening instru-ments and/or diagnostic criteria used. Of note, the classifica-tion criteria [12] or tender point definition [13] used in theFinnish and Danish studies differed from those proposed bythe ACR [1]. Whether ethnic, cultural and/or environmentalvariables too may have contributed to these varying prevalencerates are unknown.

The female to male ratio of less than 3 observed in ourstudy is in line with those of earlier reports. FM was found tobe twice as prevalent in Finnish women (0.98%) compared tomales (0.48%) [12], and a female to male ratio of about 3 wasrecorded in a Canadian survey [14]. Nevertheless, this findingconflicts with what it seen in clinical practice. In fact, thefemale to male ratio was reported to be much higher in otherstudies. The prevalence of FM in the adult US population wasnearly sevenfold lower in men (0.5%) than in women (3.4%)[4]. Similarly, gender appeared to be a major determinant ofFM in the adult Spanish population since its overall prevalencewas 4.2% in females and 0.2% in males [10]. Our resultsmight partly be explained by the fact that the PPV of thescreening tool used (LFESSQ) was shown to be higher forfemales than males [5]. Furthermore, FM appeared to be age-related. There is a general agreement that FM is veryuncommon in young subjects (<25e30 years) [4,10,12,14]. Inthe adult US population, the prevalence increased with age upto 70e79 years in both sexes [4]. In other studies, the preva-lence peaked in middle aged individuals, then appeared todecline steadily [10,12,14]. In our study too, a peak prevalencewas observed at 45e54 years. We found a second peak at 75e84 years that is in better agreement with data from the USpopulation. However, it cannot be dismissed that the smallnumber of elderly individuals (�75 years) included in oursurvey (n¼ 80) resulted in an inaccurate estimate in this agegroup. Moreover, the prevalence of FM may have been over-estimated in this population since widespread musculoskeletalpain related to osteoarthritis is common in older people [15].In contrast to the marital status, low level of education wasassociated with a greater risk for FM in our survey. Of note,earlier studies found that low level of education, divorce aswell as psychological distress are significant risk factors forFM [4,12]. Moreover, it is recognized that past or currentdepression as well as anxiety is common in patients with FM[1,4]. Unfortunately, our study was not designed to addressthese issues.

5. Conclusion

Considering that a point prevalence of 1.4% would translatein approximately 680,000 patients, FM appears to be also animportant source of chronic widespread pain in France and,hence, a health and economic burden to the community.

6. Conflict of interest

This study was supported by a grant from Pierre FabreMedicaments.

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