Estimates of the Prevalence and Number of Fibromyalgia Syndrome 
Patients and Their Alpha-1 Antitrypsin Phenotypic Distribution in Ten Countries

Journal of Musculoskeletal Pain, Vol. 15, Issue 4 (2007), 9-23

Contributors and Affiliations:
Ignacio Blanco MD, Department of Internal Medicine, Hospital Valle 
del Nalón, Langreo, 33920, Spain, ignacio.blanco@sespa.princast.es
Frederick de Serres PhD, Laboratory of Molecular Toxicology, 
Environmental Toxicology Program, National Institute of Environmental 
Health Sciences, Research Triangle Park, NC, 27709-2233
Sabina Janciauskiene PhD, Department of Clinical Sciences, Malmö 
University Hospital, Malmö, Sweden
Daniel Arbesú PhD, Department of Rehabilitation Medicine, Hospital 
Valle del Nalón, Langreo, 33920, Spain
Enrique Fernández-Bustillo PhD, Biostatistics Unit, Hospital 
Universitario Central de Asturias, Oviedo, 33006, Spain
Victoriano Cárcaba PhD, Department of Internal Medicine, Hospital 
Valle del Nalón, Langreo, 33920, Spain
Izabela Nita PhD, Department of Clinical Sciences, Malmö University 
Hospital, Malmö, 20502, Sweden
Aurora Astudillo PhD, Department of Pathology, Hospital Universitario 
Central de Asturias, Oviedo, 33006, Spain


Abstract:
Objectives: During the last few years, clinical, epidemiological, and 
pathological evidence has suggested that inherited alpha-1 
antitrypsin [AAT] deficiency might play a role in the development of 
the fibromyalgia syndrome [FMS], probably because of the loss of AAT 
anti-inflammatory efficacy. The objective of this study was to 
estimate the prevalence and number of FMS patients, and their AAT 
phenotypic distribution worldwide.

Methods: A critical review selecting reliable studies on the subject.

Results: Studies on AAT gene frequencies and FMS prevalence were 
retrieved for ten countries worldwide, namely Canada, the United 
States of America [USA], Denmark, Finland, Germany, Italy, the 
Netherlands, Spain, Sweden, and Pakistan. 

The severe deficiency Z 
allele was found in all these countries, with very high frequencies 
in Denmark and Sweden [23 and 27 per 1,000, respectively], high 
frequencies in Italy and Spain [16 and 17], intermediate frequencies 
in Germany, the Netherlands, Canada, and the USA [10 to 14], and a 
low frequency in Pakistan [nine per 1,000]. 

The calculated prevalence 
of AAT deficiency and the number of FMS patients with AAT deficiency 
were 1/10 and 25,408 in Canada, 1/11 and 478,681 in the US, 1/9 and 
3,124 in Denmark, 1/ 36 and 726 in Finland, 1/16 and 48,523 in 
Germany, 1/13 and 84,876 in Italy, 1/15 and 9,639 in the Netherlands, 
1/4 and 114,359 in Spain, 1/11 and 9,065 in Sweden, and 1/25 and 
85,965 in Pakistan. Our calculations predict that AAT deficiency 
would remain undetected in around nine percent of FMS patients, with 
about eight percent of them carrying moderate deficiency phenotypes 
[MS, SS, and MZ], and less than one percent with severe deficiency 
phenotypes [SZ and ZZ].

Conclusions: Therefore, AAT phenotype characterization should be 
recommended in FMS patients and the possible efficacy of AAT 
replacement therapy in severe deficiency FMS patients should warrant 
further studies.


Keywords: Fibromyalgia syndrome, fibromyalgia syndrome prevalence, 
alpha-1 antitrypsin deficiency, epidemiological studies