Chronic Fatigue

The overarching aim of this project is to shed light on a number of basic questions about chronic fatigue syndrom via a large, population-based classical twin study.

Project description

Despite considerable research, fundamental questions about chronic fatigue syndrome (CFS) remain at best partially answered. These questions include its definition, validity, the degree to which it results from genetic versus environmental factors, the nature of the substantial comorbidity observed with other conditions, and the basis of the female preponderance.

First, we collected data on ~32,000 adults aged 42-65 years (13,000 complete twin pairs) who are members of the Swedish Twin Registry for persistent fatigue, several overlapping conditions (fibromyalgia, irritable bowel syndrome, tension headache, allergy/eczema, generalized anxiety disorder, and major depression), and a detailed medical history. Second, the medical records of all twins who appeared to have CFS-like illness and a subset of those with "CFS-explained" were requested reviewed by experts.

We have addressed a set of critical questions regarding CFS. First, we estimated the prevalence of CFS and its common comorbidities (fibromyalgia, irritable bowel syndrome, tension headache, allergy/eczema, generalized anxiety disorder, and major depression) in one of the largest samples yet studied. Second, we used a variety of multivariate techniques to derive an empirical typology of prolonged fatigue and to assess how this typology compares to the CFS definition. Third, we quantified the genetic and environmental sources of variation for CFS and its comorbid conditions. Fourth, we examined the influence of gender on these sources of variation. Finally, we analyzed the patterns of comorbidity between CFS and fibromyalgia, irritable bowel syndrome, tension headache, allergy/eczema, generalized anxiety disorder, and major depression using multivariate twin analyses and thereby estimated the extent of overlap between the shared and unique genetic and environmental sources of variation.

In a follow-up study of 50 MZ twin pairs stringently discordant for CFS, we are now looking at intrapair differences in gene expression.

Financing: Supported by NIH NS41483, AI 056014

Project leader

Professor

Nancy Pedersen

Phone: +46-(0)8-524 874 18
Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8
E-mail: Nancy.Pedersen@ki.se

Collaborators

Patrick Sullivan University of North Carolina
Birgitta Evengård Labmedicin, KI
Andreas Jacks Labmedicin, KI
Karin Dahlman-Wright Novum, KI
Björn Andersson CGB, KI
Kenji Kato Japan

References

Twin research