BACKGROUND: Numerous nosological decisions are made when moving from the common human symptom of unusual fatigue to the rare chronic fatigue syndrome (CFS). These decisions have infrequently been subjected to rigorous evaluation. METHOD: We obtained telephone interview data on fatiguing symptoms from 31406 individuals twins in the Swedish Twin Registry aged 42-64 years; 5330 subjects who endorsed fatigue and possessed no exclusionary condition formed the analytic group. We evaluated the definition and classification of CFS-like illness using graphical methods, regression models, and latent class analysis. RESULTS: Our results raise fundamental questions about the 1994 Centers for Disease Control criteria as (1) there was no empirical support for the requirement of four of eight cardinal CFS symptoms; (2) these eight symptoms were not equivalent in their capacity to predict fatigue; and (3) no combination of symptoms was markedly more heritable. Critically, latent class analysis identified a syndrome strongly resembling CFS-like illness. CONCLUSIONS: Our data are consistent with the 'existence' of CFS-like illness although the dominant nosological approach captures population-level variation poorly. We suggest that studying a more parsimonious case definition - impairing chronic fatigue not due to a known cause - would represent a way forward.
BACKGROUND: Numerous nosological decisions are made when moving from the common human symptom of unusual fatigue to the rare chronic fatigue syndrome (CFS). These decisions have infrequently been subjected to rigorous evaluation. METHOD: We obtained telephone interview data on fatiguing symptoms from 31406 individuals twins in the Swedish Twin Registry aged 42-64 years; 5330 subjects who endorsed fatigue and possessed no exclusionary condition formed the analytic group. We evaluated the definition and classification of CFS-like illness using graphical methods, regression models, and latent class analysis. RESULTS: Our results raise fundamental questions about the 1994 Centers for Disease Control criteria as (1) there was no empirical support for the requirement of four of eight cardinal CFS symptoms; (2) these eight symptoms were not equivalent in their capacity to predict fatigue; and (3) no combination of symptoms was markedly more heritable. Critically, latent class analysis identified a syndrome strongly resembling CFS-like illness. CONCLUSIONS: Our data are consistent with the 'existence' of CFS-like illness although the dominant nosological approach captures population-level variation poorly. We suggest that studying a more parsimonious case definition - impairing chronic fatigue not due to a known cause - would represent a way forward.
Authors: James N Baraniuk; Oluwatoyin Adewuyi; Samantha Jean Merck; Mushtaq Ali; Murugan K Ravindran; Christian R Timbol; Rakib Rayhan; Yin Zheng; Uyenphuong Le; Rania Esteitie; Kristina N Petrie Journal: Am J Transl Res Date: 2013-01-21 Impact factor: 4.060
Authors: Patrick F Sullivan; Tobias Allander; Fredrik Lysholm; Shan Goh; Bengt Persson; Andreas Jacks; Birgitta Evengård; Nancy L Pedersen; Björn Andersson Journal: BMC Microbiol Date: 2011-01-02 Impact factor: 3.605
Authors: Derek Pheby; Eliana Lacerda; Luis Nacul; Maria de Lourdes Drachler; Peter Campion; Amanda Howe; Fiona Poland; Monica Curran; Valerie Featherstone; Shagufta Fayyaz; Dikaios Sakellariou; José Carlos de Carvalho Leite Journal: BMC Res Notes Date: 2011-05-09