The prevalence of chronic fatigue syndrome in Iceland - A national comparison by gender drawing on four different criteria

The study was carried out to estimate the prevalence of chronic fatigue syndrome (CFS) in Iceland. No previous prevalence studies known to us have been undertaken in Iceland or in Scandinavia. A 95-item custom-made questionnaire was sent to 4000 randomly selected people. The response rate was 63%. The questionnaire was constructed to include questions on all the items found in the four most common criteria for diagnosing CFS; the criteria being Australian, British and American. Results show very different prevalences according to the criteria used. The prevalence ranged from 0 to 4.9%, with the most established criteria yielding a prevalence of 1.4%. Re-test validity of the questionnaire was good, the following results are based on the selection criteria by Fukuda et al. (Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A, et al. The chronic fatigue syndrome: a comprehensive approach to its definition and study. Ann Int Med 1994;121:953-9). Women were in a majority (78%); their mean age was ...