RT Journal Article SR Electronic T1 Prevalence of chronic fatigue syndrome-like caseness in the working population: results from the Maastricht cohort study JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 464 OP 466 DO 10.1136/oem.2003.008912 VO 61 IS 5 A1 M J H Huibers A1 IJ Kant A1 G M H Swaen A1 S V Kasl YR 2004 UL http://oem.bmj.com/content/61/5/464.abstract AB Aim: To determine the prevalence of chronic fatigue syndrome (CFS)-like caseness in the working population. Methods: Using data from the prospective Maastricht Cohort Study on Fatigue at Work, the prevalence and incidence of CFS-like cases (employees meeting research criteria for CFS) were determined among 5499 employees who responded to the follow up assessment 3 years and 8 months after baseline. Results: Of the 5499 employees, 199 (3.6%) were identified as CFS-like cases. By deleting possible CFS-like cases at baseline, the annual incidence of CFS-like caseness was estimated to be 85 per 10 000. Twenty employees (0.36%) reported having been diagnosed with CFS by a physician. Conclusions: The prevalence of CFS-like cases (3.6%) was considerably higher than the prevalence of CFS reported in previous studies (0.006–3%). These findings suggest that the CFS-like caseness may be underdetected in the working population and perhaps in other populations as well.