Objective: To describe a cluster of inflammatory rheumatic diseases in an office workplace that suggests the presence of an environmental trigger.
Methods: There had been an indoor air problem in the workplace since the early 1990s. Large areas of the outer walls of the building were found to be moisture-damaged and contaminated by microbial growth. Case histories of the personnel were studied, and their working areas were related to the areas with highest microbial contamination. The incidence of inflammatory rheumatic diseases was compared with the statistics of the same geographic area.
Results: Ten patients with inflammatory rheumatic diseases (3 rheumatoid arthritis, 4 ankylosing spondylitis, 2 Sjögren's syndrome, and one of psoriatic arthritis) entitled to specially reimbursed medication were diagnosed in 1987-2000 (seven cases in 1995-1998). The incidence density ratio computed for the period 1987-2000 was 6.8 (95% confidence interval 3.6-13.0) for all office personnel and 13.2 (6.0-29.0) for those working close to the wall sustaining the worst damage.
Conclusion: The accumulation of chronic inflammatory rheumatic diseases in a single workplace suggests that some environmental exposure in this damp office had triggered the diseases.