Terje Haug1, Per Søstrand, Sverre Langård. 1. Center for Occupational and Environmental Medicine, National Hospital, Oslo, N-0027 Norway. terje.haug@rikshospitalet.no
Abstract
BACKGROUND: Previous studies of paper machine operators have to a large extent focused on endotoxins as a possible health hazard, but not culturable micro-organisms (MOs). METHODS: Based on exposure assessment in 11 paper mills workers exposed to culturable bio-aerosols were grouped in three exposure groups. 781 exposed and 285 unexposed workers completed a questionnaire that provided data pertaining to infections and associated symptoms. RESULTS: Concentrations of culturable bacteria in process waters varied in the range 10(4)-10(6) colony forming units (cfu)/ml, and in bio-aerosols concentrations varied typically in the range 10(4)-->10(5) cfu/m3. Operators exposed to bio-aerosols reported higher cumulative incidence of symptoms associated with infections compared to the reference population (ORs = 1.7-5.9), and the group of highest exposed workers reported higher cumulative incidence than the group of lowest exposed (ORs = 1.2-3.6). CONCLUSION: Exposure to bio-aerosols containing culturable MOs may induce symptoms associated with infections among operators in paper mills.
BACKGROUND: Previous studies of paper machine operators have to a large extent focused on endotoxins as a possible health hazard, but not culturable micro-organisms (MOs). METHODS: Based on exposure assessment in 11 paper mills workers exposed to culturable bio-aerosols were grouped in three exposure groups. 781 exposed and 285 unexposed workers completed a questionnaire that provided data pertaining to infections and associated symptoms. RESULTS: Concentrations of culturable bacteria in process waters varied in the range 10(4)-10(6) colony forming units (cfu)/ml, and in bio-aerosols concentrations varied typically in the range 10(4)-->10(5) cfu/m3. Operators exposed to bio-aerosols reported higher cumulative incidence of symptoms associated with infections compared to the reference population (ORs = 1.7-5.9), and the group of highest exposed workers reported higher cumulative incidence than the group of lowest exposed (ORs = 1.2-3.6). CONCLUSION: Exposure to bio-aerosols containing culturable MOs may induce symptoms associated with infections among operators in paper mills.