Exposure-response relationship between gastrointestinal problems among waste collectors and bioaerosol exposure

Objectives A high frequency of gastrointestinal problems has previously bee n reported for waste collectors. The present study relates the gastrointest inal problems to measurements of the bioaerosols that waste collectors are exposed to during work. Methods A job-exposure matrix was constructed from a combination of questio nnaire data and field measurements. The questionnaire data were collected f rom 1747 male waste collectors and a comparison group of 1111 male municipa l workers. Moreover a total of 189 full-shift personal samples was collecte d. The samples were used for characterizing the bioaerosol exposure describ ed by viable fungi, total count of fungal spores, microorganisms, and endot oxins. Results In a multivariate analysis, high exposure to endotoxins was associa ted with nausea [prevalence proportion ratio (PPR) 1.60], and the risk of r eporting nausea decreased with decreasing exposure so that workers with low exposure had the fewest reports (PPR 1.39) in the comparison with the unex posed group. High exposure to endotoxins was also associated with reports o f diarrhea (PPR 5.60), and the risk of reporting diarrhea decreased with de creasing exposure so that the workers with low exposure had the fewest repo rts (PPR 3.02). The same pattern existed for exposure to fungi, for which h igh exposure resulted in the most reports (PPR=4.59), and for diarrhea, for which low exposure resulted in the fewest reports (PPR=3.15). Conclusions An exposure-response relationship was found between nausea and endotoxin exposure and between diarrhea and exposure to both endotoxins and viable fungi.