Woodworkers and the inflammatory effects of softwood/hardwood dust: evidence from nasal cytology

Our primary aim was to use nasal cytology to compare a group of woodworkers with a group of unexposed subjects to see whether wood dust exposure correlates with specific patterns of inflammatory or infectious rhinitis. A secondary aim was to seek any differences in nasal symptoms or nasal cytology between workers exposed to softwood vs hardwood dust, thereby comparing the inflammatory harmful potential of the two woods. Among 117 woodworkers at factories in the Veneto region (Italy), 40 exposed to either softwood or hardwood dust were assessed by means of a questionnaire, nasal cytology, and personal wood dust sampling, and compared with 40 unexposed controls. Woodworkers reported significantly more nasal symptoms than controls (p = 0.0007). The woodworker group’s nasal smears contained significantly more neutrophils (p < 0.00001) and lymphocytes (p = 0.02) than the control group’s. The softwood workers had significantly lower levels of personal exposure to wood dust than the hardwood workers (p = 0.04); there were no significant differences in age, history of cigarette smoking, or period of exposure between these two sub-cohorts of woodworkers. A statistical trend indicated that softwood workers had more eosinophils (p = 0.05) and lymphocytes (p = 0.05) in their rhinocytograms. Nasal cytology revealed chronic inflammatory rhinitis in a significant proportion of woodworkers’ enroled in this study. It also suggested a different harmful potential for softwood and hardwood dust. Nasal cytology could prove useful in screening woodworkers for chronic inflammatory rhinitis. Further investigations are needed to examine the role of different types of wood dust in nasal inflammation.