Respiratory symptoms and ventilatory capacity were studied in 63 flour processing male bakery workers in Umtata, Transkei, Southern Africa. The controls were from a bottling plant in the same city. Both groups were black Africans from the Xhosa‐speaking population. The studied population was nonsmoking and no significant difference was noted in age, race, sex, or height between the groups. The exposed workers had significantly lower forced expiratory indices than the control group. Mean percent predicted values of forced expiratory volume in one second (FEV1), forced expiratory ratio (FEV1/FVC x 100), forced mid‐expiratory flow between 25% and 75% of FVC (FMF), forced expiratory flow between the first 200 ml and 1.200 ml of FVC (FEF 200‐1,200), and peak expiratory flow rate (PEF) were, respectively, 11.2%, 20.0%, 31.0%, 27.4%, and 36.1% lower in the exposed group compared with the controls. The prevalence of forced expiratory ratio less than 70% in the exposed group was 37% while in the controls it was 8%. The prevalence of PEF rate less than 5 l/s in the exposed group was 32% while in the controls it was 11%. The exposed workers reported a significantly higher prevalence of respiratory symptoms compared to the controls. The prevalence of nasal symptoms, phlegm, and cough in the exposed workers was 53.9%, 30.1%, and 25.4%, respectively. The present study demonstrated that exposure to flour dust in flour processing workers in the baking industry is associated with significantly lower pulmonary functions and a higher prevalence of respiratory symptoms, and that these workers show signs of airway obstruction, compared to workers not exposed to flour. Flour processing workers have a significant occupationally related respiratory impairment. Copyright © 1995 Wiley Periodicals, Inc., A Wiley Company
