RELATIVE CHRONIC EFFECTS OF DIFFERENT OCCUPATIONAL DUSTS ON RESPIRATORY INDEXES AND HEALTH OF WORKERS IN 3 ETHIOPIAN FACTORIES

The respiratory effects of dusts in different sections of yarn, cement , and cigarette factories were studied in 211 nonsmoking male and fema le workers aged 21-57 years. The controls used were 211 healthy nonsmo king and nonexposed male and female subjects aged 20-57 years from the general population. Forced vital capacity (FVC), forced expiratory vo lume in 1 sec (FEV1), FEV1/FVC ratio, forced expiratory pow (FEF200-1, 200 (ml)), forced mid-expiratory pow (FMF25-75%) and peak expiratory f low rate (PEFR) were recorded in all subjects with and without respira tory symptoms. Taking exposures to all dusts of different concentratio ns together it was found that the frequency of respiratory illness was greater among exposed workers (40.5% in males, 36% in females) than i t was among controls (21.6% in males, 18% in females). In exposed subj ects, the symptom prevalence was only 4.5% higher in males than in fem ales. The mean lung function indices, including FEV1, FEV1%, FEF200-1, 200 (ml), FMF25-75%, and PEFR, in subjects exposed to all dusts in gen eral decreased markedly, with dust concentration being more important than duration of exposure, and FMF being affected slightly more consis tently. About 38.4% of the dust-exposed subjects developed correspondi ng respiratory illnesses including chronic cough (24.7%), chronic bron chitis (21.8%) and bronchial asthma (24.2%). The respective control va lues were 9.0%, 9.5%, and 8.5%. Exposure to different occupational dus ts resulted in the development of respiratory illness with different r ates of prevalence. The effects of exposure to cotton and cement dusts on respiratory health of exposed subjects were relatively more signif icant (p < 0.001) than that of exposure To tobacco dust (p < 0.05). (C ) 1998 Wiley-Liss, Inc.