Non-malignant consequences of decreasing asbestos exposure in the Brazil chrysotile mines and mills.

AIMS: To investigate the consequences of improvement in the workplace environment over six decades (1940-96) in asbestos miners and millers from a developing country (Brazil). METHODS: A total of 3634 Brazilian workers with at least one year of exposure completed a respiratory symptoms questionnaire, chest radiography, and a spirometric evaluation. The study population was separated into three groups whose working conditions improved over time: group I (1940-66, n = 180), group II (1967-76, n = 1317), and group III (1977-96, n = 2137). RESULTS: Respiratory symptoms were significantly related to spirometric abnormalities, smoking, and latency time. Breathlessness, in particular, was also associated with age, pleural abnormality and increased cumulative exposure to asbestos fibres. The odds ratios (OR) for parenchymal and/or non-malignant pleural disease were significantly lower in groups II and III compared to group I subjects (0.29 (0.12-0.69) and 0.19 (0.08-0.45), respectively), independent of age and smoking status. Similar results were found when groups were compared at equivalent latency times (groups I v II: 30-45 years; groups II v III: 20-25 years). Ageing, dyspnoea, past and current smoking, and radiographic abnormalities were associated with ventilatory impairment. Lower spirometric values were found in groups I and II compared to group III: lung function values were also lower in higher quartiles of latency and of cumulative exposure in these subjects. CONCLUSIONS: Progressive improvement in occupational hygiene in a developing country is likely to reduce the risk of non-malignant consequences of dust inhalation in asbestos miners and millers.

Cardiorespiratory status in relation to mild deformity in adolescent idiopathic scoliosis.

We assessed the cardiorespiratory function in young persons with adolescent idiopathic scoliosis as they entered adult life; the condition had been detected and managed through a Montreal area school screening program in the years 1975 to 1979, and all patients had been discharged with stable condition. Thirty-two youths (average age 17.7 years) with Cobb angle from 3 to 32 degrees and 93 girls (average age 17.3 years) with Cobb angle from 3 to 46 degrees did not differ from their unaffected school friends in smoking habit, respiratory symptoms, lung volumes, expiratory flow rates, diffusing capacity, maximal respiratory pressures, or submaximal exercise results. When expressed as percent predicted, pulmonary functions were within the normal range in all but one patient. Normal results were also recorded in a subsample of 20 girls undergoing a more detailed progressive maximal exercise test. This information is pertinent for counseling the adolescent with scoliosis but needs to be supplemented by prospective measurements to determine the natural history of mild scoliosis in later adult life.