Byssinosis in South Africa. A survey of 2411 textile workers.

The first study of the prevalence of byssinosis in the South African cotton textile industry is described. Questionnaires were administered to 2411 subjects from six textile mills. Height and weight were measured and pulmonary function was tested before and after the first shift of a working week. Dust concentrations were measured using a Lumsden-Lynch vertical elutriator sampler. The prevalence of byssinosis (all grades) according to work departments was as follows: spinning 11.2%, winding 6.1%, and weaving 6.4%. Subjects with symptoms of byssinosis had a significantly reduced forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity ratio when compared with controls matched for age, height and weight. Dust concentrations in many areas of the preparation and spinning processes exceeded the World Health Organisation's recommended permissible exposure limit for cotton dust in spinning operations. The prevalence of byssinosis in this study appears to be lower than that documented elsewhere. The mill design, machinery in use and environmental conditions in the South African cotton textile industry appear to be similar to those in Egypt and the USA before 1978. South Africa differs from these and other countries, including the UK, in having an exceptionally high labour turnover rate, which has reduced exposure periods. The subjects were found to have a high prevalence of previously treated pulmonary tuberculosis (3.4% for males and 2.2% for females), and in this population this disease appeared to cause more respiratory impairment than byssinosis.(ABSTRACT TRUNCATED AT 250 WORDS)