The larger bronchi in byssinosis: a morphometric study.

The proportions of gland, muscle and cartilage were measured in the named bronchi of 43 byssinotics, and compared with the proportions in normal subjects and chronic bronchitics. The smoking habits and symptomatology of the byssinotics were also investigated. In the byssinotics the proportions of gland, muscle and cartilage were higher than in the normal, non-smoking subject at all levels in the bronchial tree, and were similar to those in chronic bronchitics. The increase was not confined to the lobar bronchi as the results of a previous investigation had suggested. It is concluded that although exposure to cotton dust is a factor in the pathogenesis of chronic byssinosis, anatomical changes in the bronchi of Lancashire cotton workers are non-specific, and are confounded by other environmental factors. Smoking has a deleterious effect on the natural history of the disease, but no morphological difference between smokers and non-smokers was found.