Chronic respiratory disease in hemp workers. A follow-up study, 1967-1974.

Many soft-hemp workers with more than 20 years' exposure to dust have chronic respiratory symptoms and obstructive lung function loss. During 7 years of follow-up, these workers had significantly higher occurrences of chronic cough and phlegm and dyspnea than control subjects and a significantly larger annual decline of forced expiratory volume in 1 second (FEV1.0) than control subjects, with a particularly marked difference between 20- to 44-year-old nonsmoking controls and hemp workers. We believe that deterioration of lung function among hemp workers begins before the age of 45 and that it continues even if further exposure to dust ceases. Textile workers should be advised to avoid further exposure to dust at a time when their ventilatory lung function (in the absence of effects of acute exposure) is sufficient to prevent future development of disabling function loss.