Blood Groups of Miners with Coal-workers' Pneumoconiosis and Bronchitis.

An unexpected finding in a survey of a random sample of men from the Rhondda Fach valley in South Wales suggested an association between blood group A and coal-workers' pneumoconiosis. A further and larger sample of 1,250 miners and ex-miners from the same area, covering the same age range of 35 to 64 years, was chosen at random from the population in order to verify this finding. Each man was radiographed and questioned on his history and symptoms of chronic respiratory disease, and samples of blood and of saliva were obtained. The chest radiographs were classified according to the 1953 International Classification of Pneumoconiosis, and ABO and Rhesus blood groups and the secretor status were determined. No convincing association between ABO or Rhesus blood groups or secretor status and either pneumoconiosis or respiratory symptoms associated with bronchitis was found. If an association between the blood groups and pneumoconiosis in fact existed, it would manifest itself as an effect on the response to exposure to dust. Future investigations should therefore be concerned with variations in the dose-response relation rather than with variations in the prevalence of pneumoconiosis.