Pre-morbid factors in Hodgkin's disease III. School contact between patients

The question whether there is more school contact among patients with Hodgkin's disease (HD) than expected by change, suggesting that the disease might be transmissible, has been the object of several recent studies. Our study was based on the birth cohort 1930-1950 from the register of records from the school health service of the Copenhagen City Council. The cohort contains about 198 000 persons, and 65 of these had developed HD before age 40 years and in the period 1943-1975. For 62 patients, 3 matched controls for each were selected in the register, and for the remaining 3 patients at least 1 control for each was found. We analysed 36 combinations of contact measures and subsamples, and found no excess of school contact in patients relative to controls. The finding adds to the evidence against the hypothesis that HD is transmitted at school age from one future patient to another, or from a small pool of carriers.