Hodgkin's Disease, tonsillectomy and family size

The association of tonsillectomy and Hodgkin's disease was investigated by comparison of 136 young adult patients with their 315 siblings and 78 spouses. On the basis of a case-spouse comparison, the risk ratio of Hodgkin's disease among tonsillectomized persons was 3.1 (1.5 to 7.7, 95 per cent confidence limits); on the basis of a case-sibling comparison it was 1.4 (0.8-2.6). The case-sibling analysis was repeated according to sibship size, and increased risk of disease was associated with tonsillectomy only within the 37 sibships of size two. A similar variation of risk ratio with sibship size was found in data from a prior study. The range of the association implies that the relation beteeen tonsillectomy and Hodgkin's disease either is noncausal or is complex and modified by family size. Risk of Hodgkin's disease was found to increase as a sibship size decreased, suggesting that a cause of Hodgkin's disease is correlated with childhood social class.