Reproductive factors in Hodgkin's disease in women: a review.

Understanding of Hodgkin's disease causes continues to be elusive. The prime etiologic candidate, Epstein-Barr virus, has been detected in only a proportion of cases, and there are few other active leads. Epidemiologic data reviewed here describe sex differences in Hodgkin's disease consistent with an involvement of reproductive and thus hormonal factors in its pathogenesis in women. This hypothesis has received very little research attention. Yet, the male predominance in incidence shows variation with age, particularly around the childbearing years, that is unusual for a malignancy. Indirect evidence relating Hodgkin's disease incidence to marital status, religion, and population parity trends demonstrates lower rates in women of presumed higher parity. Two studies that examined parity found strong but opposing associations with risk of Hodgkin's disease. The role of parity is difficult to interpret because of study design differences and the likelihood of confounding by social class. However, the incidence, clinical, and experimental findings, which should not be due to social class differences between men and women, are also compatible with a protective influence of reproductive experience in Hodgkin's disease in women. Prior infection with any ubiquitous virus seems unlikely to explain the sex differences in descriptive statistics. On the whole, the evidence suggests a role of hormonal factors in the pathogenesis of Hodgkin's disease, possibly operating through an effect on the immune system, and this hypothesis may prove fruitful to explore.